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Nuclear Materials Research at the Westinghouse Hot Cells:

Supporting Fleet Operations for 40 Years

Paula FreyerFellow Engineer

Materials Center of Excellence

Westinghouse Electric Company LLC

NSUF Users MeetingTuesday, June 23, 2015

A Proud NSUF Partner Laboratory


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Westinghouse Laboratories - Areas of Expertise• 40 yrs experience in shipping, handling and evaluating

activated/contaminated materials/components• Mechanical performance testing and microstructural

characterization• Autoclave facilities for comprehensive corrosion

evaluations• Irradiated property measurements• Custom design/fabrication of irradiated materials

testing hardware/loops

2013-15 AP1000 Surveillance Capsule Fabrication

1960s Surveillance Capsule Fabrication

16 new capsules shipped to China

16 new capsules shipped to VC Summer 2 & Vogtle 3

16 new capsules fabricated for VC Summer 3 & Vogtle 4

• Nuclear materials R&D and technology/product development

• Fuel crud and steam generator sludge analysis

• Reactor pressure vessel surveillance capsule design, fabrication and testing

• Irradiated component failure analysis

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Westinghouse Hot Cells

• One of only 3 commercially available hot cell facilities available in the US

• Evaluation of materials with atomic numbers 1 through 96

• 5 hot cells• Multi-functional, routinely re-

configured to meet the needs of each specific program

• High and Low Level cells built in 1975 – have operated continuously since opening

• A and M cells built in 1994

• Extensive complimentary facilities/capabilities

High Level Cell - 1976

Today

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Westinghouse Hot Cells

•In-cell:• cutting, grinding, milling, machining• tensile, Charpy, fracture toughness, slow

strain rate and fatigue testing• metallography and scanning electron

microscopy• ultrasonic and eddy current measurements• welding• dimensional and density measurements• hydrogen analysis

Low level hot cell (left) and high level hot cell (right)

A and M hot cells

*SEM hot cell not shown


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Additional Key Facilities

Corrosion Laboratory

• 22 fully automated autoclaves– 34.5 MPa (5,000 psi) and

482°C (900°F)

– 4 with load frames with capabilities up to 2,720 kg (6,000 lbs)

• Numerous specimen geometries and autoclave conditions utilized

• Corrosion, wear, SCC initiation, and SCC growth

Materials Performance and Characterization Laboratories

• Metallography

• Scanning electron microscopy

–4 SEMs including dual beam FIB, XEDS, EBSD, ‘ultra-hot’ SEM, large chamber

• Scanning transmission electron microscopy

–FEI CM30, 300 KV, LaB6, XEDS

• Auger electron spectroscopy

• X-Ray Diffraction

–micro-diffraction and residual stress measurements

• Full analytical chemistry facilities

–GC, UV-VIS, FTIR, TGA, Raman, IC, ICP-MS, microwave digestion

• Mechanical testing

–multiple frames (100,000 lbs)

Custom Testing Facilities

• Advanced Fuel Crud Deposition Test Loop

• LOCA Debris Blockage Test Facility

• Thermal Hydraulic Testing High Bay

• Zinc Effects Test Loop

• Wear Test Rig

• High Temperature Steam Oxidation Unit

• Reactor Coolant Pump Seal Testing Laboratory

• Laser Welding Facility

Routinely design and fabricate unique testing facilities for our customers

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LOCA Debris Blockage Test Facility

Examples of Unique Capabilities

High Temperature Steam Oxidation Unit

Reactor Coolant Pump Seal Testing Laboratory

Core Inlet Blockage Intermediate Test Loop(under construction)

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Laboratory Customers and Hot Cell Services

• Westinghouse Product Lines• Operating Plants Business• New Plants and Major Projects• Nuclear Fuel and Components

Manufacturing• Decommissioning, Decontamination and

Remediation• Westinghouse Subsidiaries and Affiliates• US and International Utilities• US and International Universities• US and International Laboratories• EPRI• DOE and DOD• PWROG• International Organizations (e.g.,

International IASCC Advisory Committee)• Other commercial organizations,

manufacturers, etc.

• Laboratory facilities originally established to meet Westinghouse needs

• Today, wide range of ‘outside’ customers

• From ‘dirty’ failure analysis work to advanced R&D

• NSUF Partner Laboratory since July 2013

• Available for program collaborations and materials/specimen processing

MissionProvide experimental evidence

to support materials and processing solutions for our

customers and to support industry technical initiatives.


