TP-1 HPT001.016 Rev. 4 Page 1 of 66 TVAN Technical Training Health Physics (RADCON) Initial Training...

TVAN Technical TrainingHealth Physics (RADCON) Initial Training Program

TP-1

HPT001.016Rev. 4

Page 1 of 66

ALARAAs Low As is Reasonably

Achievable

http://www.tva.gov/


TP-2

HPT001.016Rev. 4

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Enabling Objectives - 1

• Define ALARA & Describe Concepts

• Explain Stochastic & Nonstochastic Effects & Describe Differences

• State Aim of ALARA & How Achieved

• Identify Regulatory Basis for ALARA

• Define “Acceptable” and “Total” Risk

• Responsibilities for Implementing ALARA

http://www.tva.gov/


TP-3

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• Identify the ALARA Committee and Functions

• State the ALARA Goal Setting Process

• State Criteria for ALARA Planning Report & Post-Job Report

• Identify Responsibilities for the Annual ALARA Report

• Identify Six Items in the Pre-Job Brief

http://www.tva.gov/


TP-4

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• State Means to Reduce Cobalt

• Identify the Desired Type of Control

• List Four Exposure Reduction Techniques

• Identify Regulatory Basis for Change Evaluations

• State two Consequences of Removing Shielding Without Approvals

http://www.tva.gov/


TP-5

HPT001.016Rev. 4

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Radiation Protection

Radiation Protection is concerned with the protection of Individuals, their Progeny and Mankind as a

whole, while still allowing necessary activities from which radiation

exposure might result.

http://www.tva.gov/


TP-6

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Purpose of ALARA

Minimize Risk as a Result of Exposure to Radiation or Radioactive Material to Employees and the Public to a Level that is As Low As is Reasonably Achievable (ALARA)

http://www.tva.gov/


TP-7

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ALARA

• Make Every Reasonable Effort

• Maintain Radiation Exposures as far Below the Dose Limits as is Practical

• Consistent with Purpose of Licensed Activity

• Consider State of Technology and Economics vs. Benefits Provided

http://www.tva.gov/


TP-8

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ALARA Goal

• Maintain ALL Exposures ALARA

- Individual Exposures – Rem- Collective Exposures – Sum of Doses received by all exposed Individuals – Man-rem

Don’t reduce individual exposure at the expense of population exposure.

http://www.tva.gov/


TP-9

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Acute & Chronic Doses

Acute Radiation Dose – A relatively large dose of Radiation received in a short period of time.

Chronic Radiation Dose – The sum of small radiation doses received repeatedly over long periods of time.

http://www.tva.gov/


TP-10

HPT001.016Rev. 4

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Nonstochastic Health Effects

• Health Effects, the severity of which varies with the dose and for which a threshold is believed to exist.

Example - Radiation-Induced cataract formation

http://www.tva.gov/


TP-11

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Stochastic Health Effects

• Health Effects that occur randomly and for which the probability of the effect occurring, rather than its severity, is assumed to be a linear function of dose without threshold.

Examples – Hereditary effects and cancer incidence.

http://www.tva.gov/


TP-12

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Aim of Radiation Protection

• Prevent detrimental nonstochastic effects and limit the probability of stochastic effects to levels deemed acceptable.

http://www.tva.gov/


TP-13

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To Achieve Aim: (1)

• Nonstochastic Effects – Set dose limits at sufficiently low values so that no threshold dose would be reached.

http://www.tva.gov/


TP-14

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To Achieve Aim: (2)

• Stochastic Effects – Keep all justifiable exposures as low as is reasonably achievable, taking into account economic and social factors and ensuring that appropriate dose equivalent limits are not exceeded.

http://www.tva.gov/


TP-15

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Basis for ALARA

• Regulation: 10CFR20.1101“The licensee shall use, to the extent practical, procedures and engineering controls based upon sound radiation protection principles to achieve occupational doses and doses to members of the general public that are as low as is reasonably achievable (ALARA).”

http://www.tva.gov/


TP-16

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Guidelines for ALARA

• Regulatory Guides:- RG 8.8, Maintaining exposures at nuclear power stations ALARA.

