acads (08-006) covered keywords beta/gamma contamination, alpha contamination, loose, airborne,...

ACADs (08-006) Covered

KeywordsBeta/gamma contamination, alpha contamination, loose, airborne, fixed, wipe, smear, noble gases, particulate, vapors, hot particles, contamination limits, personnel monitors, loose survey, direct survey, RCA release survey, contamination control, inhalation, ingestion, absorption, personnel contamination protection, personnel contamination detection, plant area decontamination.

Description

Supporting MaterialContamination Control Lesson Plan

1.1.8.4.1 1.1.8.4.2 1.1.8.4.3 1.1.8.4.4 3.2.3.13 3.2.3.23.5 3.2.3.23.6 3.2.3.23.12

3.2.3.28.2 3.3.2.4.1 3.3.2.4.2 3.3.8.7 3.3.8.9 3.3.9.5 3.3.9.8.1 3.3.9.8.5

3.3.9.16 3.3.9.17 3.3.9.18 3.3.9.21 3.3.10.13 3.3.13.3 3.3.13.6 3.3.15.1

3.3.15.2 4.16.1 4.16.2 4.17.1 4.17.2

CONTAMINATION

CONTROL

RWP REQUIRED FORENTRY

“RADIATION AREA”

“CONTAMINATION AREA”

RWP FOR ENTRY

REMOVE ALL ANTI-C ZONE

CLOTHING BEFORESTEPPING HERE

Spills Of Reactor Coolant

Reactor CoolantLeaks

Maintenance Activities

Performed On A System

CONTAMINATION DEFINITION

Contamination - Radioactive material in an unwanted place

MAJOR SOURCESFission Products

Activation ProductsActivated Corrosion Products

Escape piping or components Reactor CoolantCoolant Gases

Activation ProductsFission Products

Boric Acid Corrosion

Defective Welds

Defective Pump

Gaskets Flanged Connections

Valves

TYPES OF CONTAMINATION

Alpha contamination –

Isotopic make-up of the contamination releases alpha

during decay process

Beta/Gamma contamination – Isotopic make-up of the contamination

releases beta and/or gamma during decay process

FIXEDContamination Embedded

In Object Cannot Be Removed Through Normal

Cleaning

AIRBORNE

RADIOACTIVE

PARTICLES OR GASES SUSPENDED IN THE

AIR

LOOSERADIOACTI

VE MATERIALTRANSFER

RABLESMEARABL

EUnits Of Measure

DPM/100 CM2UNITS OF MEASURE

CPM

fORMS OF CONTAMINATION

CONTAMINATION SURVEY TECHNIQUES

Loose Contamination smearable, removable, transferable

Wipe

Chemically treated clothVerify non-contamination

100 ft2 areaFold in route to survey instrument

Frisker monitors for beta/gamma contaminationUnit of measurement cpm


1

SMEARSFrisker or laboratory counter

Frisker 1st

Caution cross-contamination (count area &

counter)Limit on laboratory counter

SMEARSNumber represent total area

Area surveyed – 100 cm2Identify each smear

Avoid cross-contamination

SMEARS - dpm/100cm2Counting inst – cpm

cpm / efficiency = dpmFrisker – 10%

Lab counters – calibrate

Smear > friskerion chamber w/omrem/hr/100cm2


Fixed Contamination – embedded in object

Direct survey – frisker & pancake probe

Contamination indication – audible count rate increasemeter reading increasealarm sounds

Survey technique – slowlytotal area surveyed

transverse indicated area – define boundariesmeasure

Unit of measurement – cpm

Noble Gases

Vapors - IodineParticulate

CONTAMINATION SURVEY TECHNIQUESAirborne contamination – suspended in air

Survey – sampler - draw air into or across media –media counted to quantify amount of radioactivity

Unit of measurement – Ci/cc

Special Type Loose Contamination Definition

HOT PARTICLES

Single discrete particle difficult to see

>0.1 Ci

Activated corrosion product(stellite)