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Wide Range of Hot Cell Evaluations

• Small to large programs• Rapid turn-around (few days) to

multi-year• 24/7 coverage for emergency

evaluations• Wide range of customers• Vast diversity of

components/specimens for study, inspection and testing/evaluation

• Commercial reactor components• Test reactor irradiated components• Tiny parts/pieces to large

components• High radiation level and/or high

contamination level

In-Cell Inspections of Commercial PWR Baffle

Bolt

In-Cell Crack Growth Rate Test Assembly

In-Cell Ultrasonic Measurements of

EBR-II Highly Irradiated 304

Stainless Steel


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In-Cell Eddy Current Examination of ~800 lb Retired Reactor Head Segment with Full

Penetration

Specimen Machining

Three Examples…Hot Cell Projects*

In-Cell Irradiated Charpy Specimen Reconstitution

1. Failure Analysis

2. Effect of Service Exposure on Materials

3. Fundamental Science Evaluation

* Contract hot cell work for a

variety of outside customers

Specimen from PWR Baffle Plate - In-Cell Fracture Toughness

Machining and Testing -

a

cb

a

b

c


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Three Examples…Studies of Highly Neutron Irradiated Stainless Steels

Dose rates@ ~0.5” (R/hr) dpa ranges

>5,000 ~20 – 25

~1,000 ~0 – 80

~1,500 ~0 – 35

Description

1. Highly irradiated 347 SS baffle bolts from a commercial PWRa

2. Highly irradiated 316 SS flux thimble tubes extracted from 3 commercial PWRsb

3. Highly irradiated 304 SS neutron reflector hex blocks from EBR-IIc

Reference Point: Lethal Dose - LD50/60 ~350 R

a “Examination of Baffle-Former Bolts from D.C. Cook Unit 2,” 16th International Conference on Environmental Degradation of Materials in Nuclear Power Plants, Aug 11-15, 2013, Asheville, NC, in press.

b “Hot Cell Crack Initiation Testing of Various Heats of Highly Irradiated 316 Stainless Steel Components Obtained from Three Commercial PWRs,” 13th International Conference on Environmental Degradation of Materials in Nuclear Power Systems 2007 Apr 19-23, Whistler, British Columbia, Canada.

c Extensively published and presented in 2012-2015 (see next slide for partial publication list)

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Highly Irradiated DOE/EBRII ‘Hex Blocks’

• Work extensively published with additional papers currently being prepared

• For detailed technical information, please see (among others):

• Ultrasonic NDE for Irradiation-Induced Material Degradations, Isobe, Etoh, Sagisaka, Matsunaga, Freyer, Garner and Okita, 21st International Conference on Nuclear Engineering, Jul 2013.

• Void Swelling and Resultant Strains in Thick 304 Stainless Steel Components in Response to Spatial Gradients in Neutron Flux-Spectra and Irradiation Temperature, Garner, Freyer, Porter, Wiest, Knight, Okita, Sagisaka, Isobe, Etoh, Matsunaga, Huang and Wiezorek, Proceedings of 16th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, Asheville, NC, Aug 2013.

• Development of a Nondestructive Inspection Method for Irradiation-Induced Microstructural Evolution of Thick 304 Stainless Steel Blocks, Etoh, Sagisaka, Matsunaga, Isobe, Garner, Freyer, Huang, Wiezorek and Okita, Journal of Nuclear Materials, Sept 2013.

• Using UT to Assess Neutron-Induced Damage, Isobe, Etoh, Sagisaka, Matsunaga, Freyer, Garner and Okita, Nuclear Engineering International, April 2014, 36-39.

• Transmission Electron Microscopy of 304-Type Stainless Steel after Exposure to Neutron Flux and Irradiation Temperature Gradients, Wiezorek, Huang, Garner, Freyer, Sagisaka, Isobe and Okita, Microscopy & Microanalysis, Hartford, CT, Aug 2014, pp 1822-1823.

• Measurement of Depth-Dependent Swelling in Thick Non-Uniform Irradiated 304 Stainless Steel Blocks using Nondestructive Ultrasonic Techniques, Garner, Okita, Isobe, Etoh, Sagisaka, Matsunaga, Freyer, Huang, Wiezorek and Porter, Fontevraud 8, Avignon, France, Sept 2014.


