ML20062A698
| ML20062A698 | |
| Person / Time | |
|---|---|
| Site: | 05000605 |
| Issue date: | 10/17/1990 |
| From: | Marriott P GENERAL ELECTRIC CO. |
| To: | Chris Miller NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML19302E334 | List: |
| References | |
| EEN-9062, MFN-131-90, NUDOCS 9010230066 | |
| Download: ML20062A698 (2) | |
Text
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- GE Nuclear Energy ;
Gened llutnc Compn '
175 Cwiner A.snw San kse CA 95I2$.
October 17,1990.
3l
. MFN No.131-90 Docket' No. STN 50-605-EEN-9062 -
i Document Control Desk U.S. Nuclear Regulatory Commission 1l Washington, D.C. 20555 Attention:
- Charles L Miller, Director
-l Standardization and Non Power Reactor Project Directorate j
Subject:
Response to NRC/GE May 1617,1990 Meeting Discussion
(
Topics l
Reference:
1.
Dino C. Scaletti,"Sumrnary of Meeting with General'
.i Electric on ABWR", (May 16-17,1990) June 8,19901 2.
Response to.NRC/GE-May:16-17,1990 Meeting <
Discussion Topics, P.W. Marriott to C.L.' Miller, MFN.
No. 099-90, dated August 9,1990.
4 Enclosed are thirty-four (34) copies of our responses to Discussion Topics 4 andl5(b)(2) of the l
Reference 1 meeting pertaining to the shutdown risk and lower drywell flooder steaming rate." Our '
- i response to other discussion topics were provided with Reference 2.
i 7
~
m Please note that the response to Discussion Topic 4, ABWR Shutdown R'isk (Enclosure 1),-is I
designated as General Electric Company p'roprietary information'and the proprietary affiavit for this material is attached.
It is intended that GE will amend the SSAR, as appropriate, in a future amendmenti 4
Sincerely, d
e P. W. Kiarriott, Manager
'-l
- Regulatory and Analysis Services M/C 382, (408) 925 6948 F. A. Ross (DOE) cc:
D. C. Scaletti :(NRC)
G. Thomas (NRC) t' D. R. Wilkins (GE)
J. F. Quirk (GE)'
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s DISCUSSION TOPICS AND RESPONSES -
NRC/GE May 16-17,1990 Meeting i Discussion Tonic 4 - Shutdown Risk I
GE is convinced that the risk during shutdown condition is low for the BWRs.L They will submit a qualitative discussion supporting their beliefs.
g j
Response to Discussion Tonic 4
.q Response is provided in Enclosure 1.
i
.1 Discussion Tonic 5 - Other PRA Tonics as Annronriate i
(b) Lower Drywell Flooder GE will provide 2) estimated steaming rate when substantial amount.
of core debris is ejected into a pool of water in the lower drywell.-
Resnonse to Discussion Topic 5 - Item (bV2)
{
An analysis was performed to determine steaming which could result from two limiting' conditions:
.q (1) Quenching of a debris bed in the lower drywell was estimated based on an observed peak of 15 times critical heat flux. The debris bed was assumed to cover the entire lower drywell floor area.
(2) Quenching of debris falling through a pool of water estimathd by assuming debris quenched instantaneously as it fellinto the pool.. Data for this analysis was taken from-the ABWR i
steam explosion analysis in Subsection 19.2.3.1 of the ABWR SSAR.= This analysis is conservative since the debris may not quench completely as it falls through the pool due to -
1 either coarse fragmentation limiting conduction through the corium) or because of water.
A starved regions (lack of effecti e heat sink).
i Quenching in the debris bed was found to give the limiting steaming rate, about 650 kgs produced.
The effect of this steaming rate on the containment pressure was considered, again in two limits:
(1) All steam generation flows through the horizontal vents into the suppression pool.'
(2) All of the steam pressurizes the drywell for i second to represent vent clearing.'.
The dynamic load was not found to cause a significant threat to the containment for either case.
'I The dynamic load before vent clearing for the debris bed configuration was found to be 0.2 bar, the limiting case.
Therefore, steam generation loads from corium falling into a pool of water after a severe accident '
are not expected to be a threat to containment.
I 4
1 MIN No.13190 Oct.17.1990
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