e Various Conditions That Might Cause the MonticelloNuclear Generating Plant (MNGP) to Declare an...

7/31/2019 e Various Conditions That Might Cause the MonticelloNuclear Generating Plant (MNGP) to Declare an Emergency a

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Notice to Users

This document has been prepared for the Monticello Nuclear Generating

Plant (MNGP). Its purpose is to provide general information about

Emergency Action Levels (EALs) to off-site authorities who are involved

in planning for and responding to emergencies at the MNGP. Thisdocument is to be used for information only and is not to be used in place

of existing procedures. While this manual provides descriptions of the

various plant conditions which require emergency classification, the

Monticello Nuclear Generating Plant and the Nuclear Regulatory

Commission (NRC) remain the sole source of accurate information

regarding plant conditions during a real emergency.


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Revision 2 Monticello Nuclear Generating Plant EAL Reference Manual

i

Table of Contents

Section/Sub-Sections Tab Page(s)

How to Use This EAL Reference Manual............................................HOW TO USE ii iv

Abnormal Radiation Levels......................................................................... ....R R1 R12

Cold Shutdown / Refueling System Malfunctions ...................................... ....C C1 C27

Fission Product Barrier Degradation .......................................................... ....F F1 F12

Hazards and Other Conditions ................................................................... ....H H1 H20

System Malfunctions ................................................................................... ....S S1 S28

Independent Spent Fuel Storage Installation ............................................... ....E E1 E2

Glossary / Acronyms..........................................GLOSSARY A1 A14

Plant DataMNGP INFO B1 B5


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Revision 1 Monticello Nuclear Generating Plant NEI EAL Reference Manual

ii

How to Use This EAL Reference Manual

What the EAL Manual Does

This manual provides a clear picture of the various conditions that might cause the MonticelloNuclear Generating Plant (MNGP) to declare an emergency at the site, what these conditions are,what they mean, and what impact each is likely to have on plant and public safety. Byunderstanding what a particular condition or event means, emergency workers at the various off-siteagencies should develop a clear idea of why the matching response outlined in their own plans isappropriate. They will also be able to get a better idea of what is happening at the station during adrill or emergency.

What Is an Emergency Action Level (EAL) ?

The specific events or symptoms that would signal to station personnel that an emergency is takingplace are called Emergency Action Levels (EALs). Once a particular EAL has been reached, theEmergency Plan and related procedures specify what kinds of responses are necessary. The level ofthis response is based on how seriously the condition threatens plant and public safety, so it iscalled a graded response.

How an Emergency is Classified

There are four classifications of emergencies, each having a matching level of response.The classifications are:

Unusual Event -

A low level event which poses no threat to public safety but which warrants an increasedawareness on the part of plant and off-site agency personnel.

Alert -

Also a low level condition which poses no threat to public safety, but for whichprecautionary mobilization of certain response functions is appropriate in case conditionsdegrade.

Site Area Emergency -

At this level, conditions have degraded to a point warranting the full activation of responsefunctions. Precautionary protective actions for high risk portions of the general publicmight be recommended.

General Emergency -

Conditions have degraded to a point threatening public safety and for which some form ofprotective actions will likely be initiated.


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iii

Instructions for Using This Manual

Off-site agencies are notified at each of the four emergency levels, even though only the last one,General Emergency, actually poses a threat to public safety and warrants an action like evacuationto protect the public. Notifications are done so the agencies can prepare to respond appropriately.

Should an emergency be declared at the Monticello Nuclear Generating Plant (MNGP), within 15minutes the plant will place a phone call and send out an Emergency Notification Report Form.This notification process contains the information youll need to determine the appropriate responseactions to take. This manual provides supplemental information to help you interpret the plantconditions more easily. The notification will contain the appropriate emergency classification andother information regarding the event, including the EAL identification number.

SS1.1 is an example of an EAL identification number.

To find out more about this or any EAL, follow these directions:

1. Find the EAL number provided with the official notification that an emergency has beendeclared at MNGP. For example: EAL SS1.1

The first letter of the symbol (S) represents the type of problem and where it isdiscussed in this manual. There are six recognition categories for identifiedproblems:

R = Abnormal Radiation Levels / Radiological Effluent

C = Cold Shutdown / Refueling System Malfunctions

F = Fission Product Barrier Degradation

H = Hazards

S = System MalfunctionsE = Independent Spent Fuel Storage Installation

All System Malfunction items are discussed in the S - System Malfunctionssection of this manual. Sections of the manual are tabbed making them easy tolocate.

The second letter of the symbol (S) represents the emergency classification. Thefour emergency classification levels are:

U = Unusual Event

A = Alert

S = Site Area Emergency

G = General Emergency

Each series of EALs are listed in order of most to least severe. Example SS1, (SiteArea Emergency EALs) would be listed before SU1, (Unusual Event EALs) in theSystem Malfunctions group.


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iv

The third digit of the symbol (1) represents the sequential listing of InitiatingConditions within each recognition category. This number should not be confused asa severity level. The forth digit identifies multiple conditions or indications that mayexist for a given Initiating Condition.

2. Turn to the appropriate section of this manual which corresponds to the EAL number and

review the descriptions given. In this case, SS1, Loss of AC (Alternating Current) Power.

Note:

Some of the terms used in the detailed descriptions have special meaning. These terms have beenidentified by bold italic typeface and are defined within the glossary at the end of this manual.These terms are highlighted only the first time they appear in the detailed description.


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R- 1

SECTION R

ABNORMAL RADIATION LEVELS /

RADIOLOGICAL EFFLUENT


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R- 2

RG1 Abnormal Radiation Levels / Radiological Effluent RG1

GENERAL EMERGENCYOff-site Dose

Brief Non-Technical Description:

Radiation doses exceeding federal guidelines that specify protective measures be taken have been

measured in or projected for areas beyond the immediate station area. Protective actions will be

recommended for the public.

Detailed Description:

The thresholds specified in EALs RG1.1, RG1.2, and RG1.3 represent releases off-site that can

reasonably be expected to exceed the Environmental Protection Agency's Protective ActionGuideline values. In other words, they are the levels at which federal guidelines would recommend

protective actions like sheltering or evacuation.

