ML19220B019
| ML19220B019 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/17/1978 |
| From: | Vassallo D Office of Nuclear Reactor Regulation |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| NUDOCS 7904250205 | |
| Download: ML19220B019 (1) | |
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SISTRIBUTION:
Ddeket file LWR-4 Reading
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D. Vassallo
. u, January 17, 1978 ftEMORANDUit FCR:
K. V. Seyfrit, Assistant Director for Technical Programs, I&E FR0!!:
D. B. Vassallo, Assistant Director for Light Water Reactors, CPM
SUBJECT:
PROBLEM INVOLVING INTERRUPTION OF REACTOR COOLANT PUMP SEAL WATER FLOW UPON LOSS OF OFFSITE POWER This is in response to your meno on the same subject of December 12, 1977, regarding Three Mile Island Unit 2.
Discussions with NRR personnel and the applicant have resulted in the following understanding of the problec and its solution.
The problem which had existed is that in the event of a loss of offsite power and a failure in the single seal water line to the RC pump seals, the =anual precedures necessarf to align an alternative source of water to the seals required about 5-6 minutes. The maximum time for which toe seals can be without water to assure no damage due to overheating and subsequent themal shock when water is reintroduced is 1-4 minutes.
The applicant has documented on page 9.3-21 of the FSAR (Amendment 60),
and will make further clarifying changes in Amendment 62, that a parallel redundant seal water line will be installed. We understand this modification was scheduled to be complete by January 1,1978. This addition precludes single failure interruption of seal water ficw, and limits the time during which the sesis will be without water to that required for the dieseis to pick up the pucps supplying that water, about 23 seconds.
We are further infomed that the loss of power test to be perfomed will include a c:x::plete trip of offsite pcwer, which will simulate this eYent during operation.
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Based'en this infomation, we conclude that this plant modification and -
the proposed test are acceptable.
Original signed by D. B. Yassafjo
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m MEHORANDLH FOR:
K. V. Seyfrit, Assistant Director for Technical Pro
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PROBLEM INVDLVING Ih7ERMJPTION OF REAC'IVR CCOL\\ST PLNP SEAL WATER FLOW UPON LOSS OF OFFSITE POWER
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This is in response ta yetn? neco\\on the same subject of December 12, 1977, regarding Three Mile Island \\ Unit 2.
Discussions with NRR personnel and the applicant have resulted in the following understanding cf the problem and its solution.
'Ihe problem which had existed is thtt in the event of a loss of offsite power and a failt:re 'r. Se ringle seal water line to the RC pu=p seals, the =anual procedures neceey to align an alternative source of water to the seals required about 5-6 tainutes. The m time for which the seals can be without water to assure mo damage due to overheatinst. and subsequent thermal shock hnrvamtiW#Mrbdfe'e@ib'-$fEiriu't'es.-
i The applicant has docune\\nted on page 9.3-21 cf the FSAR (Amendnent 60),
and will make further clarifying changes in h \\t 62, that a parallel redundant seal water line sill be installed. We aderstand this modification is scheduled to be ec=plete bM'ta71,1973. This addition precludes single failure interruption of seal water flow, and limits the time, during which the seals will be without water to that required for the diesels to pick up the pumps supplying that water, about 28 seconds.
We are farther informed that the loss of power test to be perforned will include a coczplete trip of offsite power, which will simulate this event during operation.
Based on this inforz:ation, we believe this plant modification and the proposed test are acceptable.
D. B. Vassallo, Assistant Director 777/{
for Light Water Reactors Division of Project Management cc:
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