• - RG 8.10, Guidance for maintainingoccupational exposures ALARA.

- RG 8.29, Risks from occupationalradiation exposures.

http://www.tva.gov/


TP-17

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Acceptable or Comparable Risk

• The occupational dose limit for adult workers (5 rem/y), combined with the application of ALARA principles, provides a level of risk of delayed effects considered acceptable by the NRC (stochastic effects), or comparable to risks associated with other “safe” industries. (RG 8.29)

http://www.tva.gov/


TP-18

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Total Risk Concept

• In evaluating specific activities, the concept of “total” risk reduction should be considered. (RG 8.29)

- Consider the sum of external andinternal exposures.

http://www.tva.gov/


TP-19

HPT001.016Rev. 4

Page 19 of 66Total Risk Concept:Example

• The use of respirators can lead to increased work time in radiation areas, which increases external doses.

• The advantage of using respirators to reduce internal exposure must be evaluated against the increased external exposure.

http://www.tva.gov/


TP-20

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Components of ALARA

• Training

• Planning

• Cost-Benefit Analysis

• Implementation

• ALARA Suggestion Program

http://www.tva.gov/


TP-21

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Cost-Benefit Analysis

• Costs:

- Equipment Dollars- Labor Dollars- Risk in Dollars of exposure received

• Benefits:- Dollars saved by use of ALARA- Exposure saved, Dollars

Assign a value of $25,000 for each rem.

http://www.tva.gov/


TP-22

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Cost-Benefit Example

• Proposal to add shielding to piping• Cost:

- (equipment & labor) = $359,000- 8 man-rem X $25,000 = $200,000- Total cost = $559,000

• Benefit:- Reduced dose: 0.95 man-rem/month

for 2 year fuel cycle = 22.8 man-rem.- Total benefit = $570,000

http://www.tva.gov/


TP-23

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ALARA Responsibilities - 1• Corporate Manager, Radiological and

Chemistry Services- Recommend and Document ALARA

Policy• Radchem Manager

- Administer site ALARA Program• Each Individual

- Seek methods to save or reduceman-rem exposure.

http://www.tva.gov/


TP-24

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ALARA Responsibilities - 2• RADCON staffs:

- Maintain ALARA dose tracking.- Review radiation exposures.- Prepare Annual ALARA Report.- Pursue reduction of occupational

radiation exposures.- Promote ALARA attitude- Implement RADCON requirements

http://www.tva.gov/


TP-25

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ALARA Responsibilities - 3

• Each Individual should:- Seek methods to save or reduce

man-rem exposure.- Comply with procedures & practices.- Report hazardous/changing condition- Minimize personal radiation exposure- Track individual dose status.- Avoid exceeding dose limits.

http://www.tva.gov/


TP-26

HPT001.016Rev. 4

Page 26 of 66ALARA CommitteeResponsibilities

• Review effectiveness of ALARA program.

• Track ALARA goals.

• Review ALARA suggestions.

• Review ALARA planning documents for jobs exceeding 5 man-rem TEDE.

• Review exposure trends.

http://www.tva.gov/


TP-27

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ALARA Committee

• Chaired by Site VP, Plant Manager or designee

• Members from:- RADCON - Modifications- Operations - Engineering- Outage - Maintenance- Nuclear Assurance- Training

http://www.tva.gov/


TP-28

HPT001.016Rev. 4

Page 28 of 66ALARA GoalsObjectives

• Objective – Minimize TEDE.

• Ensures continued awareness in radiological control.

• Established by functional areas and approved by Site VPs.

http://www.tva.gov/


TP-29

HPT001.016Rev. 4

Page 29 of 66ALARA GoalsPurposes

• Set organizational exposure goals.• Set annual station man-rem goals.• Goals for major outages or work events• Goals for routinely performed

operations.• Emphasize administrative dose levels.• Incentives for improving performance.• Focus attention at all levels of ALARA.

http://www.tva.gov/


TP-30

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Setting ALARA Goals

• Identify the task, components, sources.

• Identify number of workers & time .