The EALs call for a General Emergency to be declared if the projected dose from the release (for

the duration of the event) at or beyond the immediate station area (Site Boundary) is determined to

be greater than:

1) 1000 mRem (1 Rem) (total effective dose equivalent )

or

2) 5000 mRem (5 Rem) thyroid (committed dose equivalent)

Since these conditions could pose a threat to the public, utility personnel will recommend that the

state and local authorities consider appropriate protective actions.


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R- 3

RS1 Abnormal Radiation Levels / Radiological Effluent RS1

SITE AREA EMERGENCYOff-site Dose


Low level radiation doses have been measured at or projected for areas beyond the immediate

station area. Possible protective actions for the general public may be indicated at this level.


The thresholds specified in EALs RS1.1, RS1.2 and RS1.3 represent releases off-site expected to

exceed a fraction (10%) of the Environmental Protection Agency's Protective Action Guideline

values. In other words, they are much lower than levels at which federal guidelines recommendprotective actions like sheltering or evacuation.

The EALs call for a Site Area Emergency to be declared if the projected dose from the release (for

the duration of the event) at or beyond the immediate station area (Site Boundary), is determined to

be greater than:

1) 100 mRem (0.1 Rem) (total effective dose equivalent )

or

2) 500 mRem (0.5 Rem) thyroid (committed dose equivalent)

Possible protective actions for the general public may be indicated at this level.

If levels continue to increase, a higher level of emergency might be declared.


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R- 4

RA1 Abnormal Radiation Levels / Radiological Effluent RA1

ALERTRadiological Effluents


Radioactive gases or liquids are being released at rates at least 200 times those allowed by the

plant's operating license limits (Off-site Dose Calculation Manual) over a designated period of

time. Current plant conditions DO NOT threaten public safety.


The plant's vent system directs the gaseous output of various plant systems to the atmosphere.

Under normal plant conditions Monticello does not discharge any radioactive liquids to the river.The plant's radwaste systems remove harmful levels of radiation from any gases or liquids being

released. Gaseous and liquid releases from the plant are carefully monitored to alert operators to the

presence of, and any increase in, radioactivity.

The system monitors are set to alarm at extremely low levels of radioactivity. In fact, the alarm

points are set well below the radioactivity emission rates allowed (Technical Specifications) as

calculated from the Off-site Dose Calculation Manual (ODCM). Should there be indication of a

release, the plant operators act immediately to locate and isolate its source.

The thresholds specified in EALs RA1.1, RA1.2, and RA1.3 represent levels of radioactivity being

released at 200 times the rates allowed during normal plant operations (Off-site Dose Calculation

Manual) for more than 15 minutes. (Figure RA1). These EALs call for an Alert to be declared.

Although such release rates are significantly above that allowed for normal operations, they are still

well below that which could cause measurable radiation doses beyond the immediate area of the

plant (Site Boundary).

The conditions pose no threat to the safety of the general public.

If radiation levels continue to increase, a higher level of emergency might be declared.


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R- 6


ALERTDamage to Irradiated Fuel


Plant operators have indications of possible damage to or uncovery of reactor fuel outside the

reactor vessel. Current plant conditions DO NOT threaten public safety.


When new fuel assemblies are placed in the reactor and used to generate energy they become

irradiated. Once all of the useful energy has been taken from the fuel it is calledspent fuel. Spent

fuel is removed from the reactor vessel during plant refueling and stored in the spent fuel pool.Even though the spent fuel does not provide enough energy to produce electricity it does generate

heat for some time after being removed from the reactor.

The water in the spent fuel pool serves two functions:

1) It shields station workers from radiation given off by the fuel assemblies.

and

2) It cools the fuel assemblies by removing thedecay heat thefission products are still

producing.

The spent fuel pool is also used to store partially used fuel assemblies removed from the reactor

pressure vessel during plant maintenance.

The thresholds specified in EALs RA2.1 and RA2.2 represent conditions indicating that some

irradiated fuel outside the reactor vessel has become damaged or may be uncovered.



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R- 7

Generator

Turbine

Turbine Building

Reactor Building

Spent Fuel

Pool

Reactor Pressure

Vessel

Torus

FeedWater

Steam

Fuel

RadiationMeter

Area

Radiation Monitor

Drywell

Damage or Uncovery of

Irradiated Fuel

Figure RA2 Observations or Radiation levels indicate that irradiated fuel outside the reactorvessel may be damaged or uncovered.


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R- 8

.


ALERT

In-Plant Radiation Levels


Radiation levels in one or more area(s) of the plant are high, limiting operator's ability to safely

operate plant equipment. Current plant conditions DO NOT threaten public safety.


Control areas contain equipment necessary for the safe operation or safe shutdown of the plant.

Operators must have continuous access to these areas. Examples of control areas are:

1) Control Room (Main)

2) Central Alarm Station

3) Secondary Alarm Station

Other areas of the plant which require infrequent access, such as general Reactor Building areas,

areas of the Turbine Building, areas containing control cables, etc, are also entered to allow for safe

plant operations.

The thresholds specified in EALs RA3.1 and RA3.2 represent radiation exposure levels in one or

more control areas are higher than normal or radiation levels in areas requiring infrequent access to

maintain plant safety functions are much higher than normal. This could limit access to operating

areas that are required for safe operation or shutdown of the plant.

High radiation levels inside the plant do not mean that any radioactivity has been released off-site.



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R- 9

RU1 Abnormal Radiation Levels / Radiological Effluent RU1

UNUSUAL EVENTRadiological Effluents


Radioactive gases or liquids are being released at rates at least two times (2x) those allowed by the

plant's operating license limits (Off-site Dose Calculation Manual) over a designated period of

time. Current plant conditions DO NOT threaten public safety.


The plant's vent system directs the gaseous output of various plant systems to the atmosphere.

Under normal plant conditions Monticello does not discharge any radioactive liquids to the river.The plant's radwaste systems remove harmful levels of radiation from any gases or liquids being

released. Gaseous and liquid releases from the plant are carefully monitored to alert operators to the

presence of, and any increase in, radioactivity.

The system monitors are set to alarm at extremely low levels of radioactivity. Should there be

indication of a release, the plant operators act immediately to locate and isolate its source.

