ML20155D757

Informs of NRC Concern Re PTS Ref Temp for Facility Reactor Vessels.Recent Publication by B&W Identify Possible Values for Initial PTS Ref Temp WF-70 Weld Matl in Beltline Region. Response Requested in 60 Days

ML20155D757
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	10/06/1988
From:	Muller D Office of Nuclear Reactor Regulation
To:	Bliss H COMMONWEALTH EDISON CO.
References
NUDOCS 8810110359
Download: ML20155D757 (4)

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• .Eicket filT October 6, 1988 fMC 1 Local'PDRs DDIII-21r/f Occket Nos. 50-295 and 50-304 a Mr. Henry E. Bliss LLuther Nuclear Licensing Manager DD Comnonwealth Edison Company MOM 5 P.O. Box 767 OGC Chicago, IL 60690 hoja

Dear Mr. Bliss:

ACRS (10)

Plant file

SUBJECT:

WF-70 WELD PATERIAL PRESSURIZED THERMAL SH0CK REFERENCE TEMPERATURE This letter is to infonn you of the NRC staff's concern about the pressurized i thermal shock reference temperature (RTpts) for Zion reactor vessels. Zion bessels, and other vessels manufactured by Babcock and Wilcox, contain WF-70 weld material in the beltline region.

At issue is the appropriate value of the initial RTpts for unirradisted WF-70 i material. The Code of Federal Regulations,10 CFR 50.01, specifies that if a {

mes% red initial reference temperature is not available then a generic mean 1 value of 0 degrees F. must be used for the subject material and the margin to account for uncertainties is increased accordingly. The Zior. Updated Safety Analysis Report assures O degrees F. as the initial RTpts. The initial RTpts is used along with accumulated neutron fluence and the uncertainty rargin to compute RTpts during the operating life of the reactor vessel.

Recent publications by Bebcock and Wilcox (BAW-1975 and BAW-1920P) identify possible values for the initial RTpts of WF-70. Although the RTpts measurements conducted to date may not neet the ASME Code criteria for measuring initial RTpts, the test results appear to indicate that the initial RTpts of unirradiated WF-70 may be considerably greater than 0 degrees F.

Hence, it may not be conservative to use O degrees F. as the initial RTpts for WF-70. The test results raise concerns that the sc ;ening criteria may be reached sometime during the projected operation life of the Zion reactors.

These concerns could be resolved by establishing the initial RTpts value for the material in accordance with Peragraph NB-2331 of the ASME Code Section I!!. Within 60 days please aavise Mr. Jan Norris, our project manager for Zion, of your efforts to resolve these concerns.

Sincerely, Daniel F.. Muller, Director Project Directorate 111-2 8810210359 DR 001006 Division of Reactor Projects - !!!

p ADOCK 05000295 IV, V Special Projects PNU cc: See next page q O, L (0 PO!!I- '3 O iPDill-Il

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DISTRIBUTION:

Docket file October 60 1988 NRC & Local PDRs PM II-21 r/f Docket Nos. 50-295 and 50-304 a Mr. Henry E. Bliss LLuther Nuclear Licensing Manager DMuller Cont.onwealth Edison Company P.O. Box 767 fjrris ,

Chicago, IL 60690 "

h0r e

Dear Mr. Bliss:

ACRS (10)

Plant file

SUBJECT:

WF-70 WELD MATERIAL PRESSURIZED THERMAL SH0CX REFERENCE TEMPERATURE inis letter is to infonn you of the NRC staff's concerr< about the pressurized thermal shock reference temperature (RTpts) for Zion reactor ves;els. Zion vessels, and ot' ' vessels manufactured by Babcock and Wilcox, contain WF-70 we tei 1 in the beltline region.

At issue i . , appropriate value of the initial RTpts for unirradiated WF-70 material. ihe Code of Federal Regulations,10 CFR 50.61, specifies that if a measured initial reference temperature is not available then a generic mean value of 0 degrees F. must be used for the subject material and the margin to account for u,1 certainties is increased accordingly. The Zion Updated Safety Analysis Report assumes 0 degrees F. as the initial RTpts. The initial RTpts is used along with accumulated nMtron fluence and the uncertainty n.argin to compute RTpts during the operating life of the reactor vessel.