• Review radiation survey results.

• Review past history.

• Develop exposure estimate.

• Identify exposure reduction potential.

• Establish dose/dose rate action levels.

http://www.tva.gov/


TP-31

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ALARA Planning Report

• Form SPP-5.2.1, “Preliminary Radiological Impact/Evaluation Checklist.”

• Issued when plant specific criteria met, for example when TEDE for a specific task expected to exceed 1 man-rem.

http://www.tva.gov/


TP-32

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Post-Job Report

• Required if:

- Pre-Job Report was required,

- Dose exceeds estimated dose by25 percent or greater,

- TEDE exceeded 1 man-rem.

http://www.tva.gov/


TP-33

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Annual ALARA Report

• Submitted by RADCON to Site VP• Includes:

- Comparison of ALARA Results withALARA Goals.

- Comparison of ALARA Results withResults in previous years.

- ALARA Goals for coming year.

http://www.tva.gov/


TP-34

HPT001.016Rev. 4

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Pre-Job Briefing

• Conducted when TEDE expected to exceed 1 man-rem.

• Incorporates appropriate ALARA considerations.

• Attended by all personnel directly involved in the work.

• Scheduled as near as possible to start of job.

http://www.tva.gov/


TP-35

HPT001.016Rev. 4

Page 35 of 66Pre-Job Brief Contents -Radiological (1)

• Review of applicable procedures.

• Dose rates, Contamination levels, etc.

• Access routes to & from work site.

• Areas to be avoided.

• High radiation areas & hot spots.

• Location of low dose rate areas.

• Special radiological limitations/controls

http://www.tva.gov/


TP-36

HPT001.016Rev. 4

Page 36 of 66Pre-Job Brief Contents – Radiological (2)

• Hold Points.

• Stay Times.

• Maximum dose limits.

• Maximum dose rate limits.

• Operating Experience/Lessons learned.

• ALARA goals for the job or task.

• Potential problems & contingency plan

http://www.tva.gov/


TP-37

HPT001.016Rev. 4

Page 37 of 66Pre-Job Brief Contents – General

• What are we going to do?• What is the Worst Thing that could happen?• What are the Critical Steps?• What if Mistakes happen, especially at

Critical Steps?• What are the Error Likely Situations?• What are the Safety Concerns?• Operating Experiences

http://www.tva.gov/


TP-38

HPT001.016Rev. 4

Page 38 of 66Post-Job Briefing –Radiological

• Review factors affecting job performance or exposure.

• Identify problems encountered.

• Review radiological exposures & identify factors leading to increases or decreased from expected.

• Identify corrective actions.

http://www.tva.gov/


TP-39

HPT001.016Rev. 4

Page 39 of 66Post Job Briefing – General (1)

• Any Recommended Changes?

• Any Unexpected Aspects or Occurrences?

• Task Accomplished with Expected Results?

• Any Enhancement to Plant Documentation Warranted?

• Planning & Scheduling Optimized to Reduce Human Errors?

http://www.tva.gov/


TP-40

HPT001.016Rev. 4

Page 40 of 66Post Job Briefing – General (2)

• Was Preparation Adequate?

• Lessons Learned Identified?

• Needed Supervision Support Provided?

• Any Human Factor Issues, Hindrances to Work Observed?

• Training for Job Adequate & Effective?

http://www.tva.gov/


TP-41

HPT001.016Rev. 4

Page 41 of 66

Radiation Exposures

Major portion of radiation exposures from:

• Maintenance

• Radwaste handling

• In-Service inspections

• Refueling

• Nonroutine operations

http://www.tva.gov/


TP-42

HPT001.016Rev. 4

Page 42 of 66

ALARA Program Procedures

• TVAN RCDP-1Sets policy to ensure risks from ionizing radiation are ALARA.