The thresholds specified in EALs RU1.1, RU1.2, and RU1.3 represent levels of radioactivity being

released at two times (2x) the rates allowed during normal plant operations (Off-site DoseCalculation Manual) for more than 60 minutes. (Figure RU1). Therefore, the EALs call for an

Unusual Event to be declared. Although such release rates are above that allowed for normal

operations, they are a small fraction of that which could cause measurable radiation beyond the

immediate station area (Site Boundary).


If radiation levels continue to rise, a higher level of emergency might be declared.


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R- 10

Radiation Meter

Generator

Turbine

Turbine Building

Reactor Building

Spent

Fuel

PoolReactor Pressure

Vessel

Primary Containment

(Torus)

Feed

Water

Steam

Fuel

Liquid Discharge Canal

Radiation Monitor

(Liquid Release)

Main Stack

Radiation Monitor

(Gaseous Release)

Radiation Meter

RadiationMeter

Reactor Building

Radiation Monitor

(Gaseous Release)

Primary Containment

(Drywell)

To river

Reactor Coolant

System

Figure RU1 Radioactive Gases or liquids are being released from the plant at rates that exceedtwo times the Off-site Dose Calculation Manual Limits for 60 minutes longer.


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R- 11

RU2 Abnormal Radiation Levels / Radiological Effluent RU2

UNUSUAL EVENTIn-Plant Radiation Levels


Increased levels of radiation have been detected inside the plant. Current plant conditions DO

NOT threaten public safety.


Radiation levels in certain areas of the plant are above normal (Figure RU2). This could indicate a

loss of control of some radioactive material within the plant. The thresholds specified in EAL

RU2.1 represent an increase in radiation levels due to an uncontrolled lowering of water levels usedfor shielding station workers from radiation given off by irradiated fuel assemblies.

The thresholds specified in EAL RU2.2 represent unplanned increases in plant radiation levels due

to a degradation in the control of radioactive materials in the plant. Therefore, these EALs call for

an Unusual Event to be declared.

Increased radiation levels inside the plant do not mean that any radioactivity has been released off-

site. The condition poses no threat to the safety of the general public.

If radiation levels continue to rise, a higher level of emergency might be declared.

.


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R- 12

Radiation Meter

Generator

Turbine

Turbine Building

Reactor Building

Spent

Fuel

Pool

Reactor Pressure

Vessel

Torus

Feed

Water

Steam

Fuel

Area

Radiation Monitor

Radiation Meter

Radiation Meter

Area

Radiation Monitors

Drywell

Typical Locations of Area

Radiation Monitors

Figure RU2 Radiation levels in some areas of the plant may restrict normal plant operations.


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C-1

SECTION C

COLD SHUTDOWN /

REFUELING SYSTEM MALFUNCTION


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C-2

CG1 Cold Shutdown / Refueling System Malfunction CG1

GENERAL EMERGENCY

Loss of Reactor Water Level


While in the cold shutdown or refueling mode, plant operators have indications that a large amount

of water has been lost from the reactor coolant system which may affect the ability to cool reactor

fuel. The ability of the plants containment system to function properly is also challenged.

Protective actions will be recommended for the public.


There are five defined plant operational conditions (modes): cold shutdown is one of them. The

term "cold shutdown" refers to a plant condition where:

1) Thereactor isshut down, that is, the nuclear chain reaction has stopped.

and

2) The reactor coolant temperature is below a temperature near the boiling point,approximately 212 F.

and

3) The Reactor Coolant System is closed, (the same condition it would be in if thetemperature was above 212 F).

Refueling is a condition where while in cold shutdown theReactor Coolant System is opened up to

allow the movement offuel assemblies in and out of the reactor or maintenance to system

components.

The thresholds specified in EAL CG1.1 represent conditions during cold shutdown or refueling

mode where the amount of water that has been lost from the reactor coolant system is affecting the

ability to properly cool the reactor core and the Containment, the third fission product barrier, is

either not intact or may fail (figure CG1). Therefore, this EAL requires that the plant declare an

General Emergency. Since the conditions could pose a threat to the public, utility personnel will

recommend that the state and local authorities consider appropriate protective actions.


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C-3

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Reactor PressureVessel

Control Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

Pool

Primary

Containment

(Drywell)

Loss of Reactor

Pressure Vessel

Water Inventory

Containment Integrity

not Maintained(or threatened)

Figure CG1 A loss of water level threatens the ability to cool the reactor fuel and the primarycontainment is not secure. (Note: Reactor vessel head and Drywell head is shownremoved in this illustration as when in Refueling Mode)


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C-4

CS1 Cold Shutdown / Refueling System Malfunction CS1

SITE AREA EMERGENCY

Loss of Reactor Water Level


While in cold shutdown, plant operators have indications that a large amount of water has been lost

from the reactor coolant system which may affect the ability to cool reactor fuel. Possible

protective actions for the general public may be indicated at this level.


There are five defined plant operational conditions (modes): cold shutdown is one of them. Theterm "cold shutdown" refers to a plant condition where:

1) The reactor is shut down, that is, the nuclear chain reaction has stopped.and

2) The reactor coolant temperature is below a temperature near the boiling point,approximately 212 F.

and

3) The Reactor Coolant System is closed, (the same condition it would be in if thetemperature was above 212 F).

The thresholds specified in EALs CS1.1 and CS1.2 represent conditions during cold shutdown

mode where the amount of water that has been lost from the reactor coolant system is affecting the

ability to properly cool the reactor core (figure CS1). The EALs include conditions in which the

operators have been unable to monitor the reactor water level for more than 30 minutes and there

has been an unexplained rise in the level of water in the drywell sump. Therefore, this EAL

requires that the plant declare a Site Area Emergency.



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C-6

CS2 Cold Shutdown / Refueling System Malfunction CS2

SITE AREA EMERGENCY

Reactor Water Level


While in the refueling mode, the operators have observed an uncontrolled loss of water level in the

reactor refueling cavity. Possible protective actions for the general public may be indicated at this

level.


When the uranium fuel pellets and surrounding metal rods (fuelassemblies) are no longer able togenerate useful heat in the core, they are removed from the reactor vesseland stored in thespent

fuel pool. When the operators prepare to remove the spent fuel assemblies, the top of the reactor

vessel (reactor vessel head) is removed and the refueling cavity is filled with water.