Fuel fragment

Negative charged - Mobilize easily

Beta emitters –High localized skin exposure

HOT PARTICLE SURVEY TECHNIQUE

Hot Particle contamination verified with 1 cm or shielding mechanisms

Hot Particle > or = 20000 cpm

Hot Particle removed with tape & sent for gamma id

Hot particles in area surveyed with sticky media such as tacky roller

CONTAMINATION SURVEYS

Technicians shall:

Adhere to requirements for entry into area

Minimize radiation exposure

Eliminate personal contamination potential

Check all instruments used for proper operationup-to-date calibrationperform source checksassignment to technician in HIS-20

Document survey in VSDS and/or HIS-20

Contamination Limits

Isotopic analysis α determines alpha potential based upon beta/gamma nuclides presentα correlates alpha potential to specific beta/gamma nuclides

Alpha nuclidesα fuel failuresα high internal dose conversion factorsα difficult to measure directlyα gross alpha determines presence and levelsα limits based on internal deposition & stochastic ALI

Beta/gamma : AlphaAlpha contamination levels correlated to beta/gamma contamination levels

Apply ALI of beta/gamma to ALI of alpha50:1 or lower - require alpha monitoring

Beta/gamma : Alpha >50 : 1

No routine plant area alpha surveysNo routine release alpha surveys

Used to set alpha work area surveys based upon beta/gamma levelsUsed to set contamination limits

Alpha – loose 20 dpm/100cm2, direct 30 cpm

Beta/gamma – loose 1000 dpm/1oocm2, direct 100 cpm

LOOSE CONTAMINATION IDENTIFICATION

Object/Item >1000 dpm/100cm2 ()

and/or >30 dpm/100cm2 ()

RADIOACTIVEMATERIAL

PRECAUTIONS

RADIOACTIVEMATERIAL

PRECAUTIONS

(SEE OTHER SIDE)

Identification ____________________________________________

Radiation Level

Gamma_____Mrem/hr at contactGamma_____Mrem/hr at______Beta_______Mrem/hr at contactOther______Mrem/hr at_______

CONTAMINATION LEVEL Location____Smearable/Direct____ Location____Smearable/Direct____

__________________________________________________________Survey By:____ Survey NO:_____Time:_________ Date:__________

Object bagged or wrapped to control

loose contaminationto denote

contentcontamination levelsradiation levelstech performing survey

Radioactive Material Tag (Rad Tag)

Radioactive Material must be stored in a designated location

LOOSE CONTAMINATION IDENTIFICATIONPlant Area

>1000 dpm/100cm2 () and/or

>30 dpm/100cm2 ()

Designate and contain contamination by placing yellow and magenta chain, ribbon, or rope around area

CONTAMINATION AREA

Sign posting on boundaries installed stating“CautionContamination Area”



Step-off-pad (SOP)designate entry/exit pointline of demarcation between Contamination Area & RCA

Proper procedures for crossing observed to prevent spread of contamination.

All items/personnel enter and exit via SOP.

SOP part of barrier

part of non-contaminated RCA



‘Hot Particle’High levels ofContamination

Multiple SOPs

Outer SOP onlyconsiderednon-contaminated

LOOSE CONTAMINATION IDENTIFICATIONPlant Area

>1000 dpm/100cm2 () and/or

>30 dpm/100cm2 ()



CONTAMINATION AREA Items/personnel exiting Contamination Areaconsidered contaminated until surveyed

Items•Surveyed by Radcon verify <1000 dpm/100cm2•Bagged at SOP, sealed, and transported to Radcon

Items >1000 dpm/100cm2•Remain in Contaminated Area•Bagged, sealed, tagged, & stored

PersonnelSurveyed through use of nearest hand-held frisker or automated personnel monitors

Automated Personnel Contamination Monitor

Inside RCA – PCM-1bRCA exits – PCM-1b

PCM-2a

PCM-1b/PCM-2a Beta detecting Proportional monitors

PCM-1b PCM-2a

Detector alarms normally consistent with area contaminated.Hot Particles or high contamination can instigate alarms beyond area contaminated.

