ML20149J578
| ML20149J578 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 06/23/1995 |
| From: | Berlinger C NRC (Affiliation Not Assigned) |
| To: | Ader C NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| Shared Package | |
| ML20149E342 | List: |
| References | |
| FOIA-97-129 NUDOCS 9507030289 | |
| Download: ML20149J578 (2) | |
Text
h
'.,8'q}'
- UNITED STATES
+ny,
i
,A NUCLEAR REGULATORY COMMISSION
-('gi
]c :
wAssencios. o.c. 2 oms-oooi
,'%g
}-
- .~
~ June-23, 1995 MEMORANDUM T0: ' Charles Ader, Chief; Accident Evaluation Branch
- Division of. Systems: Technology I
- FRON:i Carl Berlinger, Chief Containment Systems and Severe Accident Branch gj{
Division of Systems Safety and-Analysis y
SUBJECT:
APPLICATION OF PASSIVE AUT0 CATALYTIC RECOMBINERS TO AP600 Westinghouse has verbally notified the staff that, as part of the design certification of the AP600, they intend to use Passive Autocatalytic i
Recombiners (PARS) for the control of combustible gases following a design basis loss-of-coolant -accident.. The staff's review criteria are outlined in Section 6.2.5, " Combustible Gas Control In Containment," of the Standard Review Plan-(SRP).
We had expected to receive a formal submittal from Westinghouse by the end of May 1995.
As of this date we have_still not received the submittal.
Section 6.2.5 of the SRP bases acceptance of the functional capability of the PARS on confirmatory analyses"using' the COGAP computer model.. Presently, the COGAP computer code is unable.to model hydrogen depletion by a-PAR. We are requesting technical assistance from your branch to modify this computer model and perform the confimatory calculations as required by Section 6.2.5 of the SRP.
The only performance data the Containment Systems and Severe Accident Branch (SCSB) is aware of.for developing such a computer model was submitted by EPRI in a report titled, " Qualification of. Passive Autocatalytic Recombiners For Passive Autocatalytic Recombiners In ALWR Containments," dated April 8,1993.
In a letter dated March 10, 1994 your branch provided us comments on this.
submittal. We believe that it would ba in the staff's best interest to perform confirmatory experiments to verify PAR performance data and to address i:
the concerns raised by your response.
We would need the resul,ts from these
[
cxperiments by December 1995.
' Another area where we require technical assistance from your branch is in i
determining the affect of diffusion flames on the containment shell.
Using the Hydrogen Control-Owners Group data as a guide, the anticipated hydrogen combustion. behavior in the in-containment retueling water storage tank (IRWST) wculd be diffusion flames anchored on the surface of the pool.
If there is insufficient inflow'of oxygen into the IRWST, diffusion flames may anchor on the IRWST vents.
SCS8 is' interested in a determination of the thermal loads i
resulting from.these flames on the containment shell.
CONTACT: Mike Snodderly, NRR/SCS8 415-2047 fikmcy QA]g&
- f,.j, l
Passive DBA Hydrogen Control p/
G issue:
-l o Westinghouse using 2 full size passive autocatalytic recombiners (PARS) for design basis accidents i
o PARS have never been used in a licensed design for DBA hydrogen control i
o Analyses must be provided to show that hydrogen combustion is prevented by ensuring that the hydrogen concentration in tl'e containment never reaches 4 percent, its lower flammability limit i
i t
4 4
l l
.