ML20086T969

Summarizes 950707 Conference Call Re Subject RAI

ML20086T969
Person / Time
Site:	05200004
Issue date:	07/17/1995
From:	Green T GENERAL ELECTRIC CO.
To:	Robert Elliott NRC
References
OG95-457-161, NUDOCS 9508030217
Download: ML20086T969 (2)

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• GENuclear Energy .

Ger.eraillectnc Cornpany b OG95-457-161 115 Cwtner Awwe. San hw CA 95125 1 July 17,1995 )

Rob Elliott (8H7)

US Nuclear Regulatory Commission One White Flint North -

11555 Rockville Pike 1 Rockville, MD 20852-2738 I l

SUBJECT:

CLOSURE OF BWR OWNERS' GROUP RESPONSE TO NRC " REQUEST

' FOR ADDITIONAL INFORMATION REGARDING THE STRAINER TEST l PROGRAM BEING CONDUCTED BY THE BWROG" ,

i This letter summarizes the July 7th conference call regarding the subject RAI dated June 22,1995.

in accordance with our discussion on July 10th the BWROG will not formally respond to this RAI but will include all requested information in the final BWROG test report.

As discussed on July 7th:

1. The 20 point star strainer can be considered to be full scale for most BWRs. The 5000 gpm .

flow is on the high side of the typical ECCS pump flows, and at many plants the maximum required flow is less than 2500 gpm. At a few plants the required flow is significantly higher than 5000 gpm. The strainer size will likely be limited by loads issues not the required flow rate.  ;

2. The water volume in the EPRI test loop piping system is less than 800 gallons. This volume is ,

insignificant with respect to the 50,000 gallon test tank. ,

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3. The debris concentration samples obtained during the earlier phase 1 testing were not analyzed due to plateout in the sample bottles. Samples obtained in July confirm homogeneous mixing at 5000 gpm flow rates. The BWROG has observed that at 2500 gpm flow rates some settling will occur.

4. As-built sketches of the test facility will be included in the final test report.

5. The experimental test results will be integrated into the Utility Resolution Guidance  !

documentation. Because steady state head losses are determined following multiple strainer filter bed recycles, experimental test results are considered to be conservative. These head loss results will be used to specify the operability range for each strainer tested, and we will i incorporate results into the STRAIN code for plant unique transient analysis.

6.' The head loss in run 13 is higher than run 15 using the same materials because:

i the filter bed was formed at 5000 gpm where no settling occurs, and the bed was  !

compressed at a dp of 220" of water for run 15 some material inherently settled out as the flow never exceeded 2500 -

gpm, maximum head loss was approximately 40" of water g(

.A 950so30217 950717 PDR ADOCK.05200004 PDR p .hf 0

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4 se OG95-457-161 July 17,1995 Page 2 We do not understand the NRC statement that head loss increased when the flow was decreased.

In run #13 the head loss exceeded 220" of water at 5000 gpm versus 160" of water at 2500 gpm.

Actual head loss in run 15 was approximately 40" of water.

7. We have provided the NRC a copy of the preliminary test matrices for the additional passive strainer testing and self-cleaning strainer testing. This shows the method that the BWROG will employ to add material step-wise and then to later verify that the incremental results are the same when all the debris is added at the same time. This method was confirmed to be acceptable in the earlier phase 1 testing.

If you have any questions regarding the BWR Owners' Group ECCS Suction Strainer Committee ,

activities, please call the undersigned or the Committee Chairman, (R. Rocky) Sgarro at (610) 774-7552.

Very truly yours, 1

TA Green Senior Technical Project Manager BWR Owners' Group Projects Tel: (408)925-1308 Fax: (408) 925-2476 Mail Code 182 TAGTz J cc: RA Pinelli, BWROG Chairman KP Donovan, BWROG Vice Chairman ECCS Suction Strainer Committee SJ Stark, GE l

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