B12950, Forwards Addl Info Re 880429 Request Concerning Reduction in Boric Acid Concentration in Boric Acid Storage Tanks & Associated Injection Lines

Forwards Addl Info Re 880429 Request Concerning Reduction in Boric Acid Concentration in Boric Acid Storage Tanks & Associated Injection Lines

ML20196J427
Person / Time
Site:	Millstone
Issue date:	06/24/1988
From:	Mroczka E NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20196J430	List: B12950, Forwards Addl Info Re 880429 Request Concerning Reduction in Boric Acid Concentration in Boric Acid Storage Tanks & Associated Injection Lines ML20196J434
References
B12950, TAC-68212, NUDOCS 8807060387
Download: ML20196J427 (7)

Text

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General Offices e Seiden Street, Berlin, Connecticut 1 $'E E85' N " *" P.O. BOX 270 HARTFORD, CONNECTICUT 06141-0270 L ' J CZZT.",,"" (20 0 665-5000 June 24, 1988 Docket No. 50-336 B12950 Re: 10CFR50.90 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Proposed License Amendment Request Additional Information on Boric Acid Concentration Reduction In a Precipitation.Fee Paid|letter dated April 29, 1988]],II) Northeast Nuclear Energy Company (NNECO) submitted a proposed license amendment request to the NRC Staff that would allow a reduction in the boric acid concentration in the Boric Acid Storage Tanks (BASTS) and associated injection lines. The purpose of this letter is ,

to provide the NRC Staff additional information, as requested by the NRC Project Manager, to aid in the review of the proposed license amendment request.

Attachment 1 provides additional information requested concerning the core reactivity parameters. These three (3) tables provide the Doppler, moderator, and xenon reactivity contributions used in the analysis. Attachment 2 is the report prepared by the NSSS vendor for Hillstone Unit No. 2 and was utilized by NNECO to frame the technical justifications presented in Reference 1. This report is provided as an aid to the NRC Staff since pertinent technical justification regarding our licence amendment request is already contained in Reference (1).

NNEC0 has also evaluated the implementation aspects of the proposed changes and has identified an approach which will allow transition from the existing Technical Specifications to the proposed Technical Specifications.

Prior to the first BAST tank being isolated to begin the concentration reduction process, the other, operable tank will be verified to meet Technical Specification requirements for temperature, volume and concentration per "old" l Fig. 3.1-1. The operable tank's associated gravity feed valve and boric acid (1) E. J. Hroczka letter to U.S. Nuclear Regulatory Commission, "Millstone Nuclear Power Station, Unit No. 2, Proposed Revision to Technical Specifications, Boric Acid Concentration Reduction", dated April 1988. 29, f 00 I 8807060387 880624 3 4

fDR ADOCK 05000336 PDC

' 8 U.S. Nuclear Regulatory Commission l B12950/Page 2 e June 24 1988 l

pump will be verified operable. This status will be maintained until the lowered concentration tank is declared back in service. At this time- the e "new" Technical Specifications become effective. The operators shall maintain .

the lower concentration tank in accordance with the requirements of "new"- Fig.

3.1-1 for volume and concentration, considering this tank as the only tank in service for requirements of BAST volume. The reduced concentration tank's associated gravity feed valve and boric ' acid pump must be verified operable.

Following this verification, the other tank can be removed from service and its concentration reduced.

The RWST requirements of volume and concentration for the "new" Technical Specifications will be established and verified prior to the commencement of concentration reduction of the BASTS.

, ' Heat tracing and tank temperatures in any part of the system not specifically meeting the new specifications shall be maintained until the reduction process is completed based upon the last known concentration prior to the commencement of concentration reduction in accordance with "old" Fig. 3.1-1. This will ensure that no boric acid precipitation will occur at any point in the system 3

during the transition.

Prior to the commencement of concentration reduction, all applicable procedures for reduced concentration operation will be revised. These procedure changes will become effective with the commencement of the reduction evolution.

Please contact us if you have any questions.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY E. K fk s Senior)fr6c'zkaVice sident Pre /

cc: W. T. Russell, Region I Administrator D. H. Jaffe, NRC Project Manager, Millstone Unit No. 2 W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos. 1, 2 and 3

Docket No. 50-336 l

B12950 J

Attachment 1 Millstone Nuclear Power Station, Unit No. 2 Additional Information on Boric Acid Concentration Reduction l

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Boric Acid Concentration Reduction Analysis Doppler Temperature Coefficient Temoerature (OF ) Doooler Temoerature Coefficient focm/0F) 532 2.02 500 2.04 450 2.09 400 2.15 350 2.21 300 2.29 250 2.37 L 200 2.47 150 2.57 130 2.62 J

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m Boric Acid Concentration Reduction Analysis Moderator Temperature Deficit Temoerature (OF ) Moderator Temnerature Deficit focm) 532 0 500 1110 450 2500 400 3520 350 4350 300 4950 1

• Temperature below 300 F are extrapolated from these points.

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Boric Acid Concentration' Reduction Analysis Xencn Werth l- Time From Shutdown (hours) Xenon Worth (ocm) 1 0 2809 1 3376 2 3824 3 4170 4 4429 5 4612 6 4732 7 4797 8 4817 9 4799 10 4748 12 4574 14 4330 16 4045

l. 18 3739 l

20 3426 25 2675 30 2027 35 1503 40 1097 45 792 50 566 55 402 60 284 65 199 70 139 75 97 80 03 85 47 90 32 I

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-f Docket No. 50-336 B12950 Attachment 2 Millstone Nuclear Power Station, Unit No. 2 NSSS Vendor Report

-Boric Acid Concentration Reduction l

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