The water in the refueling cavity serves two functions:

1) It shields station workers from radiation given off by the fuel assemblies.

and

2) It cools the fuel assemblies by removing thedecay heat thefission products are still

producing.

Water level monitors and radiation monitors provide indications to the operators if the water level

in Reactor Vessel falls.

The thresholds specified in EALs CS2.1 and CS2.2 represent conditions during refueling mode

where the operators have observed that the water level in the refueling cavity has dropped below the

level where the fuel assemblies can properly be cooled (Figure CS2) or water level in the refueling

cavity cannot be monitored and there has been an unexplained rise in the level of water in the

containmentsump.


.


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C-8

CA1 Cold Shutdown / Refueling System Malfunction CA1

ALERT

Coolant Leakage


While in cold shutdown, plant operators have indications that a large amount of water has leaked

from the reactor coolant system or are unable to monitor the systems water level. Current plant

conditions DO NOT threaten public safety.


There are five defined plant operational conditions (modes): cold shutdown is one of them. Theterm "cold shutdown" refers to a plant condition where:


and

2) The reactor coolant temperature is below a temperature near the boiling point,

approximately 212 F.

and

3) The Reactor Coolant System is closed, (the same condition it would be in if the

temperature was above 212 F).

Normally a small amount of monitored water (coolant) is expected to leak from the components

which make up the reactor coolant system. Plant operators continually monitor the amount of this

leakage in two ways, by measuring:

1) The rate at which the tanks (drywellsumps) that collect the leakage fill up.

and

2) The rate at which water must be added to the reactor coolant system.

The thresholds specified in EALs CA1.1 and CA1.2 represent conditions during cold shutdown

mode where a large amount of water has leaked from the reactor coolant system (figure CA1) or the

operators have been unable to monitor the water level for more than 15 minutes and there has been

an unexplained rise in the level of water in the drywell sumps. Therefore, the EALs require that the

plant declare an Alert. The EALs pose no threat to the safety of the general public.


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C-9

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Reactor Pressure

Vessel

Control Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

Pool

Primary

Containment

(Drywell)

Decreasing Water

Level in the Reactor

Pressure Vessel

Sump

Figure CA1 Water level in the Reactor Refueling Cavity and Reactor Vessel is decreasingrapidly. The rate of level drop may be greater than the ability of plant systems toadd water.


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C-11

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Control Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

Pool

Primary

Containment

(Drywell)

Reactor Refueling

Cavity

Water Level below the

Vessel Flange

Sump

Reactor Pressure

Vessel Head Flange

Figure CA2 Operators have observed the water level in the Reactor Refueling Cavity isdecreasing.


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C-12


ALERT

Loss of AC Power


All AC electrical power from off-site and on-site sources has been lost for more than 15 minutes

with the plant in cold shutdown, refueling or defueled. Current plant conditions DO NOT threaten

public safety.


Much of the equipment in the plant, including important pumps and valves in safety systems, ispowered by alternating current (AC) electrical power. There are a number of main sources and

backup sources for this type of power, including:

1) Off-site AC power, which is supplied from outside the station through electric power

transmission lines, runs through transformers, then is distributed on-site by

networks calledbuses.

2) On-site AC power, which is produced by the plant or by diesel-driven electric

generators. This power supply is totally independent of the off-site electric

transmission lines.

The thresholds specified in EAL CA3.1 represent conditions during cold shutdown, refueling, or

defueled where all the off-site AC power and all the on-site AC power sources are unavailable to

run vital equipment (figure CA3) for more than 15 minutes. Because the plant is in either cold

shutdown mode, refueling mode or defueledthe operators have additional time available to restore

power before any plant damage takes place.

The EAL poses no threat to the safety of plant personnel or the general public.


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C-13

System

Transformers

DieselDriven

Generators

Unit

Transformers

AC PoweredVital

Equipment

Offsite Power

Switchyard

Vital ACPower

Bus

PowerLoss

Onsite Power

15 Min.

Figure CA3 With the plant incold shutdown, all AC Electrical Power to vital equipment has

been lost for more than 15 Minutes.


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C-14


ALERT

Decay Heat Removal


Equipment needed to maintain the reactor water temperature below the boiling point has been lost

for an extended period of time. Current plant conditions DO NOT threaten public safety.


There are five defined plant operational conditions: cold shutdown andrefueling are two of them.

The term "cold shutdown" refers to a plant condition where:

1) Thereactor isshut down; that is, the nuclear chain reaction has stopped.

and



The reactorcore is cooled by water in the Reactor Coolant System. This water is pumped through

the piping and reactor vessel. This water keeps the core completely covered and removes heat at all

times.

The thresholds specified in EALs CA4.1, CA4.2 and CA4.3 represent conditions during cold

shutdown and refueling where plant operators are unable to maintain the reactor coolant

temperature below 212 F, the Reactor Coolant System is not intact or may fail (Figure CA4), and

cooling is not restored in a timely manner. Unless the plant operators take further action, this

condition could lead to overheating of the reactor fuel and damage to the reactor core. The

conditions indicate a loss of the ability to removedecay heat and keep the core covered with water.

The EALs pose no threat to the safety of plant personnel or the general public.


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C-15

Reactor Coolant

Temperature Above(approximately) 212 F

Reactor

Pressure Value

Reactor

Fuel

Figure CA4 Operators are unable to maintain the Reactor Coolant System temperature below

212 F for a extended period.


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C-17

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Reactor Pressure

Vessel

Control Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

Pool

Primary

Containment

(Drywell)

Reactor Coolant

System Leakage

Sump

Radwaste

Collection

Tank

Figure CU1 While in Cold Shutdown a small amount of reactor coolant is leaking from theReactor Coolant System.


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C-19

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Reactor Pressure

Vessel

Control Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

Pool

Primary

Containment

(Drywell)

Unplanned Loss of

Reactor CoolantSystem Water

Sump

Figure CU2 Operators have observed an unplanned loss of Reactor Coolant System water..


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C-20

CU3 Cold Shutdown / Refueling System Malfunction CU3

UNUSUAL EVENT

Loss of AC Power


All off-site AC electrical power has been lost for more than 15 minutes. Power is still available

from on-site sources. Current plant conditions DO NOT threaten public safety.


