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May 10, 1994 |

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DOCUMENT CONTROL CENTER: 1

The attached FAX was received from NEl and|

should be placed in the Public Document Room.i

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. L_John 31. CraigDeputy DirectorDivision of Engineering

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me- I FAX |,

Cover SheetNUCLEAR ENERGY INSTITUTE

To: John Craig |Company: NRC/RES

Phone:Fax: (301)492-3696

From: Kurt Cozens 3Company: NEl H

Phone: (202) 739-8085 &Fax: (202) 785-1898 g

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Date & Time: 05/06/94 08:07 AM w.a

Pages includingcover sheet 6

Comments:

Attached is a sunrnary of the PTS cffort currently being considered by industry. Thisrecomrnendation without these specifics were discussed the NRC Regulatory informttioncor.forence. During our 2 pm conference call today, we would like to discuss this indus:ryproposal and tearn how it would tnesh with other NRC activities We also wish to discussindustry's proposed RPV integrity database

110C05

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NEI RECOMMENDATIONS

PTS ACTION PLAN (ALSO ADDRESSES NON-PTS ISSUES)

- 4 NEAR-TERM ACTIONS '

- 6 LONG-TERM ACTIONS.

- ALL RECOMMENDED ACTIONS WERE BASED ON THEIR ABILITY

- TO APPROPRIATELY ADDRESS KEY TECHNICAL ISSUES

- TO PROVIDE A BASIS FOR THE NRC TO HAVE SUFFICIENTCONFIDENCE THAT THE KEY ISSUES AND THEIRTECHNICAL ASPECTS WILL BE WELL UNDERSTOOD

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|Technical Areas for Concems of Table F-3 - :

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CCAR Define Gomputer Code ecceptance R_equirements so that calculated results are accept-able for probabilistic evaluations. Addresses concem 6 that all evaluations could require I

the use of the same regulatory controlled executable code with no access to the sourcecode for programming and evaluation of viable industry altamatives.

MPFC Define M_ethods for Bant-specificBaw Charactenstics to be used for probabilistic vessel_

integrity evaluations. Addresses concems 5 and 8 that little credit is given to results of ,

vessel examinations that should provide more realistic (less conservative) flaw !characteristics and calculated probabilities. i

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PFTA Define a f,robabilisticBawloierance Approach to assess the need for or benefit of !

mitigative actions. Addresses concems 3 and 4 that a@ce of any c2M* tad valueas the true vessel failure probabilty is very remote and new calculational requirementsthat are not thoroughly evalaated could unnecessanly reduce the allowable fluence

SCTP Define!.creening Enteria Irigger Eoint above which a more detailed asserssdierd of'

uncertainties is warranted. Addresses concems 1 and 2 that decisions on required

mitigative actions cannot be made rationally when trigger point and increased uncertaintyrequirements are not know a priori.

VFRC Defne Messel faliure Bisk criteria by levels of concem, including constituent ranges ofevent frequencies and conditional probabilities. Addresses concem 7 that risk level for

current PTS screening criteria could be reduced by factor of 50 due to arbitraryrequirements on constrtuent parts. :

Imolementation Plans !4

I - Use industry input to formulate industry recommendations'

11 - Use addtional studies to formulam industry recommendations

ill - Use existing information to formulate industry recommendations

Priority Numtws I

1 Absolutely essential for program success

2 - Highly desirable for program success!

3 - Desirablo but not mandatory for program success

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TABLE F-6, NEAR-TERM ACTIONS FOR PTS IMPLEMENTATION PLANS

fitem Action item Tech, impl. Prior- Est.No. Desu% tion Area Plan * ity No, Cost |_

1 Work with the NRC Staff to understand required SCTP 1 2 Luncertsnties for calculatrng RTm (ART in R.G.1.99) per intent of PTS screening critada.

2 Develop position on vessel risk criteria for all VFRC i 1 Levents (HU/CD, PTS, etc.) by considering current

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results from indusby IPFJPRA studies

3 Define recommended list of fracture 4nechanics CCAR ll) 2 Land matsdals topics for further evaluation at

EPRl/NRC sponsored expert's meetings, such as r-claddng and shallow-flaw effects A

4 Prepare input / output specifications for adding MPFC 1 3 L-

resutts of vessel pre- and in-service inspectionsto integratedindustry database

__See Table F-5 for PTS Implementation Plan Legends |

* All implementation Plans (Tables F-8 to F-10) are completed by: 1

"NRC publishes offic!M documentation ofissue resolution."

