ML19341C786
| ML19341C786 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 09/16/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19341C775 | List: |
| References | |
| NUDOCS 8103040186 | |
| Download: ML19341C786 (2) | |
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'o UNITED STATES
- v. :E E, E,7 NUCLEAR REGULATORY COMMISSION ~
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y SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 34 TO FACILITY OPERATING LICENSE NO. DPR-6 3
CONSUMERS POWER COMPANY I
BIG ROCK POINT PLANT DOCKET NO. 50-155
.l. 0 INTRODUCTION j
By letter dated-August 25, 1980, Consumers Power Company (CPC) (the licensee) recuested an amendment to Facility Operating License No. DPR-6 for the Big Rock Point Plant. This amendment would reinstate the original Low Reactor Water Level -(LRWL) trip setpoint of two feet-nine inches (2'9") above the top i
,0f the active fuel.. Since November 1979, Big Rock Point has been' operating
. with a LRWL trip setpoin'. of three feet-one inch (3'1") above the top of the active fuel.
This change was authorized by Amendment No. 31 to the license -
dated November 2. 1979.
The trip setpoint was increased at that time as a j
Prt of the short tern actions to co-rect the oroblem of ooter.tisi -eference le; #ia7hing in the level measuremen. syster
>e 'icer:see has requested a change i the LRe:L setooint because the % creased vaIve has been found to cause frequer.t alarns and to restrict power operation to 75; of full power at so,w times.
2.0 DISCUSSION AND EVALUATION The 4-inch increase in the -LRWL trip setpoint authorized by Amendment No. 31 was ceemeo necessary to accormiodate the loss of oressure compensation in the
.ievel measurenent system.
Such loss occurred when the instrument jacket anc the heat transfer ciamps., connec.ing the reference leg to the variable leg, were removed.
Sir.:e November 1979, CPC has reviewed the critical safety analyses (large breit and small breat LOCA's) which formed the basis for the low reactor 2:a e-level trip setacint.
As a result of that review, CPC has deterrined i
- nat. the analyses actually use dif ferential pressure, rather tnan pressure cc sensated level, as the reactor trip parameter.
The value assumed in the act1;. sis has.3029 pound 5 oer square inch differential (PSID).
CPC has, i
inerefo e. concluded thct t LR'.L tric setooint consistent with.3029 FSID f f. u: instrument tolerances) would result in a value consistent with the
- lant safety analysis.
The CPC analyses also indicated that a LRWL trio setatin: of 2 feet-9 inches (i.e.
2 feet-8 inches plus 1 inch instrurent
.v erar.cei-is consistent witn tne.3029 PSID assumed in the plant safey a r l' :5 4 ?
,0,1 030 4Ol$to 8
2 We have reviewed the CPC position requesting the revised trip setpoint and we agree that the trip setpoint should be chosen to assure consistency with the plant safety analysis.
' e have reviewed the analysis and agree that a W
trip setpoint consistent with.3029 PSID is' appropriate.
In addition, we nave' reviewed the calculation of the trip setpoint and we agree that the Low Reactor Water.ev31 trip setpoint should be set 13 inches (12 inches plus 1 inch for instrument tolerances) above the lower instrument taps, that is 2 feet-9 inches above the top of the active fuel.
Eased on our review of the' licensee's submittal, we find that the proposed change to the Technical Specifications would allow Big Rock Point to con-tinue to meet the requirements 'of 10 CFR 50.46. and Appendix K to 10 CFR
- art-50.
Therefore, we conclude that the proposed change is acceptable.
3.0 EN'!!RONMENTAL CONSIDERATION
'We have determined that the amendment does not authorize a change in effluent tyces or total amounts nor an increase in power level and will not result in any significant environmental impact.
Having made this determination, we have further concluded that the amendment involves an action which is insjgnificant from_ the standpoint of environmental impact and pursuant to 10 CFR 151.5(d)(4) that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
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C7.CLUSIO"5_
..e navc concluded, based on the considerations discussed above, that:
(1) tecause the amendment does not involve a significant increase in the pre-
-tecility or consequences of accidents previously considered and does not
'nvolve a significant decrease in a safety margin, the amendment does not inv?lve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endanger'ed by operation in the propo:ed manner, and (3) such activities will be con-catted in compliance with the Commission's regulations and the issuance of
- nis amendment will not be inimical to the common defense and security or to tne healtn and safety of the public.
, sa:e:
Sep; ember 16, 1980
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