ML20204G835

Forwards Util 860716 Record of Coordination Clarifying Standby Liquid Control Sys Min Sodium Pentaborate Solution Concentration Specified in Util

ML20204G835
Person / Time
Site:	Clinton
Issue date:	07/27/1986
From:	Siegel B Office of Nuclear Reactor Regulation
To:	Butler W Office of Nuclear Reactor Regulation
References
NUDOCS 8608070399
Download: ML20204G835 (2)

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JUL 2 71986 Docket No. 50 *S1 MEMORANDUM FOR: Walter R. Butler, Director BWR Project Directorate No. 4 Division of BWR Licensing FROM: Byron L. Siegel, Project Manager BWR Project Directorate No. 4 Division of BWR Licensing

SUBJECT:

STANDBY LIQUID CONTROL SYSTEM (SLCS) MINIMUM S0DIUM PENTABORATE SOLUTION CONCENTRATION In a May 23, 1986 letter Illinois Power Company (IP) specified a 10.2 weight percent concentration of sodium pentaborate to compensate for a lower nominal flow rate of 41.2 gpm which is being used to account for normal degradation over the life of the SLCS pumps. Since this weight percent concentration and flow rate was not proportionately consistent with those previously specified IP was requested to provide a clarification which is contained in the enclosed Record of Coordination from IP dated July 16, 1986.

OdginalsWed W Byron L. Siegel, Project Manager BWR Project Directorate No. 4 Division of BWR Licensing

Enclosure:

As stated DISTRIBUTION (Docket File NRC PDR LPDR PD#4 Rdg.

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1. 7/&//86 8600070399 860727 PDR ADOCK 05000461 A PDR

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• Y-202780 Prepared by: T. L. Riley, V-920 9.1 Date _ July 16. 1986

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Copies to: i.A.Spangenberg,VI File Code L30-86(07-16)-L J. D. Weaver, V-920 Retention Code L S. W. Plummer, V-920 Record Type 1A.165 P. J. Telthorst, (N&H) V-920 Class of Record 0 W. F. Bradley, V-920 Quality of Record NS Licensing Files: CLIP OMC #14 RECORD OF COORDINATION Type: Meeting X Telecon Other:

Date: July 15, 1986 Time: 2:00 p.m.

Participants:

T. L. Riley, (IP) and B. L. Siegel, (NRC)

Subject:

Standby Licuid Control System (SLCS) Minimum Sodium Pentaborate Solution Concentration Summary Mr. Siegel called to question the basis for the minimum solution concentration j specified in IP Letter U-600582 dated May 23, 1986.

The ATWS Ru.le 10CFR50.62 specifies that an equivalent boron content and flow capacity of 13 weight percent at 86 gpm be obtained. A minimum 10.0 weight percent sodium pentaborate concentration was specified in IP Letter U-600279 dated October 16, 1985 to satisfy the 13 weight percent equivalent requirement for a 218 inch diameter reactor vessel. The 10.0 weight percent was based on a nominal 43 spm flow rate for each SLCS pump.

In the IP letter dated May 23, 1986, a 10.2 weight percent concentration was specified because a lower nominal flow rate of 41.2 gpm is used to account for normal degradation over the life of the SLCS pumps.

Mr. Siegel questioned why the required concentration did not increase on a direct retio of flow from the 10.0% originally specified. I explained that the 10.0%

was determined by rounding off a lower figure (9.8) to be an even number at 10.0.

Therefore, a direct ratio applied to 10.0% should not be used and the 10.2%

specified in the recent IP letter is the correct result of the GE calculation for solution concentration.

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