ML19345D773
| ML19345D773 | |
| Person / Time | |
|---|---|
| Issue date: | 02/13/1980 |
| From: | Ebersole J Advisory Committee on Reactor Safeguards |
| To: | Etherington H Advisory Committee on Reactor Safeguards |
| Shared Package | |
| ML19345D770 | List: |
| References | |
| ACRS-M-0022, ACRS-M-22, NUDOCS 8012160608 | |
| Download: ML19345D773 (1) | |
Text
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- f r.
_a TG:
H. Itheringto.)
FRON:
J. Ebersole f
SUBJECT:
Some observations on information presented 1.
There seem to be no criteria for upgrading the secondary system to reduce " sensitivity" to transients.
There is a vague goal of reducing void formation without a definition of what progressive void formation does in a damaging sense up to uncovering the core or reducing the margin to cover.
be difficulty in restoring natural convection.It has been-implied that there may I believe that the investigations are proceeding normally in that criteria are now, but not earlier, in order. One has to understand the system to develop reasonable criteria.
2.
There was no discussion of the caliber or " safety grade" of the re-actor coolant pump. trips.
Normally these pumps are provided with non-safety grade breakers, power supply and trip circuits. To up-grade same is moderately expensive. A resolution is needed.
3.
It was not clear that adequate reliability is provided in assuring main feedwater trip.
The mechanical reliability of the level modulating valves to close is unproven against the forward differential pressure associated with a steam line break.
The main steam line closure is safety grade, thus o.k.
The main FW turbine trip is not safety grade except in a limited sense.
Normally these are not seismic - nor in a seisedcally qualifief, structure.
The DC trip supplies may not be qualified.
In short, considering the potential for primary containment failure -
as well as overcooling - I don't yet see adequate proof of main feed-water trip.
4.
Re " bleed and feed *, if it works in all aspects, it would seem that natural convection, as well as upgrading secondary systems, would be less important than otherwise.
discussion of bleed and feed beyond that in Pebble Springs questions.Ho Until such adequacy of this mode is well substantiated (by more infor-mation then so far presented) we must presume that secondary cooling function is critical to safety.
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