The reactor coolant temperature is below a temperature near the boiling point,


Much of the equipment in the plant, including important pumps and valves in safety systems, is

powered by alternating current (AC) electrical power. There are a number of main sources and

backup sources for this type of power, including:






transmission lines.

The thresholds specified in EAL CU3.1 represents conditions during cold shutdown and refueling

modes where all the off-site AC power is unavailable (figure CU3) for greater than 15 minutes. The

plant is relying totally on on-site AC power to run the equipment needed to cool the plant (vital

equipment).



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C-21

System

Transformers

DieselDriven

Generators

Unit

Transformers

AC PoweredVital

Equipment

Offsite Power

Switchyard

Vital ACPower

Bus

PowerLoss

Onsite Power

15 Min.

Figure CU3 Off-site sources of AC Electrical Power have been lost for more than

15 minutes.


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C-22


UNUSUAL EVENT

Decay Heat Removal


Equipment needed to maintain the reactor water temperature below the boiling point has been lost.

Current plant conditions DO NOT threaten public safety.


There are five defined plant operational conditions:cold shutdown is one of them. The term "cold

shutdown" refers to a plant condition where:


and



The thresholds specified in EALs CU4.1 and CU4.2 represent conditions during cold shutdown and

refueling modes where plant operators are unable to maintain or bring the plant to cold shutdown(Figure CU4). Water temperatures, though still lower than normal operating temperatures, are

higher than those specified for cold shutdown. This condition indicates a loss of ability to remove

decay heat from the reactor.

The EALs pose no threat to the safety of plant personnel or the general public.


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C-23

Reactor Coolant

Temperature 212 F(approximately)

Reactor

Pressure Value

Reactor

Fuel

Figure CU4 Equipment needed to maintain the reactor coolant temperature below 212 Fhas been lost.


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C-25


UNUSUAL EVENT

Loss of DC Power


All sources of DC electrical power to a unit are degraded while the plant is in cold shut down or

refueling mode. Current plant conditions DO NOT threaten public safety.


Certain components and control devicesincluding many essential to controlling the reactor safetysystemsare powered by direct current (DC) electrical power. This DC electrical power is usually

obtained from redundant sets of reliable power supplies and batteries, then distributed to the

components and controls through conductors (buses). If the voltage from all of these redundant

supplies and batteries becomes low or is lost altogether, the safety systems themselves would be

less likely to perform as they should.

The thresholds specified in EAL CU7.1 represents conditions during cold shutdown and refueling

modes where all of the DC power supplies are degraded (figure CU7) for more than 15 minutes.

Because the plant was in cold shutdown or refueling mode before the power was lost, the operatorshave additional time available to restore power before any serious plant damage could occur.

Although vital DC power is degraded, AC (alternating current) power is still available. Therefore,

while a degraded DC power system affects the ability to control many plant components, not all

electrically operated equipment has been lost.



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C-27


UNUSUAL EVENT

Inadvertent Criticality


With the plant in the cold shut down or refueling mode, operators have indications of unanticipated

nuclear fission activity. Current plant conditions DO NOT threaten public safety.


There are five defined plant operational conditions (modes): cold shutdown and refueling are two

of them. The term "cold shutdown" refers to a plant condition where:


and



and

3) The Reactor Coolant System is closed, (the same condition it would be in if the

temperature was above 212 F).

Refueling is a condition where while in cold shutdown theReactor Coolant System is opened up to

allow the movement offuel assemblies in and out of the reactor.

When in the cold shutdown or refueling condition, plant nuclear instrumentation continually

monitors the reactor for nuclear fission activity within the reactor fuel assemblies. Normally, there

should be no significant increase in nuclear fission activity when the plant is in the cold shutdown

or refueling condition. The threshold specified in EAL CU8.1 represents a condition where plant

operators have indication there is an unanticipated increase in nuclear fission activity within the

reactor fuel assemblies.



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48/128


F-1

SECTION F

FISSION PRODUCT BARRIER

DEGRADATION


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F-2

FG1 Fission Product Barrier Degradation FG1

GENERAL EMERGENCY


Loss of 2 of 3 fission product barriers with actual or potential loss of the thirdbarrier. Protective

actions will be recommended for the public.


Fission product barriers are plant structures specifically designed to hold in (contain) and prevent

the spread of radioactive materials (fission products) created during the nuclear reaction. For the

purpose of the Emergency Plan, there are three fission product barriers, one inside the other (FigureFG1):

1) Fuel Cladding

2) Reactor Coolant System

3) Primary Containment

As long as any one of these barriers stays intact, significant amounts of radioactive fission products

cannot be released outside the station. However, if it is determined that two of the three barriers

have failed and a third is potentially or actually failing, a General Emergency will be declared.

There are certain conditions under which each of these fission product barriers could fail:

Fuel Cladding: The sealed metal tubes surrounding the fuel pellets would fail to hold in

radioactivity if the core is not cooled enough. This could happen if there is not enough water

circulating around the metal tubes to cool them, or if a loose part hits and damages the fuel

cladding.

Normally thereactor core is kept covered with water to remove heat. Even when the reactor is shut

down, the nuclear fuel produces a significant amount ofdecay heat which must be removed.

Without cooling water to remove this heat, the fuel and fuel cladding could overheat and crack.

Continued on next page


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51/128


F-4

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Reactor Pressure

Vessel and RCS

(2nd

Barrier)

Control

Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

PoolFuel

Pellet

Damaged Fuel

Cladding

Reactor Fuel

Cladding(1st

Barrier)

Primary

Containment

(3rd

Barrier)

Leak in Reactor

Coolant System

Loss of Primary

Containment

Integrity

Sump

Figure FG1 Loss of 2 of 3 Fission Product Barriers with a possibility of losing the 3rd Barrier.


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F-5

FS1 Fission Product Barrier Degradation FS1

SITE AREA EMERGENCY


Loss or potential loss of 2 of 3 fission product barriers. Possible protective actions for the general

public may be indicated at this level.




purpose of the Emergency Plan, there are three fission product barriers, one inside the other (Figure

FS1):

1) Fuel Cladding




cannot be released outside the plant. However, if it is determined that two of the three barriers have

failed or potentially failed, a Site Area Emergency will be declared.

