ML19323H783
| ML19323H783 | |
| Person / Time | |
|---|---|
| Issue date: | 05/03/1980 |
| From: | Catton I Advisory Committee on Reactor Safeguards |
| To: | Bates A Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1243, NUDOCS 8006160182 | |
| Download: ML19323H783 (1) | |
Text
I rub HLiEiVED AD'as;;'t r,y.".TiEE OM
()T- /W3 RfACT0c sr.gr;dARDS. II.S N R C. 3 May 1980 MAY 1660 T0:
A. Bates Ap Eas MEMstas O bkl2 l 2 3 4 l
i 1 i i
FROM:
Ivan Catton
SUBJECT:
Coinments on 24 April 1980 Ad Hoc ete Meeting on Natural Circulation -
Natural circulation cooling and under some circumstances reflux cooling of the core are essential to a safe conclusion of a number of transients.
Understanding the phenomena is important if no full scale tests will be run.
g The meeting went a long Way in helping us understand the natural circulation mode of cooling.
Some questions or comments did come up during the meeting that deserve comments.
They are found in the following paragraphs.
1.
Semiscale and LOFT have begun, or are planning, to run transients The planned Sequoyah and North Anna tests that include natural circulation.
combined with the Semiscale and LOFT tests present an unique opportunity for It does not appear as if the NRC research staff has taken code assessment.
as much advantage of this opportunity as they might.
In particular, someone should make sure that the instrumentation at Sequoyah and North Anna are ade-quate for meaningful comparisons to be made with Semiscale and LOFT.
2.
I don't believe o'ne needs to run integral tests to answer questions The about the effect of non-condensible gases on reflux cooling of the core.
new FLECHT program could address this question by perturbing its program plan.
Semiscale plans could be modified to give an early indication of whether or There are probably other facilities available as well.
not a problem exists.
LOFT tests with non-condensibles can then be carried out on an unhurried timetable.
The LOFT small break experiment analysis was not as complete as it 3.
The person making the presentation was not aware of the need might have been.
to have a stratified flow model to account for steam and water counter flow in the horizontal section of the hot 6 g.
His use of homogeneous flow in the horizontal pipe makes his results suspect.
4.
Semiscale can make significant contributions to our understanding of many important phenomena.
I think they should be encouraged to solve the heat loss problem on a priority one basis.
5.
Professor H. Karwat of the Technical University of Munich has hypo-thesized that the first rapid rise in pressure noted during the third hour of the TMI-2 accider.t was due to hydrogen blocking the condensation process in the steam generator. He believes that hydrogen production due to a zirc-steam reaction was unlikely because clad temperatures were not high enough.
His hypothesis about radiolysis leading to large amounts of hydrogen do not seem too credible.
The remainder of his arguments do, however, seem to be important enough to deserve some attention. Where did the hydrogen come from?
6.
Tb"e LOFT instrumentation group seems to be isolated and tends to be unimaginative. A suggestion by Prof. Acosta, bleed water over the window, would allow the Storz lense to be used.
Even without it, 200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> of opera-tion before replacement is not unreasonable when the cost per test is taken i
into consideration.
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