ML19220B322
| ML19220B322 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/30/1976 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Deyoung R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904250635 | |
| Download: ML19220B322 (3) | |
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Dis tribution:
6 et File NRR Rdg. File RSB File JAN 3 0 576 D. Ross Docket No. 50-3::0 Richard C. DeYoung, Assistant Director for L'a%s, DPM UNRESOLVED SF.R ISSUES REIX"IVE TO TEREE MILE ISLAND, UNIT 2 The requirenents listed in the acciosure are included as open itens in the current draf t of the SIR for Three Mile Island 2.
Satisfactory resolution is considered necessary to nake the safety of this plant consistent with other P*='Rs currently being licensed.
The applicant has been aware of these requirenents through neetings and telephone conversations at the staff has worked to resolve open itens through Q-la and Q-2s.
It i.* recor=aended that the applicant be invited to discuss these issues with the staff at the earliest possible date.
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_ _, 7 D. F. Ross, Assistant Director for Reactor Safety Division of Systa=s Safety
Enclosure:
Unresolved Issues ec:
S. Eanauer R. Beinenan R. Tedesco J. Glynn K. Kniel H. Silver T. Novak R. 3aer W. Finners J. Watt y
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ENCLOSURE THREE MILE ISLAND UNIT 2 1.
The applicant is required to revise ! e cross connect between the two low pressure injection trains into a configuration consistent with plants now being licensed. Manual opening of a valve or valves in the event of need for train interconnection is not acceptable.
Requirements for revision had been identified in Question 21.36.
B&W plants with an acceptable ecnfiguration were listed.
The applicant =ay propose syste=s other than the passive system referenced.
The applicant is to include a discussion cf the design basis of the revised system and an evaluatica of the operation of the system including the case of loss of power to the train not containing the injection line break.
2.
The design and function of the ibin Steam Isolation valves =ust be clarified and resolved. According to the FSAR description of these valves, they have no functiva curing accidents. They are sanually actuated a.d require two minutes to close. This conflicts with an analysis of a feeduater line rupture (S-3-21.49i wherein the valves are required to close in 23 seconds to isolate the steas ger.erators.
The applicant must perform break analysis (feedwater and steam line) without dependence on closure of the turbine stop valves.
If this analysis does not demonstrate adequate core cooling or indi-cates excessive containment pressure, the applicaat mus: make the syste: changes. required to achieve adequate cargins relative to core and containment limits.
3.
Ecrated water supply tank low level and low low level alarns were noted in the Question 22.5 respouse. They are to initiate or re-initiate ope ator action following a LCCA to realign from the injection to the recirculatien codes.
The amount of water remaining in the 3WST is not identified for either alara.
The staff can not now determine if there is sufficient time after the low level alars to reasonably expect the op-ator :: make the switchover from injection to recirculation to avoid c'avitation (f ailure) of the various pumps.
This transition is essential to maintaining core cooling. However, the time at which this action cust be taken is a function of the break sice and during the period followin; a LCCA, there are canv alares competing for the operator's attention.
Concidering this, the staff believes that an adequate time should be allowed for the operator to start to respend to the low level alarm.
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The applicant is required to identify EWST level alar s and use-ful quantities of water associated with them.
Assu=ing the largest break and an adequate ti=e before response, he =ust de=onstrate that there is sufficient time for the switchover to be accomplished.
Include actuatica and valve closure times in a sequential description of this event.
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