There are certain conditions under which each of these fission product barriers could fail:

Fuel Cladding: The sealed metal tubes surrounding the fuel pellets would fail if the core is not

sufficiently cooled. This could happen if there is not enough water circulating around the metal

tubes to cool them.






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F-6

Continued from previous page:In the worst case, a loss of cooling water (a loss of coolant accident) could be combined with a

failure of the back-up systems that pump additional water to the reactor (emergency core cooling

systems). This would lead to the core becoming uncovered and inadequately cooled. Inadequate

cooling could result in the fuel cladding being damaged.

Reactor Coolant System: The Reactor Coolant System could fail to hold in radioactive materials if

radioactive water or steam leaks from it. The Reactor Coolant System forms the second fission

product barrier. To function as an effective barrier it must remain intact, withstanding the pressure

and temperature created by the water as it boils into steam. If the pressure within the reactor

pressure vesselbecomes too high, or if a mechanical failure occurs, the vessel or piping could fail,

allowing steam and water to escape into the layer of protection which lies outside it (primary

containment).

Primary Containment: The third fission product barrier, primary containment, is specifically

designed to hold in energy from the steam and radioactive materials if the first and second fission

product barriers fail. Certain extreme conditions might threaten the integrity of this layer of

containment. They are:

1) Too high a temperature in the containment

2) Too high a pressure in the containment

3) Combustible gas mixtures in containment (hydrogen and oxygen).

4) Mechanical failure of a containment isolation system.

Even if all three barriers are lostan extremely unlikely eventthesecondary containment, which

surrounds the primary containment, serves to limit the release of radioactive materials.

For EAL FS1.1, the plant operators have determined that two of the three barriers have failed.



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F-7

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Reactor Pressure

Vessel and RCS(2nd Barrier)

Control

Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

PoolFuel

Pellet

Damaged Fuel

Cladding

Reactor Fuel

Cladding(1st

Barrier)

Primary

Containment

(3rd

Barrier)

Leak in Reactor

Coolant System

Sump

Figure FS1 Loss or Potential Loss of 2 of 3 Fission Product Barriers.


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F-8

FA1 Fission Product Barrier Degradation FA1

ALERT


There are indications of a loss or potential loss to either the Fuel Cladding or Reactor Coolant

System integrity. Current plant conditions DO NOT threaten public safety.




purpose of the Emergency Plan, there are three fission product barriers, one inside the other (FigureFA1):

1) Fuel Cladding




cannot be released outside the plant. However, if it is determined that any loss or any potential loss

of either the Fuel Cladding or Reactor Coolant System has or will potentially occur, an Alert will bedeclared.

There are certain conditions under which either the Fuel Cladding or Reactor Coolant System could

fail:

Fuel Cladding: The sealed metal tubes surrounding the fuel pellets would fail if the core is not

sufficiently cooled. This could happen if there is not enough water circulating around the metal

tubes to cool them.






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F-9

Continued from previous page:In the worst case, a loss of cooling water (a loss of coolant accident) could be combined with a

failure of the back-up systems that pump additional water to the reactor (emergency core cooling

systems). This would lead to the core becoming uncovered and inadequately cooled. Inadequate

cooling could result in the fuel cladding being damaged.

Reactor Coolant System: The Reactor Coolant System could fail to hold in radioactive materials if

radioactive water or steam leaks from it. The Reactor Coolant System forms the second fission

product barrier. To function as an effective barrier it must remain intact, withstanding the pressure

and temperature created by the water as it boils into steam. If the pressure within the reactor

pressure vesselbecomes too high, or if a mechanical failure occurs, the vessel or piping could fail,

allowing steam and water to escape into the layer of protection which lies outside it (primary

containment).

For EAL FA1.1, the plant operators have determined that there is either loss or potential loss of the

fuel cladding or the Reactor Coolant System.

The EAL poses no threat to the safety of the general public.


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F-10

Primary

Containment

(Drywell)

Primary

Containment

(Torus)

Secondary

Containment

(Reactor Building)

Reactor Pressure

Vessel and RCS(2nd Barrier)

Control

Rods

Reactor Fuel

Reactor Coolant

System

Spent Fuel

PoolFuel

Pellet

Damaged Fuel

Cladding

Reactor Fuel

Cladding(1st

Barrier)

Primary

Containment

(3rd

Barrier)

Leak in Reactor

Coolant System

Sump

Figure FA1 Possible Loss of either the Fuel Cladding or Reactor Coolant System integrity.


58/128


F-11

FU1 Fission Product Barrier Degradation FU1

UNUSUAL EVENT


There are indications of a loss or possible loss of containment integrity. Current plant conditions

DO NOT threaten public safety.




purpose of the Emergency Plan, there are three fission product barriers, one inside the other (FigureFU1):

1) Fuel Cladding


3) PrimaryContainment


cannot be released outside the plant. However, if it is determined that the containment barrier is

leaking or could potentially leak, an Unusual Event will be declared.

Primary Containment is the third fission product barrier. Primary containment is specifically

designed to hold in energy from the steam and radioactive materials if the first and second fission

product barriers fail. Its effectiveness would be lessened if one of two problems occurred:

1) An opening in thedrywellortorus/suppression pool walls

or

2) A failure of the system that automatically closes the pipelines running out of

these structures (primary containment isolation system).

For EAL FU1.1, the plant operators have determined that primary containment integrity cannot be

maintained.

The EAL poses no threat to the safety of the general public.


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Revision 2 Monticello Nuclear Generating Plant EAL Reference Manual

H- 1

SECTION H

HAZARDS AND OTHER

CONDITIONS


61/128


H- 2

HG1 Hazards and Other Conditions HG1

GENERAL EMERGENCYSecurity


Station security has been compromised in a way that has caused loss of physical control of the plant

or caused the loss of the ability to maintain cooling for a freshly off-loaded reactor core in the

spent fuel pool such that imminent fuel damage is likely . Protective actions will be recommended

for the public.


Property surrounding and controlled by the station falls into two zones:

1) The Protected Area (Figure HG1) around the station includes vital plant structures

and is surrounded by a security fence. Access to this area is restricted to authorized

personnel and controlled by the Station Security Force. The Protected Area includes

both the ISFSI Protected Area and the plant Protected Area. All vital areas are

contained inside the plant Protected Area.

2) The Owner Controlled Area boundary lies outside the Protected Area boundary.