PM-7RCA exitsGatehouse exitsFinal check

PM-7“Door frame” type Gamma detectingScintillation monitor

Hand-held Frisker Personnel Monitoring DeviceAutomated Monitor not availablePrecursor to Automated Monitor

Operational ChecksVerify AC (battery if no AC)Verify volume high (to right)Verify on X1 scale (to right)Verify slow response (down)Verify background <300 cpmDetermine background

Proper Technique•Probe detector window ½” from body•Probe movement slow 1-2”/ sec•Consistent movement no area missed

Contamination IndicationAudible count rate increaseAlarm above preset limit audible & visualMeter display increase

>100 cpm above bkg

Non-contaminated - <100 cpm above background

Direct Surveys FixedObjects <1000 dpm/100cm2 loose

Non-contaminated<100 cpm

Items >100 cpm beta/gamma•Marked with magenta paint or tape•Remain inside RCA

Items exceeding the limits set forth in 10CFR20.1094 will be labeled/tagged unless exempt in 10CFR20.1905.

All Radioactive Material will be stored in a designated location.

RCA Release Surveys

All personnel and items exiting RCA to “clean” area require surveys for non-contamination verification for release for non-restricted use.

Personnel Automated Personnel Monitor with preset alarms limits

Items used in RCA onlyProcess through Small Article

Monitor with preset alarm limits

Items from Contamination AreaSurveyed by Radcon “Clean release” results <1000 dpm/100cm2, <100 cpm <20 dpm/100cm2, <30 cpm)

Bulk items/liquidsGamma ID Surveys:•Loose contamination•Fixed contamination

Contamination Control

Contamination - Radioactive Material in unwanted place

Origin – fission & activation products from core & coolant

Cause – release of fission/activation products from system

Control – locate, stop/contain, limit spread, protect/monitor

Control ContaminationPin point the sourceInspect/survey ASAPReview historyReview activitiesGamma ID’sSource undetermined

Stop the releaseImplement site procedures

Control & limit spreadCease releaseContain releaseConfine releaseClean-up releaseConduct surveys

Conduct surveys•Frequent identifies unknown release quickly•Routine controls existing barriers

Control & limit spreadCease release

Contain release•Catch containments•Glove bags•Drain hoses•Absorbents

Confine release•Confinement benefits

×Reduces exposure potential×Eases task of control×Enhances clean-up

•Confinement mechanisms×Isolate with barriers×Control access×Direct traffic flow×Monitoring stations×Protective clothing in area×Items from area surveyed×Clean-up

Clean-up release

Control ContaminationPin point the sourceInspect/survey ASAPReview historyReview activitiesGamma ID’sSource undetermined

Stop the releaseImplement site procedures

Control & limit spreadCease releaseContain releaseConfine releaseClean-up releaseConduct surveys

Protect & monitor personnelBarriersRequirements and guidanceSurveys and monitoring devices

Contamination Control

Contamination - Radioactive Material in unwanted place

Origin – fission & activation products from core & coolant

Cause – release of fission/activation products from system

Control – locate, stop/contain, limit spread, protect/monitor

Limit – strict procedure adherence limits to existing area

Control loss– lack of cooperation & exceptions to procedures

Control implementation – measures for systems breaches

Control Implementation

Cover area - material to be placed over work area

Caution – used around cracks, crevices, small openings

Containment devices – install to contain contamination

Completion – remove/dispose of covers & containments

Clean-up – remove contamination through cleaning process

Personnel Contamination Protection and Detection

Personnel Hazards in a Contamination Area require Protection

InhalationIngestion

Absorption

Contamination on skin/clothing-

Increase potential for internal depositionEfforts utilized to limit personnel contamination/intakes

Extra efforts for areas with break in skinExcess contamination creates radiation exposure

Entry to Contaminated Area requires protective clothing

Personnel Contamination Protection

Entries to Contamination Area controlled with RWP

Protective clothing and devices based upon:Radiological Hazards in areaWork to be performedForm of contamination present (wet, dry, dust, hot particles)Work environment

Low level contamination/Low activity work- Labcoat DressoutLab CoatBootiesOvershoesCotton insertsRubber gloves

Gloves worn whenever potential for hand contamination

REMOVALSEQUENCE

TLD is not removed.

