ML20206D197
| ML20206D197 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 11/10/1988 |
| From: | Capstick R VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-REGGD-01.099 FVY-88-94, GL-88-11, NUDOCS 8811170006 | |
| Download: ML20206D197 (2) | |
Text
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VERMONT YANKEE NUdLEAR POWER CORPORATION 7
RD 5. Bcx 169. Ferry Road. Brattleboro, VT 05301 ENGINEERING OFFICE 580 M*'u stst cT
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November 10, 1988 BN M A W
'j pyy gg_g4 (506) 779 6711 United States Nuclear Regulatory Comission Attention: Document Control Desk Washington, DC 20555
References:
(a) License No. DPR-28 (Docket No. 50-271)
(b) Letter, USNRC to All Licensees of Operating Reactors and Holders of Construction Permits, hVi 88-144, Generic Letter No. 88-11, dated July 12, 1988 (t i Letter VYNPC to USNRC, FVY 85-46, "Reactor Vessel Pressure / Temperature Curves," dated May 10, 1985 (d) Letter, VYNPC to USNRC, FVY 85-107, "Response to Request for Additional Information Concerning Vermont Yankee Proposed Change No. 129 - Reactor Vessel Pressure / Temperature Curves," dated November 21, 1985 (e) Letter, USNRC to VYNPC, NVY 86-121 Amendment No. 93 to i
Facility Operating License No. DPR-28, dated June 24, 1986
Subject:
Vermont Yankee Response to NRC Generic Letter No. 88-11:
"NRC Position on Radiation Embrittlement of Reactor Vessel Materials and Its Impact on Plant Operations"
Dear Sir:
In May 1988, the United States Nuclear Regulatory Coraission (NRCi issued Revision 2 to Regulatory Guide 1.99, "Radiation Embrittlement of Reactor Vessel Materials," which will be used by the NRC in reviewing submittals regarding Pressure-Temperature (P-T) limits and for analyses that. require an estimate of the embrittlertent of reactor vessel beltline materials.
Subsequently, the NRC issued Generic Letter No. 88-11 (Reference (b)]
t requiring licensees to use the methods described in Revision 2 to Regulatory Guido 1.99 to predict the effect of neutron radiation on reactor vessel materials as required by Para,traph V.A. of 10CFR, Part 50, Appendix G, unless different methods are justif W. The suoject generic letter additionally required licensees to submit the results of their technical analysis, using Regulatory Guide 1.99, Revision 2, and to propose a schedule for any actions necessary to ensure compliance with the revised regulatory guidance. The purpose of this letter is to provide Vermont Yankee's response to the requirements of Generic Letter 88-11.
Vermont Yankee has previously appliea the guidance of Regulatory Guide 1.99, Revision 2 to our f acility (f.ef erences (c) and (d)]. This application was subsequently approved by NRC in Amendment No. 93 to the Vermont Yankee Technical Specifications (Keference (e)], wherein the staff's 00$
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United States Nuclear Regulatory Commission November 10, 1988 Page 2 Safety Evaluation Report states, ir, pertinent part, "The proposed changes to the Technical Specifications.... meet the requirements of 100FR50, Appendix G. Regulatory Guide 1.99, Revisions 1 end 2, and Appendix G.Section III of the ASME Code."
Because Vermont Yankee's submittal and the NRC staff's approval were based on the February 1986 draf t of Regulatory Guide 1.99, Revision 2. Vermont Yankee evaluated the differences between the February 1986 draft and the final version which became effective in May 1988.
The only technical difference between the two versions that applies to Vermont Yankee la the method of predicting radiation-inouced shift of the RTNDT. The February 1966 draft calculates RTNDT as a direct function of depth into the reactor pressure vessel wall. The May 1988 version of Revision 2 predicts fluence as a function of depth and then uses fluence to predict RTNDT.
For Vermont Yankee, the February 1986 draft of Regulatory Guide 1.99, Revision 2, is more i
conservative as shown below:
j February 1986 May 1988 EOL Surface Fluence 2.3 x 1017 n/cm2 2.3 x 1017 n/cm2 ARTNDT(surface) 14.2*F 14.2'F 4RTNDT(1/4T) 13.1'F 11.8'F ARTNDT(3/4t) 11.1'F 7.8'T The language differences in the section concerning use of surveillance data are not significant because the velds are not the limiting component in the Vermont Yankee vessel.
Based on the above. It is concluded that Vermont Yankee has previously predicted the effect of neutron radiation on reactor v61sel materials using the methods described in Regulatory Guide 1.99, Revistor. 2, as required by Generic Letter No. 88-11.
Lecause this analysis was rev.ewed and approved by the NRP in Amendment No. 93 to the Vermont Yankee Techni al Specifications, no fus cher technical analyses or modifications of the P-T 1 mits contained in the Vermont Yankee Technical Specifications are necessary in order to continue to satisfy the requirements of Section V of 10CFR50, Appendix G.
Accordingly, Vermont Yankee proposes no further actions to be taken to ensure compliance with the revised regulatory guiiance provided in Generic Letter No. 88-11.
Should you have any questions or require further information concerning this mattee, please contact this office.
Very truly yours.
VERMONT YANKEE tRl CLEAR POWER CORPORATION Y
J R. W. Capstick Licensing Engineer RWC/25.827 cc USNRC - Region !
USNRC - Resident Inspector, YYNPC
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