KANUPP Response to Fukushima

Zakir Noor KhanDeputy Chief Engineer, K-2/K-3 Project

Background

� In response to Fukushima NPPs Accident, PAEC Corporate Office called a meeting on 25 March 2011 to discuss the safety of KANUPP and CHASHMA NPPs

� Targeted Action Plan issued for KANUPP by Corporate Office on 22 June 2011

� PAEC Corporate Office so far conducted 05 reviews of FRAP

� Quarterly progress report is being sent to Corporate Office

� 6th Progress Review of FRAP due in Jan 2015

2/23

2

Areas of Safety Concern

1. External Natural Hazards

2. Make-shift AC Power

3. DC Power Capacity

4. Fire Protection and Control

5. Emergency Cooling

6. Hydrogen Hazard

7. Containment Integrity

8. Spent Fuel Cooling

9. EOPs, SAMGs (On-Site Actions)

10. Emergency Preparedness (Off-site Actions)

3

Status of FRAP Tasks

3/23

DescriptionMain Tasks Studies Actions

# % # % # %

Total 84 - 79 - 443 -

Completed 68 81 74 94 246 56

In progress 16 19 05 06 197 44

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Post-Fukushima Strategy For Modifications

� Enhancement in defense-in-depth

� Use of simple technology

� Easy to implement

� No change in existing logic(s)

� Indigenous efforts (analyses, engg. & implementation)

� Insignificant increase in risk

� Cost effective

1. External Natural Hazard - Earthquake

5

� Original design of KANUPP was based on PGA of 0.1g

� For seismic qualification of older NPPs, the global approach is to re-

assess seismic capacity of plant's structures and equipment through

seismic walk-down

� In 1993, IAEA Seismic Walk Down Mission was invited for re-

assessment of seismic capacity of the plant

� IAEA mission concluded that the plant can withstand seismic event

of twice the original design value of 0.1g with minor seismic

retrofits (easy fixes)

� Sesimic retrofits installed in Re-licensing Outages (RLOs) in 2003 &

2006

Seismic Retrofits / Anchoring (≥ 0.2g)

8/23Anchoring of DGs Local PanelReinforcement of Cable Trays

Strengthening of Wall near DG3 bus in Dist. RoomStrengthening of Wall above DG3 bus bar

1. External Natural Hazard – Tsunami/Flooding

7

� In 1945, the great earthquake of magnitude 8.3 caused 10 m height tsunami at Pasni (~275 miles from KANUPP) and only 1.5 m wave height at Karachi.

� In 2004, a study was carried out (based on field evidences) for assessment of tsunami hazard for KANUPP concluded that maximum height of the wave resulting from the tsunami would be up to 3.28 ft (~ 01 m).

� The heaviest rain fall recorded so far during last 50 years in a day ~ 10 inches. The max. rain fall caused flooding in city but plant remained unaffected.

� KANUPP is 39´(~ 12 m) above sea level, quite safe from tsunami.

� Distribution room, EDGs, fuel tanks, FIJW DGs and EFW located at ground level (39 ft above sea level).

Flooding Protection (≥ 3 ft)

9/23

WallSliding Gate Flap Gate

2. Make-Shift AC Power

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� Main output transformer supplies power at 132 kV to the utility system transmission lines through the station switchyard bus.

� In case of loss of off-site power, essential loads of plant are supplied by two 100% duty Emergency Diesel Generators (EDGs).

� A third EDG of same capacity is available as SBO Diesel Generator.

� On-site diesel fuel storage capacity of 05 days is available for operation of one EDG.

� In case of SBO, Emergency Feedwater System (dedicated DG) will remove decay heat

Enhancement of Emergency Power Sources

10

� Provision to energize plant essential buses through existing emergency core cooling DGs (Completed)

� Integration scheme for energization of plant essential buses through 300 kWe mobile / fixed DG (Completed)

� 01 new DG set is under procurement

Connecting Breaker Panel for

Essential Bus

Interconnection scheme of 300 KWe DG

Make-Shift AC Power (Backup Power to Essential Buses)

12/23

FIJW- DGs Connecting Breaker Panel for Essential Bus

300 KWe DG (under procurement) Interconnection scheme of 300 KWe DG

Elevated at 37 ft from ground ( 76 ft from MSL)

Enhancement of Emergency Power Sources

10/23

To charge battery bank, PLC for monitoring & signally, operating ECC Valves & emergency lighting

Bowser for fuel transfer

Using extra capacity of FIJW-DGs to operate limited essential loads

To provide power to essential buses (as a last resort)

3. DC Power Capacity

13

� 02 battery banks DE-BY1 & BY2 (230V DC) provide power to station emergency lighting, inventors and DC motors ~ 01 hr in case of SBO

� 04 more battery banks BY3-BY6 (220V AC and 24V DC UPS) added as a result of technological advancement e.g. instrumentation control and process computer during Re-licensing (2003)

� Backup time of 220V AC and 24V DC UPS ~ 10 hrs

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Improvement Actions to Enhance DC Power

� Preparation of DC conservation procedure to improve battery back time of 230V DC from 01 to 07 hrs.

� Installation of a 100 kVA DG set and its integration scheme (at higher elevation, resilience from earthquake and tsunami)

� To provide continuous power supply (through 24V DC UPS and 220V AC UPS systems) to control, monitoring and signaling systems in case of unavailability of essential power for longer duration.