ANKLE STRAPS ANDWRIST CUFFS

RUBBER OVERSHOES

RUBBER GLOVES

CANVAS HOOD

E L E C T R O N I CDOSIMETER

COVERALLS

PLASTIC BOOTIES

COTTON INSERTS (Wearto the frisker. If clean, discard in cleantrash, if contaminated, discard inradioactive waste container incontaminated area)

Normally a “Full Dressout” is required for entry

Personnel Contamination ProtectionHigh contamination levels & Hot Particles require Double Dressout – 2nd set coveralls usually disposable papers, 2 sets of booties, 2 sets of shoe covers, 2 sets of rubber gloves

Wet contamination – Rain-suits

Potential for facial contamination – Dust cups or face-shields

Substantial Airborne contamination – Respiratory devices

Utilize proper steps for donning and doffing clothing

Inspect protective clothing for defects prior to use

Personnel Contamination Protection



Protective clothing removed prior to exiting “Contamination Area” and placed in appropriate reusable or disposable hampers

Reusable- magenta<4500 cpm () - <30 cpm ()

Disposable- yellowprocessed as Radioactive Waste

Smearable <1000 dpm100cm2 <20 dpm/100cm2

Direct <500 cpm <30 cpm

Respiratory equipment -reusable

Proper utilization of SOP – limit spread of contaminationProtective clothing removed prior to SOPTransfer items to/from Contaminated Area at SOPItems surveyed prior to exit or placed in bag at SOP

PERSONNEL CONTAMINATION DETECTION

RWP REQUIRED FORENTRY

“RADIATION AREA”

“CONTAMINATION AREA”

RWP FOR ENTRY



Upon exit Contamination Area proceed to nearest monitoring device

Utilize Automated personnel monitor (PCM-1b) when available – preset alarms <100 cpm

If hand-held frisker is used ensure proper techniques with results <100 cpm

Alpha direct results <30 cpm

Results >100 cpm and/or >30 cpm Require decontamination & documentation

Decontamination – Plant Area

Review work area configuration, radiological conditions, and desired outcome to determine mechanism used

Performed with cleaning solutions, water, rags, and/or mops

Mechanisms for Decontamination of plant areas•Work from boundaries inward reducing as decon is performed•Decon from lowest levels to highest•Fold rag, frequently turn to clean fold, all folds used - change rag •Rinse mop and change water frequently•Detail attention to equipment, cracks, crevices, and difficult places•Ensure all equipment and walls is area are deconned•Items used to decon considered contaminated until surveyed•Place wet items in separate bag after excess water removed

Decontamination – EquipmentNormally in designated facility with use of solution, water, and rags

Notify Radcon prior to start - requirements based on survey results

Equipment decon occurs when >1000 dpm/100cm2 & non-contamination is desired

Need to use caution to ensure equipment not damagedAll parts of equipment need deconned and surveyedAuthorization from owner required to disassemble some equipmentPost decon non-restricted release results -

<1000 dpm/100 cm2, <100cpm

Decontamination - Personnel

Personnel contamination – >100 cpm, 15 cm probe, not noble gas

ClothingSurvey inside and outside clothing

Hot Particle – capture for gamma ID

Decon techniques – tape, water, brushes

Ineffective decon – confiscate clothing, complete form

Complete Personnel Contamination Report

Decontamination - PersonnelSkin – decon ASAP

Capture for gamma IDMedical staff required – ear canal, eye, break in skinAdjacent to skin break – cover breakInjured personnel – surveys/decon secondary

•Minor injuries inside RCA – notify Medical prior to arrival•Off-site medical assistance – future lesson plan (MERT)