This is the property surrounding the station bounded by the outermost fence andcontrolled for security purposes.

For EAL HG1.1, a security condition exists due to hostile force intrusion which resulted in the loss

of physical control of equipmentrequired to maintain safety functions and control of that equipment

cannot be transferred to and operated from another location. Typically, these safety functions are

reactivity control (ability to shutdown the reactor and keep it shutdown), reactor water level (ability

to cool the core), and decay heat removal (ability to maintain a heat sink). The station would

inform appropriate law enforcement agencies as well as those agencies normally notified during a

General Emergency.

EAL HG1.2 addresses the failure of spent fuel pool cooling systems as result of a hostile action and

fuel damage to a freshly off-loaded reactor core in the spent fuel pool is imminent. Since these

conditions could pose a threat to the public, utility personnel will recommend that the state and

local authorities consider appropriate protective actions.


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H- 3

Figure HG1 Protected Area boundary


63/128


H- 4

HG2 Hazards and Other Conditions HG2

GENERAL EMERGENCYMiscellaneous Events


A condition exists which indicates an actual or imminent release of radioactivity as large as that

associated with a General Emergency. Protective actions will be recommended for the public.


EAL HG2.1 provides the Emergency Director the latitude to declare a General Emergency based

on his or her own experience and judgment. It applies to any condition (not already described by

another specific EAL) which involves the actual or potential release of radioactivity in amountsrequiring protective actions for the public. Releases can be reasonably expected to exceed EPA

Protective Action Guideline exposure levels off-site for more than the immediate site area.




64/128


H- 5

HS2 Hazards and Other Conditions HS2

SITE AREA EMERGENCYControl Room Evacuation


The Control Room has been evacuated and plant operators have been unable to establish control of

plant systems from remote locations within 10 minutes. Possible protective actions for the general

public may be indicated at this level.


Normally the plant is operated, monitored, and controlled from the Control Room. If fire, smoke,

radiological hazards, or something else were to force plant operators from the Control Room, they

would still be able to take control of the plant from other locations (remote shutdown panels).

From these panels they can perform critical functions normally performed from the Control Room.

The thresholds specified in EAL HS2.1 represent conditions in which the operators have evacuated

the Control Room but have been unable to gain control of critical plant functions from the remote

shutdown panel(s) within a reasonable amount of time (10 minutes). If control cannot be

established, the ability to maintain thereactor in a safe and stable condition is degraded.



65/128


H- 6


SITE AREA EMERGENCYAdditional Items


Conditions in the plant exists which call for the kind of response associated with a Site Area

Emergency. Possible protective actions for the general public may be indicated at this level.


EAL HS3.1 provides the Emergency Director the latitude to declare a Site Area Emergency based

on his or her own experience and judgment. It applies to any condition (not already described by

another specific EAL) which involve the actual or potential failures of plant safety systems neededto maintain the reactor in a safe condition and protect the public.



66/128


H- 7


SITE AREA EMERGENCYSecurity


The site has come under a dedicated attack by hostile force within the plant Protected Area. This

condition, by itself, poses no immediate threat to public safety.




1) The Protected Area (Figure HS4) around the station includes vital plant structures

and is surrounded by a security fence. Access to this area is restricted to authorized


both the ISFSI Protected Area and the Plant Protected Area.


This is the property surrounding the station bounded by the outermost fence and

controlled for security purposes.

The thresholds specified in EAL HS4.1 represent acts within the plant Protected Area toward the

site or its personnel that includes the use of violent force to destroy equipment, take hostages,

and/or intimidate the licensee to achieve an end. This includes attack by air, land, or water using

guns, explosives, projectiles, vehicles, or other devices used to deliver destructive force. It does not

include acts of civil disobedience or felonious acts that are not part of a concerted attack on the site.

Other EALs address these events.

The EAL is not premised solely on the potential for a radiological release. Rather the issue includes

the need for assistance due to the possibility for significant and indeterminate damage from

additional attack elements.


67/128


H- 8

Figure HS4 Protected Area boundary


68/128


69/128


H- 10

HA2 Hazards and Other Conditions HA2

ALERTFire or Explosion


A fire or explosion, which will likely affect the operation of a plant safety system, has occurred.

Current plant conditions DO NOT threaten public safety.


Any plant system which performs a function critical to plant safety is referred to as asafety system.

Most safety systems have many backups to ensure required operations can be performed.

EAL HA2.1 covers a fire or explosion in the plant large enough to cause damage to one or more of

the plant safety systems.

The condition poses no threat to the safety of the general public.


70/128


H- 11


ALERTToxic or Flammable Gas


A toxic, asphyxiant, or flammable gas has been released into a vital area of the plant. Current

plant conditions DO NOT threaten public safety.


Vital Areas are so named because they contain vital security or safety systems. Releasing

potentially harmful quantities of toxic, asphyxiant, or flammable gases in or near a vital area could

affect the safe operation of the plant or threaten the health of station workers.

The thresholds for EALs HA3.1 and HA3.2 represent toxic/asphyxiant/flammable gas

concentrations that prevent or severely limit access to Vital Areas of the plant.

This condition poses no threat to the safety of the general public.


71/128


H- 12


ALERTSecurity


The site has come under a dedicated attack by hostile force within the Owner Controlled Area.

This condition, by itself, poses no immediate threat to public safety.

OR

The site has been informed by the NRC of a credible threat of an airliner attack less than 30

minutes away. Current plant conditions DO NOT threaten public safety.


Property surrounding and controlled by the station falls into two zones (Figure HA4):

1) The Protected Area around the station includes vital plant structures and is

surrounded by a security fence. Access to this area is restricted to authorized


both the ISFSI Protected Area and the Plant Protected Area.


This is the property surrounding the station bounded by the outermost fence and

controlled for security purposes.

The threshold specified in EAL HA4.1 represent acts within the Owner Controlled Area outside the

Plant Protected Area toward the site or its personnel that includes the use of violent force to destroy

equipment, take hostages, and/or intimidate the licensee to achieve an end. This includes attack by

air, land, or water using guns, explosives, projectiles, vehicles, or other devices used to deliver

destructive force. It does not include acts of civil disobedience or physical disputes between

employees within the OCA. Other EALs address these events.