� To provide alternate power to ECC MOVs.

� To shift existing 230V DC emergency lighting (currently integrated in distribution room at ground level) to 220V AC UPS to enhance its reliability.

DC Power Capacity Enhancement Measures

11/23

100 KVA DG (37’ above ground) Transformers Main Distribution Panel

220V AC Changeover 24V DC Changeover ECC MOVs Changeover Switch Panels

Fire Prevention and Control

13/23

Refurbishment of Existing Fire Tender

New Fire Tender (under procurement)

New Fire Alarm System (under Study Phase)

Emergency Core Cooling – Design Features

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� Passive cooling of core through rundown of Primary pumps, thermosyphoning

� In case of SBO, independent sesimically qualified Emergnecy Feedwater (EFW) system acts as an alternate heat sink.

� Emergency Core Cooling Systems i) Medium Pressure Forced Emergency Injection Water (FIJW) System ii) Low Pressure Emergency Injection Water (IJW) system. IJW provides continuous long term core cooling.

� Auto Boiler Crash cooling system provides quick reduction in primary heat transport system pressure to facilitate injection of FIJW/IJW.

� Reactor vault contains large quantity of light water which can remove the heat from the core debris and retain it within calandria for a long period of time.

Additional Measures For Core Cooling (Direct / Indirect)

BFW-TK1

(27740 IG)PW-TK1

(2000 IG)

Spent Fuel Bay

Boilers

Vault Cooling

Core Cooling

FW Ring

Flexible Hose

Diesel Driven Pumps (02)100 igpm, 100 psiDousing Spray

Gravity Feed Line

DMW-TK1

(20000 IG)

SEA

WATER

RFW-TK2

(20000 IG)

~06 days

~01 day

~05+05 days

14/23

Emergency Core Cooling Provision(Indefinite Time)

15/23

Diesel Driven Pump Interconnection with Water Tank

Suction and Discharge Header Piping Layout

Hydrogen Hazard

16/23

Passive Autocatalytic Recombiners (12 PARs) H2 Monitoring Equipment

Containment Integrity under Severe Condition

Pe

ne

tra

tio

n

CO

NTAIN

MEN

T

STA

CK

Ven

t Tan

k

Water Storage TankFeed through pump or gravity

Diesel Driven

Recirculation Pump Drain Valve

(Aliq

uate

336)

(Alk

alin

e s

olu

tion

(Thio

sulp

hate

)

Concrete Shielding

Rupture Disk

To Stack

To Dryer

Active

Passive

Orifice

MD8MD7

MD10MD9

6”

3”

3”

17/23

Containment Filtered Venting System

Enhancement for Emergency Preparedness

Gamma Spectrometry System Satellite PhoneKI Tablets

Environmental Monitoring LabElectronic Pocket DosimeterManpower Enhancement19/23

Service Building

FIJW-TK1, 180 ton H2O for 100 min or 1.66 hrs

EL = 120’

P

Sump

EL = 110’

Reactor Building

MH-TK1

EFW-TK1

EFO-TK1

3175 USG

EFO-TK2, 750 USG

FIJW-DG1/DG2

EFO-TK3240 USG

EFO-TK4240 USG

N-BoilersS-Boilers

2 x EFW-PPs

400 KW each

150 KW each

For one FIJW-DG

for 96 hours

With RFW-TK2 for 36 hrs

Spent Fuel Bay

Ground Level =

138 ft elevation

(1):- Re-assessment of Tsunami / flooding / earthquake (seismic supports)…

Maximum Tsunami Wave = 109.31 ft

139 ft elevation

Distribution Room 100% Sealing

220V AC , 24 V DC Batteries

(1):-

Pro

pe

r an

d e

ffectiv

e D

rain

ag

e S

yste

m

(1):- Early Tsunami Warning System (TEWS) from PMD

(2):- FIJW-DGs connection to essential busses

(3):- Alternate power to

essential ECCS valves

(2):- Mobile DG - 300 KW(3):- Station Emergency Lighting from 220V UPS

(4):- Strengthening in fire fighting capabilities

(6):-PARs and H2 Analyzer

(7):-Containment

Max press = 40 psig.

Filters

Venting

System

Overall Concept of KANUPP Fukushima Response Action Plan (FRAP-K1)

(8):- Spent Fuel Cooling

Arabian Sea

FIJW System

IJW System

MH System

(6):- Max H2 =

7% by Vol.

Essential Bus Essential Bus

(3):- 100 kVA DG for continuous charging of batteries

(5) BYW

(5) FIJW

(5) EFW

(5) VCW

(5) DSW

PHT

System

~

1. External Natural Hazards

2. Make-shift AC Power3. DC Power Capacity4. Fire Protection and Control

5. Emergency Cooling6. Hydrogen Hazard7. Containment Integrity8. Spent Fuel Cooling9. EOPs, SAMGs (on-site)10. Emergency Preparedness

Mean Sea level = 100 ft elevation

Building Spray

Fire tender

Pump House = 109 ft elevation

2

3

7

4

2

EFW-DG1/DG2

(1):- Water tight sluice gates

Core

DMW-TK120000 IG

PW-TK12000 IG

BFWTK1277400 IG

RFW-TK120000 IG Water

Injection

176 ft elevation

23/23