• TVAN SPP-5.2Establishes ALARA Program and outlines responsibilities.

http://www.tva.gov/


TP-43

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ALARA Responsibilities

• Senior VP, Nuclear Operations andVP, Engineering & Technical Services

Establish controls to incorporate:

http://www.tva.gov/


TP-44

HPT001.016Rev. 4

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VPs Establish Controls For:

• Evaluate Design & Design Mods to:- Determine Radiological Impacts- Achieve Cobalt Reduction

• Temporary Shielding Analysis

• ALARA Walkdowns

• Consider Occupational Radiation Doses

http://www.tva.gov/


TP-45

HPT001.016Rev. 4

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Design Functions

• Mechanical Design StandardDS-M18.7.1 Addresses the Concept ofALARA in Plant Design Activities

http://www.tva.gov/


TP-46

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Page 46 of 66

Design Standards Include: (1)

• References to Radiological Requirements of Plant Specific Restrictions or Radiological Technical Specifications.

• Methods to Minimize Source Terms• Control of Fuel Integrity• ALARA Conditions of Reg Guide 8.8• ALARA from Effluent Releases

http://www.tva.gov/


TP-47

HPT001.016Rev. 4

Page 47 of 66

Design Standards Include: (2)

• Radiological Control Impacts ofDesign Changes

• Radiological Impacts Regarding:- Changes in Zoning, Shielding, etc.- Source Term or Chemistry Changes- Other Systems or Adjacent Areas

• Steps to Reduce Impacts of Cobalt

http://www.tva.gov/


TP-48

HPT001.016Rev. 4

Page 48 of 66

Cobalt Reduction

• Use of Low Cobalt Materials for Piping and Equipment in Contact with Primary Coolant.

• Eliminate Use of Cobalt-Containing Materials for Parts or Components of Valves (e.g. Valve Trim, Seats, Pins) in Flow Path to Reactor Core.

http://www.tva.gov/


TP-49

HPT001.016Rev. 4

Page 49 of 66

Impacts on ALARA - 1

• Access Control to Radiological Areas

• Shielding- Labyrinth Entrances for Access- Permanent Shielding- Temporary Shielding

• Instruments & Controls- Location- Remote Operation

http://www.tva.gov/


TP-50

HPT001.016Rev. 4

Page 50 of 66

Labyrinth Shielding

http://www.tva.gov/


TP-51

HPT001.016Rev. 4

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Penetration Shielding

http://www.tva.gov/


TP-52

HPT001.016Rev. 4

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Impacts on ALARA - 2

• Control Airborne Contamination- Maintain Pressure Gradients- Use Filtration

• Control “Crud” BuildupPotential Activation Produces Contributing to Crud Buildup Include:

C0-58, Co-60, Mn-54, Zn-65, & Zr-95

http://www.tva.gov/


TP-53

HPT001.016Rev. 4

Page 53 of 66

Controlling Crud

• Use “Y” Pipe Joints, Not “T” Joints(Laminar Flow)

• Rounding Pipe Bends

• Use of Crud Traps or Filters

• Smooth Welds

• Use of Low Cobalt Materials

• Flush Lines to Remove Crud

http://www.tva.gov/


TP-54

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Desired Radiological Control

• Engineering Controls are Given Precedence over Administrative Controls in Both Facility Design and Operations

http://www.tva.gov/


TP-55

HPT001.016Rev. 4

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Exposure Reduction

• Source Removal or Reduction

• Reduce Exposure Time

• Increase Distance from Sources

• Provide Additional Shielding

http://www.tva.gov/


TP-56

HPT001.016Rev. 4

Page 56 of 66

Source Removal or Reduction

• Replace Filters or “Crud” Traps

• Flush Crud from Piping

• Decontaminate Surfaces

• Isolate Contamination- Glove Boxes- Tents- Confine to a Room or Building- Reduce Resuspension

http://www.tva.gov/


TP-57

HPT001.016Rev. 4

Page 57 of 66

Glove Box?

