ML19254F260
| ML19254F260 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/31/1979 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7911070438 | |
| Download: ML19254F260 (2) | |
Text
,.... A
- SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 s street Box 15830. sacramento. California 95813; (916) 452-3211 October 31, 1979 Director of Nuclear Reactor Regulation Attn
- Mr. Robert W. Reid, Chief Operating Reactors, Branch 4 U.S. Nuclear Regulatory Commission Washington, D. C.
20555 Docket 50-312 Rancho Seco Nuclear Generating Station Unit No. 1
Dear Mr. Reid:
SMUD is participating in the B&W integrated reactor vessel surveil-lance program (IRVSP) with Toledo Edison Company's Davis-Besse Unit 1 (DB-1) serving as the host reactor.
Rancho Seco Unit 1 Technical Specification 4.2.8.2 requires the submittal of a report or an application for license amendment to the NRC any time (beginning one year after DB-l's attainment of comercial operation at 100% power) Davis-Besse 1 fails to maintain a cumulative reactor utilization factor of greater than 65%.
DB-1 achieved 100% power on July 31, 1978. One year later, DB-1 failed to maintain a cummulative reactor utilization factor of greater than 65%. The objective of this report is to address the justification for the continued operation of Rancho Seco with regard to the relatively low DB-1 cummulative reactor utilization factor.
Since the restart of DB-1 following the Three Mile Island incident, DB-1 has maintained a cummulative reactor utilization factor considerably higher than the 65% factor specified.
In the months following its restart, the operating history of DB-1 is similar to that of Rancho Seco.
Therefore, to assess the impact of the relatively low reactor utilization factor, one needs only to address the effects of the previous fourteen months of operations.
At tne end of the current DB-1 fuel cycle a capsule from the RVSP of Rancho Seco will be withdrawn and evaluated.
Table 1 presents the irradiation history of the capsule and the reactor vessel of Rancho Seco, assuming a 0.8 reactor utilization factor for DB-1 and Rancho Seco from the time of this report to the end of the current DB-1 cycle. The accumulated neutron fluence of the capsule corresponds to 8.9 EFPY for the 1/4 thickness location of the reactor vessel of Rancho Seco. At the time of withdrawal and evaluation of this capsule, the total accumulated operation of Rancho Seco will be 3.0 EFPY.
1"?
??0 h
7 91107 0$ 4 3 6 4
.w
a
.,,, c.,
Mr. Robert W. Reid October 31, 1979 Ubviously the fluence of the capsule, as well as subsequent capsules, leads the reactor vessel by a sufficient margin to allow the modification of the Technical Specifi ation pressure-temperature lim.'t curves as necessary to account for irradiation induced changes to the material fracture toughness.
This will insure the continued safe operation of the Rancho Seco Plant.
IRRADIATION DATA FOR RV'S AND CAPSULES FOR IRVSP AT DAVIS BESSE I Taole 1 IDENTIFICATION ACCUMULATED CORRESPONDING APPR0XIMAT-0F CAPSULE TO NUETRON FLUENCE NUMBER OF F" Y ACCUMULATED BE WITHDRAWN OF CAPSULE FOR REACTOR NUMBER OF EFPY AT END OF VESSEL AT THE AT END OF DB-1 2
FIRST DB-1 n/cm hT LOCATION FIRST CYCLE UNIT CYCLE EFPY EFPY AN0-1 ANI-B 3.3 x 1028 8.9 3.5 RS-1 RSI-E 3.3 x 1018 8.9 3.0 08-1 TEI-F 2.3 x 1028 6.3 1.1 If you have any questions or require additional information, please advise.
Sincerely, n[A John J. Mattimoe Assistant General Manager and Chief Engineer cc:
R.H. Engelken NRC, Region V 1')"2 22}