ML20062A658
| ML20062A658 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 10/09/1978 |
| From: | Justin Fuller PUBLIC SERVICE CO. OF COLORADO |
| To: | Gammill W Office of Nuclear Reactor Regulation |
| References | |
| P-78165, NUDOCS 7810170139 | |
| Download: ML20062A658 (3) | |
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e-y ~ i n PUBLIC SERVICE COMPANY OF COLORADO DENVER, COLORADO 80208 P. O. 80x 840 + ~ J K. FULLER October 9, 1978 Fort St. Vrain v,er m..or,a Unit No. 1 P-78165 Mr. William Gamill Assistant Director for Advan'ced Reactors Division of Project Management {l t U. S. Nuclear Regulatory Commission Washington, D.C.
- 20555, Docket No. 50-267
Subject:
Extension of Cycle 1 Operation Daar Mr. Gammill: The Fort St. Vrain reactor core is designea co operate on a graded fuel cycle and to have about one-sixth of the core rmoved and replaced at planned annual refueling outages. The fuel is designed to reside in the core for six years at full power. During the manufacture of the fuel particles for the initial core, some particles were produced which were clearly.not capable of residence in the core for a full six years. Accordingly, the initial reactor core was loaded in such a manner so as to assure that those particles would be removed after less than six years exposure. In addition, the first refueling was arbitrarily and conservatively scheduled to take place after six months of equivalent full 7 power operation, (150 EFPD), so that refueling outages could be kept on an annual or semi-annual basis. Experience to date has indicated that fuel particle performance has been much better than originally expected, as indicated by the fission product release to the primary coolant. At the present time, the primary coolant circulating fission product inventory is at least a factor of thirty less than the design inventory given in the FSAR and the limit given in Technical Speci-ficattoo LC0 4.2.8. On the basis of The observed fuel particle performance, operation of Cycle 1 beycnd 150 EFPD was considered and found to be acceptable. It was also determined that extension of Cycle 1 operation would not require a Technical Specification change nor did it involve an unreviewed safety question per the guidelines of 10 CFR 50.59. A reconar.dation to extend Cycle 1 operati6n from 150 to 200 EFPD was submitted to the Nuclear Facility Safety Comittee (NFSC) for consideration '78/ ol7 bl31 f ys
- .,,. e 10/9/78
,,,, ;,,,,, 2 Pusuc Scavice CowPAny or Coto naoo o.,e 'P-78165 4 and was accordingly approved on August 3,1978. In accordance with the requirements of Technical Specification LC0 4.1.8, we have attached an approved revised Base Reactivity Curve for your information. It should be noted that the only change to the curve has been to extend it from 3.0X106 MWHr to 4.2X106 MWHr to account for the extended operation of Cycle 1 (4.05X106 MWHr is the equivalent of 200 EFPD). If there are any questions, please let us know. Very truly yours, uller, Vice President Engineering and Planning JKF:ers ( 1 6 6
R n n s. I j; j .7' "p J;j " " """ " - tg.g; g g y l r l if II lh h Approved
- Figure 18 Calculated Base W
Reactivity $frH I k 3,' Chairman, NFSC 1 J
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-0.093 [. d' h k h.[,Q.b { .{-- s 4' I T -4 j -0.092. IL f I v ,,-.} l-,,# 1 {. j. 2 N 1 t.. " f -0.091. q 7 -0.090 I I I I O.0 C.5 1.'0 1.5 2.0 2.5 3.0 3.5, 4.0 4.5 BURNUP, MWH(t) x 106 ._}}