Recent publications by Babcock and Wilcox (BAW-1975 and BAW-1920P) identify possible values for the initial RTpts of WF-70. Although the RTpts measurements conducted to date may not meet the ASME Code criterie for measuring initial RTpts, the test results appear to indicate that the initial RTpts of unirradiated WF-70 may be considerably greater than 0 degrees F.

Herice, it may not be conservative to use 0 degrees F. as the initial RTpts for WF-70. The test results raise concerns taat the screening criteria may be reached sometime during the projected operatio1 life of the Zion reactors.

These concerns could be resolved by establishing the initial RTpts value for the materidl in accordance with Paragraph NB-2331 of the ASME Code Section III. Within 60 days please advise Mr. Jan Norris, our project manager for Zion, of your efforts to resolve these concerns.

Sincerely, e

l Daniel R. Muller, Director I Project Directorate III-2 l Division of Reactor Projects - III IV, V Special Projects cc: 3ee nev.t page

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[ c UNITED STATES 8' i NUCLEAR REGULATORY COMMISSION g  : E W ASHINGTON, D. C. 20555 October 6, 1988

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Docket Nos. 50-295 and 50-304 Mr. Henry E. Bliss Nuclear Licensing Manager Cormonwealth Edison Company P.O. Box 767 Chicago, IL 60690

SUBJECT:

WF-70 WELD MATERIAL PRESSURIZE 0 THERMAL SH0CK REFERENCE 1%PERATdRE This letter is to inform you of the NRC staff's concern about the pressurized thermal shock reference temperature (RTpts) for Zion reactor vessels. Zion vessels, and other vessels manufactured by Babcock and Wilcox, contain WF-70 weld material in the beltline region.

At issue is the appropriate value of the initial RTpts for unirradiated WF-70 material. The Code of Federal Regulations, 10 CFR 50.61, specifies that if a measured initial reference temperature is not available tiien a generic mean value of 0 degrees F. must be used for the subject material and the margin to account for uncertainties is increased accordingly. The Zion Updated Safety Analysis Report assumes 0 degrees F. as the initial RTpts. The initial RTpts is used along with accumulated neutron fluence and the urn:ertainty margin to compute RTpts during the operating life of the reactor vessel.

Recent publications by Babcock and Wilcox (BAW-1975 and BAW-1920P) identify possible values for the initial RTpts of WF-70. Although the RTpts measurements conducted to date may not meet the ASME Code criteria for measuring initial RTpts, the test results appear to indicate that the initial RTpts of unirradiated WF-70 may be considerably greater than 0 degrees F.

Hence, it may not be conservative to use O degrees F. as the initial RTpts for WF-70. The test results raise concerns that the screening criteria may be reached sometime during the projected operation life of the Zion reactors.

These concerns could be resolved by establishing the initial RTpts value for the material in accordance with Paragraph NB-2331 of the ASME Code Section III. Within 60 days please advise Mr. Jan Norris, our project manager for Zion, of your efforts to resolve these co'ncerns.

Sinc ely, fLV/N w Daniel R. Muller, Director Project Directorate III-2 Division of Reactor Projects - III IV, V Special Projects i

cc: See next page

Mr. Henry E. Bliss Connonwealth Edison Company Zion Station cc:

Robert J. Vollen Esquire Mr. Michael C. Parker, Chief 109 North Dearborn Street Division of Engineering Chicago, Illinois 60602 Illinois Department of Nuclear Safety Dr. Cecil Lue-Hing 1035 Outer Park Drive, 5th Floor Director of Research and Development Springfield, Illinois 62704 Metropolitan Sanitary District of Greater Chicago 100 East Erie Street Chicago, Illinois 60011 Phillip Steptoe, Esq.

Sidley and Austin One First National Plaza Chicago, Illinois 60603 -

Mayor of Zion Zion, Illinois 60099 Illinois Department of Nuclear Safety ATTh: Manager, Nuclear Facility Safety 1035 Outer Park Drive 5th Floor Springfield, Illinois 62704 U.S. Nuclear Regulatory. Commission Resident Inspectors Office 4

105 Shiloh Blvd.

Zion, Illinois 60099 Regional Administrator, Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 t

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