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TABLE F-7, LONG-TERM ACTIONS FOR PTS IMPLEMENTATION PLANS

ttem Action item Tech. Impt Prior- Est.No. Description Area Plan ity No. Cost

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1a Define a recommended probaixTestic 11aw ider- PFTA 11 1 Hance approach includng the lirtutmg flaw and

|characteristics, fracture mechanics methods, SCTP '

material properties and uixertainty bounds._

1b Deine a recon ~ nended procedure for incorp- CCAR !!! 2 Loratmg recutts of development programs onthermal hydratics, integrated industnrd*hnne and Surveillance programs into theinput to probabilistic PTS evalnations.

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ic Recommend a procedure for using new infor- SCTP 1 2 Lmation to reduce uncertainties and how timsereduced uncertainties can be used to the |advantage of the plant operator.

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2 Define recommended method for defining plant MPFC 11 3 Mspecific limiting flaw chareteristics fromfabrication history and inspection detection and isizing reliabilities and measured results.

3 Recommend requirements for computer codes CCAR 11 1 Hused in probabiEstic PTS. evaluations induding

N procodures and acceptance critana for code

, vafidation and verificaton.

4 Assess need for a total PTS evaluation on a /d 1 3 Ltypica) example pressure vessel with a detailedreport for industry review and comment

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See Table F-5 for PTS Implementation Plan Legends |-_

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HOW ACTIONS ADDRESS TECHNICAL CONCERNS

Action Descriptba Technical Concens Addressede ~_ -

NT-1 Work writh NRC to Understand * DWant on regn.d mitigative acticas cannot _Required Uncertaintics for be made radonally when trigger point andCalculating RTra erART inaear,ed uncatainty are not known a priori.

NT-2 Develop Vessel Risk Critana * Risk Icvel for vessel fategrity screening could bePosition for All Events, reduced by a factor of 50 due to arbitrary limits

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Induding Heatup & Cooldown on <=%t parts.

NT-3 Denne Reen--w List of * Allintegrity evaluations could require the use ofTopics for EPRUNRC Experts' the same NRC controlled coenputer code with noMeetings (eg. Shallow Fisws) capabihty to evaluate viable industry altanatives.

N T-4 Prepare Specificaticar, for a bule credit is given to ruulte of vessel exam-MtA* g fr=~etion Resuhs to

inadcas that con 3d provide more realistic (lessm

Integrated Industry Database conservative) flaw r+=W6 to act limiteLT-ia Dc!Inc Probabilisde Flaw * Ar=*m~ of any calculased value for true vessel

Tulcrance Approach to Aum integrity is very remote and new calculationalthe Need for or BeacGt of requiremcats that are not thorocghly ev=In=tMMitiganvc Actions could i==~~M1y reduce available margins.

* Decisions ce seguired mitigative actions cannot i

be snade radonally when trigger point andinerzased uneettainty are not known a pdori.

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LT-1b Denne Procedure for Use of * All integrity evaluations cock! require the use ofDevelopment Results in Vessel the same NRC controlled computer code with noIntegrity Evaluations '. capability to evaluate viable indmy alternadves.

LT-1c Define Procedure to PMure * Decisions on required mitigative actions cannot.

Uno:rtainties and How to Best be made rationally when trigger point and;

Take Advantage of'nemincreased uneettamty are not known a priori.

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LT-2 Develop Method for Defining Utt!c aedit is given to results of vessel exam-Fisw Characteristics from instions that could provide more realistic (lessPlant / Industry ISI Data

conservative) flaw characteristics to set limits.,

LT 3 Rea sed Procedurcs for * All integrity evaluations could require the use ofVeucI Integrity Code Ver- the same NRC controlled computer code with noification and Validation capability to evaluate viable industry altanatives.

LT-4 Assess Need for Example * Would provide cxample application of recom--

Integrity Evaluation Reportmended methcxis to rddress all concerns above._

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