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1. Failure Analysis - Background

• Fall 2010 refueling outage – baffle former bolt pieces found on D.C. Cook Unit 2 lower core plate

• Critical lab response during commercial plant outage (24/7 coverage)

• Failure evaluations: bolts, bolt pieces (heads and shanks) and lock bars delivered to Westinghouse Hot Cell

• Intact bolt examinations

Initial In-Cell Visual Inspections of As-Received Components

Sectioning and Metallography of Highly Activated Components

Examples of As-Received Components

Intergranular IASCC on Failed

Baffle Bolt


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1. Failure Analysis – Response and Results

Failed Bolt Evaluations:•Non-destructive evaluations (VT)

•Cross-sectional metallography/light optical microscopy

•SEM fractography•Hardness testing•Chemical analysis

Intact Bolts Evaluations:•Non-destructive evaluations (VT, PT, UT)

•Cross-sectional metallography/light optical microscopy

•Hardness testing•Chemical analysis•Tensile loading

Identification of Failure

Mechanism(s)

Support Apparent

Cause Analysis

Support Justification for

Return to Operation

• Funded by utility• Rapid turn-around response required


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2. Effect of Service Exposure on Materials - Background• Components removed from operating

reactors• Real behavior • Neutron irradiated = depth of

penetration machine realistic sized specimens for relevant data generation

• Study of materials structure and properties after known service exposure• Key property measurements (e.g.

tensile, slow strain rate, IASCC initiation)

• Correlate with microstructural changes

• Provide the mechanisms and database for following and predicting plant internals aging

In-Cell Machining of ~104 Test Specimens from Thimble Tubes Then Testing to Obtain Real

Performance Data

Highly Irradiated Flux Thimble Tubes Removed

from 3-Different Commercial Plants


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Finished O-ring ready for autoclave testing (shown

attached to a split mandrel)O-ring edge being machined down to target length using carbide cutting tool on lathe

ObjectivesDevelop a property database for the 3 heats of material, comprehensive analysis of this test data, and development of predictive equations for the forecasting of IASCC as a function of stress, dpa and material heat.

Complex Scope• dpa profile determination (plant-specific

transport calculations)• Tensile (18)• Slow strain rate (9)• O-ring crack initiation tests (76)• Detailed ANSYS 3-D FE stress analysis of

the O-ring specimen geometry and test loading conditions

• In-depth microstructural characterization

Six O-rings loaded into fixture for subsequent IASCC initiation testing under PWR simulated environmental conditions

2. Effect of Service Exposure on Materials – Program Objectives & Scope

• Funded by 10-member international consortium (International IASCC Advisory Committee)

• ~3 year program


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104-data point O-Ring IASCC database has led to the largest IASCC crack initiation database world wide for highly irradiated

stainless steels

• Crack initiation portion of the scope: 80% of specimen failures occur rapidly, i.e., within ~150 hours (6 days)

• Suggests that under adequate stress, crack initiation in sufficiently irradiated materials will occur rapidly

• Apparent ‘stress threshold’ controlled by irradiated yield strength: saturates by ~ 26 dpa

• No significant effect of material heat

• Applicability of results: predict IASCC behavior in highly irradiated stainless steels (i.e., reactor internals)

• This type of relevant property data: basis for Plant Life Extension technology

2. Effect of Service Exposure on Materials – Results & Implementation


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#3

#5

• Swelling of 304 SS neutron reflector hex blocks from EBR-II exposure

• US-Japan program conducted with:• The Ministry of Education, Culture, Sports,

Science and Technology (MEXT)• University of Tokyo• Nuclear Fuel Industries Ltd.• Radiation Effects Consulting• Idaho National Lab• Westinghouse Hot Cell• University of Pittsburgh & University of Wisconsin

• Objectives:• Quantify irradiation-induced microstructural

changes in thick section austenitic stainless steels as a function of dpa and Tirr

• Support Japanese development of nondestructive inspection technique to measure same above changes

3. Fundamental Science Evaluation - Background

~8

.5”

As-Received Hex Blocks

In-Cell Dimensional Measurements to Quantify Physical Distortion due

to Swelling

• Funded by MEXT• ~9 month program

~1 to 35 dpa


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• Detailed non-destructive UT:• ~25,000 UT data scans!

