ML19290A500
| ML19290A500 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/10/1974 |
| From: | US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML19290A447 | List: |
| References | |
| NUDOCS 7911070728 | |
| Download: ML19290A500 (2) | |
Text
h UNITED STATES jh ATOMIC ENERGY CCMMISSION dlyLD P
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- 2 SAFFIY EVALUATION EY TFE DIRECTC!' ATE C4 LICENSI,G
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SUPPOJTISG.eli'ai MI
'.0.1 TO LICEASE AO. DFR-50 (Change.No.1 to Appenclx A of Technical Specifications)
METROPOLITAN EDISCN CCf TAhY JERSEY CENih FCER.CD LIGlil 03!PANY PE.%5YLD:;IA nLECIRIC CCMPAhY
'mREE !!ILE ISIXQ \\" CLEAR STATION - UNIT 1 DOC ET No. 50-239 Introduction By letter dated.'tay 6,1974, Metro,olitan Edisen Company requested a change to the Technical Specificat: :ns appended to Facility Operating License No. DPR-50 for the Three Ale Island Nuclear Station - Unit 1.
The proposed change would temporarily pemit plant wamup and low power (less than 5% of rated power) operation while cne of the electric motor-driven emercency feedsater rancs is cut of ccamission. The Technical Specifications, Appendix A, Section 3.4.3, presently require all three of the emergency feedwater pumps to be operable before the plant is heated to more than 250 F.
Discussion The ability of the E.ergency Feedwater System (EFW) to provide cooling water to the steam generators was considered during the safety evaluation of Three Mile Island Unit 1 (T.II-1). To reevaluate with respect to the proposed Technical Specificatien change there are two aspects to censider:
(1) wamup withcut criticality, and (2) criticality and Icw power operaticn.
Warcup without criticality is clearly acceptable. The EFW pumps are specified or required to provide a means of removing decay heat.
If the plant is wamed up by reactor coolant purp heat and has never been critical, there is no fission product decay heat. The hot plant could be a11 cued to stand with no cooling at all withcut any danage to the fuel.
A sudden release of pressure kilile hot would release the stored energy, but again there wculd be no damage to the fuel. Therefore, a modification of the Technical Specification to allow warmup with one of the EFW umus out of commission is acceptable.
1557 20 To cermit criticality and Icw power physics testing may be considered as permitting indefinite operatica at 5'. pcwer.
Limiti ;; the pcwer to 5',
assures a reduction in decay heat to be removed of a factor of twenty.
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s The EPci system in T.\\lI-1 was designed with a primary, 100t, capacity, turbine-driven pt=p (EF-P1) and two backup, 50", capacity, motor-driven pumps (EF-P2A and EF-P2B). For a full pcwer operating histor,7, removal of all decay heat would require both motor-driven pumos to cperate if the turbine-driven ptrp failed. However, a restriction to 5'; power would mean the twenty-fold reduction of decay heat and only one motor-driven ptcp wculd suffice if it can acceptably serve both sides of the system. The EFN systen is shom in Figure 10-2 of the Final Safety Analysis Report. The diagran shcws all three EF/: ptsps feeding a cc=en header. Each steam generator is served from that header; with the manifold valves EF-V2.\\ and EF-V2E both nomally open, either motor-driven EFU ptcp can feed either steam generator. ::creover, electrical pcwer for stnrting the turbine-driven ptcp is dram from both emergency busses so that the failure of either bus would not cause the simultanecus loss of the ene motor-driven pump and the turbine-driven ptcp.
In view of the above, the EFW systen can provide adequate cooling for decny heat removal with one of the motor-driven pteps not available if reactor power is not allowed to exceed 50"; of rated pcwer. Therefore the temporary change to Technical Specifications proposed by the applicant does not involve a significant hazards consideratica and would not cause undue risk to the health and safety of Fe public.
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Robert M. Eernero, Project ?hnager Light Water Reactors Br. 2-3
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A. Schwencer, Chief Light Kater Reactors Br. 2-3 Directorate of Licensing 1557 321