ML19206B214
| ML19206B214 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/15/1978 |
| From: | Tedesco R Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7905080067 | |
| Download: ML19206B214 (4) | |
Text
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DI PT UTION:
KET FILE NO. 50-320 PS READING ASB READING NRR READING RLTEDESCO Occkat No..
50-:2
,O MEFORAitCUM FOR:
D. E. Vassallo, Assistant Director for Light dater Reactors Divisier. cf Project Management FRCll:
R. L. Tedesco, Assistant Director for Plant Systems Division of Systens Safety
SUBJECT:
RESOLUTICli 0F TiG TECH!iICAL SPECIFICATION CnANGES INVCLVING (1) MAXIt'UM ULTIt' ATE HEAT SitiK TEMPEPATUrsE Al;D (2) ?'AI!i STER! SAFETY RELIEF VAL 7ES FLA!iT IEE:
Three Mile Island :iuclear Station, Unit No. 2 CCCXET fiUM5ER:
50-320 LICENSING STAGE:
OL RESPO!iSISLE BRA?iCH:
LUR i;o. 4 PROJECT MANAGER:
H. Silver REQUESTED COMPLETION DATE:
August 14, 1978 REVIEW STATUS:
Complete Enclosed areocur evaluations for two orocosed Technical Specification cnanges in the areas for which we are responsible. The Technical Sceci-fication change involves (1) the nati, mum ultimate neat sink te' perature and (2) the replacement of main steam relief valves for the Three Mile Island nuclear Station, Unit Ho. 2.
We find tne apolicant's crocosal for raising tng technical specifications for tne heat sink maximun temrera-ture to 95 F acceptable. 'We also find accectable tne applicant's preocsn replacecent of tne Main Steam Relief Valves.
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- Dbert L. Tedesco, Assistant Director
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for Plant Systets Division of Systems Safet/) @/.LL *
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e THREE MILE ISLAND NUCLEAR STATION, UNIT NO. 2 C0CKET NO. 50-320 SAFETY EVALUATION OF TECHNICAL SPECIFICATION CHANGE TO APPENDIX A FOR THREE MILE ISLAND NUCLEAR STATION, UNIT 2 1.
INCREASE IN ULTIMATE HEAT SINK TEMPERATURE By letter dated June 5,1978, Metropolitan Edison Company reques :ed a change to the Technical Specifications to raise the Ultimate Heat U
U Sink water temperature frcm the present limit of 85 F to 95 F, Licensee Position The TMI-2 Technical Specifications currently require shutdown of the unit within 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> if the heat sink water temperatare exceeds 85 F.
During the months o' July and August, past operating experience has shown that the temperature of the ultimate heat sink water may ex-U ceed 85 F.
The only case where safety related components perfontance would be degraded due to high heat sink temperatures are components in the control building air conditioning system, whose performance was determined to be not acceptable if the heat sink temperature exceeded 90 F.
The control building booster pumps for this system will be modified to incFease the cooling water flow by 20 percent.
The increase in cooling water flow will pennit the control building air conditioning components to function without degradation in perfo rmance for heat sink temperatures as high as 95 F.
The applicant further proposes to allcw continued coeration of TMI-2 0
for heat sink temperature less than or equal to 90 F until the modi-fications to the control building bocster pumps are complete.
After 94
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modifying the control building bcoster pumps, the operation of TM-2 would be permitted whenever the heat sink temperature is less than.or ' equal to 95 F.
Evaluation and Conclusions Based on our evaluation of the information provided by tha appli-cant and the operating experience of plants similar to TMI-2, we conclude that the operation of TMI-2 when the heat sink temperature 0
is up to 90 F is acceptable. We have also verified that increasing the booster pump flowrate by 20 percent will remove sufficient heat from the control building air conditioning compcnents to enable these components to properly perfom their safety function when the ultimate heat sink temperature is 95 F.
Based on manufacturer's design tempera-tures for safe shutdown equipment cooled by the ultimate heat sink, we conclude that after the modification of the control building booster pumps to increase the cooling water flow is complete, the operation U
of TMI-2 with the heat sink temperatures up to 95 F is acceptable.
Based on the above, we ccnclude that the facility operating license can be amended by changing the Technical Specifications as shown in the Technical Specification Change Request No. 011.
II.
MAIN STEAM SAFETY RELIEF VALVES Introducti on By letter dated July 24, 1978, Metropolitan Edison Company (Met Ed) requested a change to the Technical Specifications to permit replace-9<
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ment of the original 12 dual discharge port main steam safety relief valves with 20 scmewhat smaller single discharge port valves.
Licensee Position During a previous test at TMI-2, some of the orignal main steam safety relief valves failed to close at the appropriate pressure after actua-tion.
Efforts to modify the valves to eliminate the problem were un-successful, and the licensee elected to replace the valves.
These Technical Specifications changes are required to reflect this design change.
The new safety relief valves prcvide a relief capacity of 120 percent
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of the total secondary steam flow as compared with 114 percent provided by the o; iginal valves.
The licensee states that all system modifi-cations conform with requirement of criteria previously accepted in the Final Safety Analysis Report (FSAR), and the cooldown rate will not appreciably change.
Evaluation and Conclusions We have evaluated the information provided by the licensee and find that since the cooldown rate will not appreciably change and the relieving capacity of the new main steam safety relief valves exceeds that originally provided, the proposed change is conserva-tive and is, therefore, acceptable.
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