ENSURE:

Effective

Communications

Self-

Checking

http://www.tva.gov/


TP-58

HPT001.016Rev. 4

Page 58 of 66Contamination ControlWBN 5-Path Drive

http://www.tva.gov/


TP-59

HPT001.016Rev. 4

Page 59 of 66Contamination WithHigh Radiological Risk

Work Activities Include:• Use of Explosives• Grit Blasting, Grinding, Burning,

Welding• Spalling (e.g. Concrete)• Use of Volatile Solvents• Cleaning with Compressed Air• Refueling Work

http://www.tva.gov/


TP-60

HPT001.016Rev. 4

Page 60 of 66Contamination WithModerate Radiological Risk

Work Activities Include:• Mechanical Cutting (e.g. Saw)• Handwork with File or Stone Emery• Hydrostatic Testing• Chemical Cleaning• Decontamination, Damp or Wet• Purging of Contained Systems• Machining (Cutting Tools)

http://www.tva.gov/


TP-61

HPT001.016Rev. 4

Page 61 of 66Contamination WithLow Radiological Risk

Work Activities Include:

• Mechanical Work (Unbolting, Torquing)

• Cleaning, Vacuuming, Housecleaning

• Lubricating (Greasing or Oiling)

• Painting

• Surveillance (Includes Job Scoping andMeasurement)

http://www.tva.gov/


TP-62

HPT001.016Rev. 4

Page 62 of 66

Reduce Exposure Time - 1

• Ensure Adequate Planning

• Ensure Proper Training

• Job Rehearsal

• Use Mockups

• Pre-Fabricate Materials

• Pre-Job Briefing

http://www.tva.gov/


TP-63

HPT001.016Rev. 4

Page 63 of 66

Reduce Exposure Time - 2

• Sequence Work to Remove High Dose Rate Items First.

• Provide Areas of Low Radiation Exposure in RCA.

• Increase Worker Comfort.

http://www.tva.gov/


TP-64

HPT001.016Rev. 4

Page 64 of 66

Increase Distance

• Use Remote Handling Tools.

• Provide Areas of Low Radiation Exposure in RCA.

• Locate Instrumentation & Controls in Low Radiation Exposure Areas.

• Remove Equipment to Low Dose Rate Areas for Maintenance.

http://www.tva.gov/


TP-65

HPT001.016Rev. 4

Page 65 of 66

Temporary Shielding

• Used Only When Other Methods not Practical

• Addressed in SPP 9.4 and SPP 9.5

• Anyone May Request Shielding

• Approved by ALARA Supervisor

• 50.59 Review by Site Engineering

http://www.tva.gov/


TP-66

HPT001.016Rev. 4

Page 66 of 66Temporary ShieldingFactors to Consider

• Cost & Effectiveness

• Dose During Installation

• Personnel & Equipment Safety

• Static Loading on Floor & Components

• Length of Installation

• Interference with Other Jobs

• Prevent Bare Lead Contact w/Nickel

http://www.tva.gov/


TP-67

HPT001.016Rev. 4

Page 67 of 66

Temporary Shielding Removal

• Temporary Shielding Should Never Be Removed Without Proper Approvals!

- May Create Variance from Technical Specifications.

- May Cause Personnel Exposure to High Levels of Radiation.

http://www.tva.gov/


TP-68

HPT001.016Rev. 4

Page 68 of 66

Shielding Applications

• Shielded Pipe Chases

• Mobile Shields near Wall Penetrations

• Lead Brick in Chemistry Laboratory

• Lead Blankets over Piping

http://www.tva.gov/


TP-69

HPT001.016Rev. 4

Page 69 of 66

RVDL Shielding

http://www.tva.gov/


TP-70

HPT001.016Rev. 4

Page 70 of 66

CRD Pump Shielding

http://www.tva.gov/


TP-71

HPT001.016Rev. 4

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Summary - 1

• Required by 10CFR20.1101

• Purpose

• Aims

• Cost-Benefit Analysis

• Societal & Socioeconomic Factors

http://www.tva.gov/


TP-72

HPT001.016Rev. 4

Page 72 of 66

Summary - 2

• Acceptable & Total Risks

• ALARA Committee

• Each Individual Responsible

• Principles to Reduce Exposures

• Engineering Controls take Precedence

http://www.tva.gov/

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TP-1 HPT001.016 Rev. 4 Page 1 of 66 TVAN Technical Training Health Physics (RADCON) Initial Training...

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