ML17254A695
| ML17254A695 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 12/20/1985 |
| From: | Kober R ROCHESTER GAS & ELECTRIC CORP. |
| To: | Lear G Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17254A696 | List: |
| References | |
| NUDOCS 8512310224 | |
| Download: ML17254A695 (4) | |
Text
REQULATO INFORNATION DISTRIBUTION'EN (RIDS)
ACCESSION NBR: 8512310224 DOC. DATE: 85/12/20 NOTARIZED:
NO DOCKET 0 FACIL:50-244 Robert Emmet Qinna Nuclear Plant>
Unit ii Rochester Q
05000244 AUTH. NANE AUTHOR AFFILIATION KOBER> R. W.
Rochester Qas 5 Electric Corp.
RECIP. NAI'fE RECIPIENT AFFILIATION LEAR> Q. E.
PWR Prospect Directorate
SUBJECT:
Forwards "RE Qinna Containment Vessel Tendons> Review) of NRC SERi" in response to 850819 SER re surveillance program>
results of 1985 tendon surveillance 8c Rev 1 to "Repair of Tendon V-75 for RE Qinna Nuclear Poeer Plant'Repair Rept. "
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zzzztz (zzizssiz III/I///1 /ilSZru ROCHESTER GAS AND ELECTRIC CORPORATION o 89 EAST AVENUE, ROCHESTER, VEV ~ aM eel ~ 8K.:: N.K 14649.0001 ROGER Wi KOBER VICE PRESIDENT ELECTRIC dt STEAM PIIODVCTION TELEPHONE AREA CODE TId 546-2700 December 20r 1985 Director of Nuclear Reactor Regulation Attention: Mr. George E. Lear( Chief PWR Project Directorate No. 1 U.S. Nuclear Regulatory Commission Washington< D.C. 20555
Subject:
Containment Vessel Tendon Inves R. E. Ginna Nuclear Power Plant Docket No. 50-244 rtpp. Ep 'py PORT Er (e~cmlcllr (I Psp ( (posq) '"rd) Pop RSE ( CdipfrCc p (pEII +Csr() diIOy4) tigation / Ref: (1) "Safety Evaluation Containment Vessel Tendon Surveillance Program" dated August 19f 1985 (2) "Summary of October 17> 1985 Meeting on Containment Vessel Tendon Surveillance Program" dated November 5> 1985
Dear Mr. Lear:
On October 17> 1985> RG6E and its consultant> Gilbert Commonwealth met with the NRC and its consultant> Franklin Research Center (FRC) to discuss recommendations contained in the Safety Evaluation Report (SER) in reference (1). As a result of the meeting> RGSE agreed to provide a formal response to the SER recommendations as a follow-up to the technical presentation given during the meeting. The response is included as Attachment A. The following is a summary of the responses to the four recommendations contained in the SER: (1) RGSE has conducted tendon surveillances at an increased frequency since the retensioning program in 1980. Future surveillances will be conducted at 5-year intervals in accordance with the Ginna Technical Specifications. (2) The stress relaxation tests> including both the number of different heats tested and the number of specimens involved< are adequate. The results were evaluated in detail and were used to establish the 16% Base Relaxation curve and the retensioning ratiosr which have in turn yielded predicted tendon forces that agree very well with the forces measured at the tendon surveillances performed in 1981< 1983 and 1985. The data and methodology continue to provide an effective means of monitoring the tendon forces. Thereforef additional laboratory tests are not needed. 85123i0224 851220 If PDR ADOCK 05000244 P PDR
ROCHESTER GAS AND ELECTRIC C RP. DATE December 20, 1985 Nr. George E. Lear SHEET, NO. (3) The FRC comments on increasing the accuracy of the tendon elongation measurements are not applicable for the lift-offtests. However> past tendon elongation measurements> as recent as the June 1980 retensioning> tend to demonstrate the integrity of rock anchors. (4) The previous calculation for determining tendon force loss due to rock creep was incorrect. However<. the revised value is based on a very conservative calculational model for the rock> and its magnitude still is not large enough to alter the previous conclusion that stress relaxation is the primary reason for the larger-than-predicted tendon losses which occurred prior to the June 1980 retensioning. We are also providing the results of the 1985 Tendon Surveillance. They are included as Attachment B. Questions were asked during the meeting concerning the incident during the 1983 Surveillance which left Tendon No. 75 damaged. The following submittals contain information relative to the incident: (1) Letter from Mr. J. E. Maier to Nr. D. N. Crutchfield< dated November 21> 1983. (2) Letter from Mr. R. W. Kober to Mr. D. N. Crutchfield> dated March 26< 1984. In addition, a copy of Inryco report entitled> "Repair of Tendon V-75 for R. E. Ginna Nuclear Power Plant" dated December 29> 1983 is included as Attachment C. RGGE concurs with the staff that (1) all safety concerns have been addressed< and (2) the structural adequacy of the containment vessel is assured. Consistent with the findings in reference (2)i we believe that the containment tendon investigation should be considered resolved. V ry truly yours> ppfu'oger W. Kober}}