• Detailed destructive characterization:• Dimensional swelling measurements

• Precise sectioning of into >225 sub-sections

• Immersion density

• Machining to obtain appropriate surface finish and obtain flat and parallel surfaces

• Custom design and build of immersion density equipment for hot cell measurements of ~ 1 lb coins

• ICP-MS chemical analysis

• Metallography, GS

• Shear punch tests (specimen prep)

• TEM characterization of 14 material conditions (~75 high quality foils)

• Void/precipitate/dislocation/loop densities

3. Fundamental Science Evaluation - Techniques

Two of Several Coins Precision Cut from

Blocks

Immersion Density Set-up for Large Coins

Voids of 1-10 nm


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3. Fundamental Science Evaluation - Key Results

Note: 3.2% swelling maximum determined ultrasonically

Extensive in-cell sectioning and immersion density measurements of

high dose coins to determine swelling of individual pieces

Believed to be the most comprehensive ultrasonic evaluation AND microstructural characterization ever performed for highly

irradiated 304 stainless steel.


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• Key characterization of swelling under known service conditions in thick components• Complex distribution of swelling observed

• Material shows maximum of ~ 3% swelling

• Exceptionally sensitive UT data successfully obtained in-cell• Ultrasonic techniques demonstrated to be a

valid method of measuring average void swelling across thick components

• Development of an in-situ measurement tool appears to be possible

• TEM and immersion density agree well with anticipated swelling distribution

• Basis for analysis of commercial plant exposed samples, etc.

3. Fundamental Science Evaluation - Findings and Implications

Key enabler in delivering the results of this complex multi-national program ……

The Westinghouse Hot Cells are now a proud NSUF Partner Laboratory!


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Current Activities – Precision Machining of Hex Blocks for INL

• Contract for INL/Sebastien Teysseyre

• Same highly irradiated EBR-II hex material (~35 dpa)

• Modified 1/4T CT specimens: currently machining practice trials with new milling machine

• In-cell welding of 4 leads per CT specimen

• 2 round tensiles and 4 thin plates for subsequent microscopy are completed

First fabrication of CT specimens with crack propagation through known swelling gradients

Machining of EBR-II Hex Block Materials for Crack Growth Studies of Heavily Voided Microstructures

Thank you to our customer, Sebastien Teysseyre of INL, for permission to discuss this work.


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1.19”

3F3-T 3F3-B

63 mR/hr at 12”(~ 9 R/hr at 1”)

61 mR/hr at 12”(~ 9 R/hr at 1”)

Tensile Specimens Completed


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Practice Machining Trails on Unirradiated Material Outside of Cell Using New Milling Machine for Modified 1/4T CT Specimens


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Four (4) Modified 1/4T CT Specimens After Machining Completed


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Machining completed on four modified 1/4T CT specimens.

Welding of leads onto specimensis on-going.

Machining of EBR-II Hex Block Materials for Crack Growth Studies of Heavily Voided Microstructures

63 mR/hr at 12”(~ 26 R/hr at 1”)


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Dose Rates on Final Machined Specimens

Note a: Measured at 24" using Bicron Surveyor 2000 MeterNote b: Measured at 12" using Thermo Scientific Teleprobe FH 40Note c: Calculated from 24" measured value using

http://www.radprocalculator.com/InverseSquare.aspxNote d: Calculated from 12" measured or calculated values using

http://www.radprocalculator.com/InverseSquare.aspx


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Current Activities – Canadian Nuclear Laboratories, Chalk River

Focused Ion Beam (FIB), Electron Backscatter Diffraction (EBSD)* and Transmission Electron Microscopy (TEM) of Highly Irradiated

Inconel X-750 Spacers from CANDU Reactors

* Because the FIB milled specimens were thin, transmission EBSD, or more accurately, transmission Kikuchi diffraction (TKD) was used to collection the patterns.

• Work is on-going but nearing completion

• Four (4) specimens of highly irradiated material (~65 dpa)

• Preliminary results required 25 working days after specimen receipt at Westinghouse Laboratories

• Each FIB specimen to contain a grain boundary (GB)

• TEM analysis includes characterization of:

• cavities (i.e., He bubbles), dislocation loops, and precipitates at GBs/within grains

• quantitative size distribution of cavities at GBs/within grains• quantitative density determination for cavities at GBs/within grains• qualitative description of chemistry/phase distribution • denuded zone width• GB misorientation

Thank you to our customer, Malcolm Griffiths of Chalk River, for permission to discuss this work.