EAL HA4.2 is intended to address the contingency of a very rapid progression of events due to an

airborne terrorist attack such as that experienced on September 11, 2001. This EAL is not premised

solely on the potential for a radiological release. Rather the issue includes the need for assistance

due to the possibility for significant and indeterminate damage from such an attack.

These conditions pose no threat to the safety of the general public.


72/128


H- 13

Red = Protected Area FenceLight Blue = Owner Controlled Area Fence

Figure HA4 Security Zones at Monticello Nuclear Generating Plant


73/128


H- 14


ALERTControl Room Evacuation

Brief Non-Technical Description:The Control Room is being evacuated. Control of plant systems is being established from another

location within the plant. Current plant conditions DO NOT threaten public safety.


Normally the plant is operated, monitored, and controlled from the Control Room. If fire, smoke,

radiological hazards, or something else were to force plant operators from the Control Room, they

would still be able to take control of the plant from other locations (remote shutdown panels).

From these panels they can perform all critical functions normally performed from the Control

Room.

For EAL HA5.1, the operators have started an evacuation of the Control Room. If the operators can

not establish control of critical safety functions, within a reasonable amount of time after evacuating

the Control Room, a higher level of emergency would likely be declared.



74/128


H- 15


ALERTMiscellaneous Events


Conditions exists in the plant which call for the kind of response associated with the Alert

classification. Current plant conditions DO NOT threaten public safety.


EAL HA6.1 provides the Emergency Director the latitude to declare an Alert based on his or her

own experience and judgment. It applies to any condition (not already described by another

specific EAL) which involves an actual or potential substantial decrease in the level of safety of theplant.



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H- 16

HU1 Hazards and Other Conditions HU1

UNUSUAL EVENTNatural or Man-made Events


A destructive event has occurred within the plant protected area of the station. Current plant

conditions DO NOT threaten public safety.


The plant and its equipment are designed to withstand most natural events (earthquakes, floods,

high winds, tornados, etc.) or any damage which may occur from various man-made destructive

incidents (such as a vehicle striking plant structures).

EALs HU1.1, HU1.2, HU1.3, HU1.4, HU1.5, HU1.6, and HU1.7 address one of the following

events that has occurred:

An earthquake has been felt on-site by plant personnel (HU1.1)

A tornado or wind greater than 100 mph striking within the plantProtected Area

(HU1.2)

Vehicle collision affecting plant structures or systems within the plantProtected

Area. (HU1.3)

Unanticipated explosion within theplant Protected Area (HU1.4)

Damage to the main turbine, in which parts of the turbine have penetrated the

turbine casing. (HU1.5)

Uncontrolled flooding in areas of the plant which may affect safety related

equipment. (HU1.6)

Hi or low river level which may effect the performance of plant systems (HU1.7)

These EALs require that an Unusual Event be declared.



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H- 17


UNUSUAL EVENTFire


A fire lasting more than 15 minutes has occurred within the plant. Current plant conditions DO

NOT threaten public safety.


Within the plant, or areas contiguous to the plant, any significant fire (that is, one lasting more than

15 minutes from the time of detection) potentially threatens plant safety. Those large enough to

require fire brigade activation might both endanger personnel and cause significant propertydamage. In addition, the Fire Brigade Leader shall evaluate the need for off-site fire fighting

assistance.

EAL HU2.1 applies to buildings and areas contiguous (in actual contact with or immediately

adjacent) to plant Vital Areas or other significant buildings or areas.

Depending on how severe the fire or explosion is, a higher level of emergency might be declared.


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78/128


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H- 20


UNUSUAL EVENTMiscellaneous Events


Conditions in the plant exists which call for the heightened awareness and notifications associated

with the Unusual Event classification. Current plant conditions DO NOT threaten public safety.


The EAL HU5.1 provides the Emergency Director the latitude to declare an Unusual Event based

on his or her own experience and judgment. It applies to any condition (not already described byanother specific EAL) which potentially threatens the safety of the plant.



80/128


S- 1

SECTION S

SYSTEM MALFUNCTIONS


81/128


S- 2

SG1 System Malfunctions SG1

GENERAL EMERGENCYLoss of AC Power


All AC electrical power from off-site and on-site electrical power sources has been lost and it is not

expected to be restored for a prolonged period of time. Protective actions will be recommended for

the public.


Much of the equipment in the plant, including important pumps and valves in safety systems, is

powered by alternating current (AC) electrical power. There are a number of main sources andbackup sources for this type of power, including:






transmission lines.

The thresholds for EAL SG1.1 represents a condition where all AC power sources have been lost

(Figure SG1). If all AC power is lost for a prolonged period of time (4 hours), the ability to cool

the reactorcore could be lost.




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S- 3

System

Transformers

DieselDriven

Generators

Unit

Transformers

AC PoweredVital

Equipment

Offsite Power

Switchyard

Vital ACPower

Bus

PowerLoss

Onsite Power

4 Hr.

Figure SG1 All AC electrical power is expected to be lost for more than 4 hours.


83/128


S- 4

SG2 System Malfunctions SG2

GENERAL EMERGENCYReactor Power


The reactor control rods failed to shut down the reactor and adequate core cooling cannot be

maintained. Protective actions will be recommended for the public.


A reactor SCRAM is a way to rapidly shut down the reactor (bring it sub-critical) by quickly

inserting all thecontrol rodsinto the reactorcore. Reactor SCRAMs can be initiated either directly

by the operators (manually) or by theReactor Protection System(automatically).

If, however, a reactor SCRAM is started and the control rods do not insert, the reactor may not shut

down fully. Emergency Operating Procedures provide direction to the operators on alternate ways

to shut down the reactor. If the reactor does not fully shut down and alternate ways to shut it down

fail, the reactor may continue to produce heat. In this case, automatic and manual signals to shut

down the reactor have failed and the reactor is still generating power and the ability to maintain

adequate core cooling cannot be assured (Figure SG2). Unless plant operators take further action

to shutdown the reactor and establish core cooling, this condition will threaten one or more of the

structures designed to hold in the plants radioactive material (fission product barriers).

The threshold of EAL SG2.1 represents conditions where the failure to complete a SCRAM (both

automatically and manually) has occurred and there is indication of an extreme challenge to the

ability to cool the core.

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