WBC required – •Facial contamination indicating intake•Nasal contamination detected•Ingestion of radioactive material•Open wound contamination

Decontamination through soap and waterTape used for capture – caution in areas with hairIneffective decon – sweating used

Decontamination - PersonnelSkin – decon ASAP (cont)

Large area decon – showers•Caution no entry into body opens•Process start at head and progress downward

Hair decon – shampoo & water•Caution no entry to body through openings•Ineffective decon – cut hair – Radcon Shift Supervisor

Notification Radcon Shift Supervisor of difficult deconsTransversal through RCA – containment clothing & pathway survey

•Pathway survey from incident area to monitoring area•Incident area survey may be needed

Complete Personnel Contamination Report, survey documentation, & notify Radcon Shift SupervisorNatural Products & noble gas contaminations not personnel contaminations

Radiation protection work planning and work practice were inadequate.

Managers were aware of the potential for DRPs to be present; however, the magnitude of the dose rates that were encountered was not anticipated.

There was previous plant experience with DRPs in excess of 100 rem per hour when this evolution was performed in 1991, but this information was not widely known, nor was it incorporated into planning for this evolution. The increase in hot particle contamination was attributed to the reduced scope of containment and scaffold decontamination.

Relevant information about hot particles had been omitted from previous post-work ALARA reviews therefore, this information was not incorporated into the incore instrumentation work.

Just-in-Time – Hot Particles Important Points

A radiation protection supervisor determined that the requirements of the hot particle program were not applicable because the definition of a hot particle area was not met, even though it was known that a hot particle existed within the valve for several years.

The assigned radiation protection supervisor did not immediately stop work or urge the workers to leave the area when indication of general radiation levels increased from 15 mrem per hour to 250 mrem per hour.

Contingency plans or actions to be taken if DRPs were encountered in other than controlled areas were not developed.

Turnover to the evening shift occurred while work continued, potentially distracting individuals from receiving needed information. Clear expectations regarding DRP controls for the travel path during the transfer of the ACS were not established.

Just-in-Time – Hot Particles – contContributing Factors

Although workers believed DRPs might be present, a DRP check of the unit was not required by the work package nor was one completed before the transfer of the ACS began.

Because of the ACS design, and the inability to hydrolaze in an upward direction, portions of the unit could not be effectively cleaned.

The ACS was not rinsed with demineralized water as it was raised from the fuel pool as had been the practice in the past to help remove potential DRPs.

The personnel contamination monitors at the RCA exit were relatively insensitive to the higher energy cobalt-60 gamma radiation and may not detect beta radiation if shielded by clothing or in a location of poor geometry relative to the monitor.



Sticky pads were not used as prescribed by procedure.

Less than adequate radiological work practices were identified.

Lack of proper labeling existed at the job site.

Less than adequate planning regarding communication methods when wearing certain protective equipment.

Less than adequate training for identifying the location of special tags and equipment used for hot particles.

What contamination controls should be used when a contaminated piece of equipment is moved?

What is the most effective way to communicate these controls to personnel involved with the task?

What course of action should be taken if hot particles are anticipated?

What course of action should be taken if hot particles are identified?

What controls should be considered prior to retrieving a hot particle?

How do we consider dose, particle movement, and difficulty of removal?

Just-in-Time – Hot Particles – contQuestions

How do we capture radiological lessons learned at the completion of our task?

What are the hazards associated with hot particles?

How do we communicate the potential hazards to those involved?

How do we ensure prejob briefs are sufficiently in-depth and inform workers of the radiological risks associated with the task to

be performed?

Under what conditions do we expect radiological technicians to stop work in the field?

When should a hot particle control zone be established?


When should a check of hot particles be made?

What monitors should be used considering the type of contamination anticipated?

What training is required to support the task if hot particles are anticipated?


acads (08-006) covered keywords beta/gamma contamination, alpha contamination, loose, airborne,...

Documents

contamination limits

contamination control

contamination releases

loose survey

total area area

air survey sampler

decay process slide

smears frisker