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29


Location of FIB prepared specimen for first of four as-received samples

Low magnification electron induced secondary electron image

Ion induced secondary electron FIB channeling contrast image


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Under focused bright field TEM image of a grain boundary and surrounding

region from sample GS4 1:00


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Experimental quantitative results to be used as inputs to cavity model(s)

developed by ORNL


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Role of Materials and Hot Cell Laboratories in Commercial Technology

Westinghouse relies on a high level of knowledge of the behavior of irradiated

materials to support the industry

Irradiated Materials’ Structure and

Properties• Measure material properties• Characterize microstructure

after irradiation exposure

Establish Industry Database

• Industry assessment of materials degradation

• Update of potential for failure

• FMECA (failure mode, effects and criticality analysis) assessments

Aging Management Guidelines• Industry proposal for informed

guidelines• NRC acceptance of guidelines – criteria

and thresholds• License renewal inspections and

evaluations, planning and recommendations

Irradiated Component Structure and Property

• Component failure analysis• Remaining margin

assessment• Surveillance programs

Plant Aging Management Support• Development of plant

relicensing support plans• Response to NRC RAIs

(requests for additional information)


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Understanding Irradiated Materials Behavior – Applications to Reactor Vessel Internals

Understanding “scientific effects” provides the basis for interpreting commercial plant operating

experience and developing guidelines

?


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Considerations for Basic Science and Technology Development

• Development of industry relevant positions call for the continued development of basic mechanistic understanding

• Experimental efforts call for dedicated laboratory facilities to evaluate irradiated materials

• Westinghouse has in-place facilities to support development of quantitative data characterizing irradiation effects on plant relevant materials

• Sharing of knowledge is necessary to develop open, reliable and scrutinized positions

• Participation in development of the basic knowledge base directly supports participation in future industry relevant technology programs

– Westinghouse participation in collaborative or sponsored programs continues to build the knowledge base to support our largest customer, commercial nuclear power plants

Westinghouse Laboratories established to support commercial industry initiatives but we also heavily support “basic knowledge programs” for numerous

non-commercial customers


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Schedule and Costs• Hot cell work: ~ 5 to 10x as long as work outside

of cells (depending on complexity)• Time is money: hot cell work costs 5 to 10x as

much as work outside of cells (depending on complexity)

• Include ‘risk’ in your cost and schedule – something almost always goes wrong/breaks/is delayed

Lessons Learned

Document What You Do• Document everything you do in writing in a note book with dates, issues,

raw data results, etc.• Take photographs (we take hundreds) as work progresses – invaluable in

report to customer and/or to review years later • Include a familiar scale in your photographs – a ruler, a dime, etc.


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Hot Cell (and Outside of Cell) Equipment• Always use calibrated equipment – must

know that measurements are correct!• Difficult to find hot cell ready equipment

(generally, cost is high and only partly satisfies our needs) – we buy standard equipment and custom modify it ourselves for hot cell use

• Understand the limits of your manipulators

• can’t open a zip lock bag• limits on how high/low manipulators

can reach• limited manipulator gripping force

and limit on lifting (weight) capability

Lessons Learned


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Hot Cell (and Outside of Cell) Equipment (continued)• Make good use of in-cell cameras

connected to outside cell video monitors to get a close up view of work being done (because your eyes are always a minimum of ~5 feet away depending on your cell window thickness)

• Cheap disposable cameras• Shielding equipment in-cell so it lasts

longer (i.e., cameras)• Use pneumatics and hydraulics as

opposed to mechanical rotation/movement (i.e., pneumatic vice) - saves wear and tear on wrists and manipulators

Lessons Learned


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Communication and Valuable Test Material• Communicate with Radiation Safety Office

and/or Radiological Safety Organization – you need their support for work to progress smoothly

• Excellent communication with your customer required to not waste valuable test material and expensive hot cell labor hours

• Practice trials and/or mockups outside of cell and then practice trials inside of cell using ‘junk’ material is very important!

Lessons Learned

General but Important!• Include radiological disposal costs• Mixed waste – extremely expensive to dispose of - minimize generation and

include costs to get rid of it!


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• Extensive expertise in testing and evaluations of irradiated materials

• Proficiency in one-of-a-kind, first-of-a-kind testing and evaluations

• Three examples of completed programs in hot cell testing of highly irradiated stainless steels

• Two examples of current programs• Critical importance of generating relevant

test data on components removed from actual reactors

Thank you for your attention and….

Summary

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And We Do It All Safely - ALARA

NRC Yearly Whole Body Limit = 5 R

Westinghouse Yearly Whole Body Limit = 500 mr

Current background field in our Hot Cells ~ 1,000 R/hr

with specific areas/components ~ 5,000 R/hr

Westinghouse Hot Cells have been in continuous operation for nearly 40 years and have completed approximately 800 hot cell jobs –

we have never had a ‘stop work event’.

Site: >15 years without a lost time incident.

Attributed to our excellent safety practices and the exceptional skills of our staff.

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