ML20207A356

Outlines Three Key Variables of Steam Explosion Issues at Most Probable Values.Optimistic Views Expressed in Current Draft NUREG-1150 Cannot Be Sustained on Basis of NRR Latest Results

ML20207A356
Person / Time
Issue date:	09/09/1986
From:	Kelber C NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
To:	Ross D NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
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References
FOIA-86-678, RTR-NUREG-1150 NUDOCS 8611100230
Download: ML20207A356 (1)

Text

,_____ _ _

?'t UNITED STATES y

NUCLEAR REGULATORY COMMISSION

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WASHINGTON, D. C. 20555 SEP 9 1986 M.EM0rn:DUM FOR: Denwood F. Ross, Jr., Acting Director Office of Nuclear Regulatory Research i

FROM:

Charles Kelber l

Office of Nuclear Regulatory Research l

SUBJECT:

EFFECT OF CANCELLING STEAM EXPLOSION RESEARCH Although I share the general pessimism about getting resolution of steam explosion issues if the attack continues along current lines, I want to make clear that the latest results from NRR's technical assistance program do not lead to a feeling the problem is readily neglected.

The recent work by SAIC and Theophanus leads to the following estimates of the three key variables at their trost probable values:

2 lower grid failure areas: 0.9 n melt energy 1.2 GJ/t conversion ratio 15%

These values lead to an explosien energy of 5.3 GJ, more than enough to rupture any reactor containment.

n If one uses the TMI-2 result that the molten fuel apparently poured through the holes in the grid plate, then one would get significantly more me.s

" premixed" to yield an explosion energy of 20 GJ or so.

Thus, I believe that the optimistic view expressed in the current draft of NUREG-1150 can not be sustained, on the basis of NRR's latest results.

Nevertheless, I have yet to see a program that is based on " analysis before test" and incorporates a program that appears to have a decent chance to elucidate the problem further.

I believe that, failing work on DCH and FCI, we will have to assume early containment failure.

I arles K 1 er

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Office of Nuclear Regulatory Research cc:

W. Morris

!& REA-84-e78 Ntee J. Telford 8611100230 861030 PDR FOIA CURRAN 86-678 PDR 250

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