ML19323C268
| ML19323C268 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 02/21/1980 |
| From: | Bender M Advisory Committee on Reactor Safeguards |
| To: | Plesset M Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML19323C261 | List: |
| References | |
| ACRS-SM-0182, ACRS-SM-182, NUDOCS 8005150232 | |
| Download: ML19323C268 (2) | |
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NUCLEAR REGULATORY COMMISSION g
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS Ts(,y /1 l masm warow. o.c. mass g
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February 21,1980 FEB2319Pp i
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Dr. Milton S. P1'esset California Institute of Technology l
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Pasadena, CA 91109
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Dear Milt:
Since I probably will not be at the March ACRS meeting, I wanted to offer some coments on the questions which you asked the Bulletins and Orders Task Force to address.
I see nothing wreng with folding the B&O recomendations into 1.
the NRC Action Plan if the Action Plan establishes an order If there is no prder of priority.
of priority for the work.
then we will never be able to tell when the work should be I believe that many of the B&O recomendations are completed.
If prerequisites to plant operation, some having deadlines.
the deadlines are not met, presumably the plants will be shut down. The response from the MET-ED organization to the questions raised concerning the startup of TMI-l was not The ACRS put prime importance on unambiguous reassuring.
indication of coolant level in the reactor vessel and it was not clear that the NRC staff even had an understanding with the TMI organization about this matter. Further, we i
know very little about the training aspects of the B&O effort
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and they may be the most important safety actions.
- Probably, I
we should concentrate our attention on the training area.
am' fairly certain that the mechanical fixes and the electrical l
changes will be sorted out.
I think it should be a requirement that the block valves be 2.
able to close upstream of the PORVs against design flow and Do we understand the basis.on which block valve pressure.
closure capability has been established?
l 3.
I am personally opposed to the " feed and bleed" made of plant cool down when secondary side cooling is lost, if that means l
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Dr. Milton S. Plesset 2
February 21, 1980 1
opening and closing the PORV. We should be able to rely on the high pressure injection system to cool the plant when small trnks occur without PORV operation. The major concern in my mind is whether the system can be filled completely with liquid water without adequate relief capacity. That aspect of safety should be examined carefully.
I believe we should try to take a position wherein the PORVs are not required to be operated rapidly for safety purposes and it would even be permissible to " gag" the valves for operational purposes.
4.
The B&O reconinendations for reducing small-break-type LOCAs is a good short tenn action since it will reduce the frequency of demand on the PORVs.
5.
I am not adequately clear on the safety issue raised by Northeastern Utilities concerning auto initiation of auxilliary feedwater systems. We need a better understanding of the
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potential consequences before taking a position.
6.
I believe we must show that reactor coolant pump trips under i
any circumstance will not interfere with natural circulation cooling in PWRs.
If there are current difficulties arising from such action, then engineering correction is needed.
Automatic tripping of reactor coolant pumps should be acceptable under reactivity shutdown conditions. We should look more carefully at this transient, but my intuitive 1
judgment is that the circumstances where trouble could arise involve extremely rare events that ought to be ruled out on a probability basis.
Sincerely, m
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l M. Bender MB/mh cc: Paul Boehnert R.F.Fraley/
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