A05395, Submits Addl Info Re Anchorage of Condensate Storage Tank & Firewater Tank,Per NRC 851125 SER for NUREG-0824, Integrated Plant Safety Assessment Rept..., Sections 4.4 & 4.7.Anchor Bolts Can Resist High Winds & Tornados

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Submits Addl Info Re Anchorage of Condensate Storage Tank & Firewater Tank,Per NRC 851125 SER for NUREG-0824, Integrated Plant Safety Assessment Rept..., Sections 4.4 & 4.7.Anchor Bolts Can Resist High Winds & Tornados
ML20153C250
Person / Time
Site: Millstone Dominion icon.png
Issue date: 02/04/1986
From: Willie Lee, Opeka J
NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To: Charemagne Grimes
Office of Nuclear Reactor Regulation
References
RTR-NUREG-0824, RTR-NUREG-824 A05395, A5395, NUDOCS 8602190091
Download: ML20153C250 (2)


Text

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.,,s N UTSUTIES f*4 Coper *CteCUTLeGod AfuD.Ceta Conrasse o.n ,.i 0,,,c.. . seio n sire.i. o.,iin. conn.ciicut l "'*'**'""'" C'**** P.O. BOX 270 HARTFORD. CONMCTICUT 06141-0270 k k J ",,0 ,(([,C,"Co.,~, (203) 665-5000 February 4,1986 Docket No. 50-245 A05395 Of fice of Nuclear Reactor Regulation Attn: Mr. Christopher I. Grimes, Director Integrated Safety Assessment Project Directorate Division of PWR Licensing - B U.S. Nuclear Regulatory Commission Washington, D.C. 20555

References:

(1) C. I. Grimes letter to 3. F. Opeka, dated November 25,1985.

(2) Integrated Plant Safety Assessment Report, Millstone Nuclear Power Station, Unit No. 1, NUREG-0824, dated February,1983.

(3) W. G. Counsil letter to D. M. Crutchfield, dated February 2,1984.

Gentlemen:

Millstone Nuclear Power Station, Unit No.1 ISAP Topic 1.19, Integrated Structural Analysis In Reference (1), the Staff issued a Safety Evaluation Report for Sections 4.4 and 4.7 of the Millstone Unit No. 1 Integrated Plant Safety Assessment Report (IPSAR), Reference (2). This SER concluded that Northeast Nuclear Energy Company's (NNECO's) proposal to provide a connection to the city water system and make-up pump for the isolation condenser provides reasonable assurance that in the event of damage to safety related equipment due to high winds and/or tornado missiles, hot shutdown can be achieved and maintained until arrangements can be made to achieve cold shutdown. In this SER, the Staf f also concluded that these modifications, combined with the present capacity of structures and components are sufficient such that no further modifications are warran ted. However, Reference (1) also noted that these conclusions are dependent on confirmation of the capacity of the anchor bolts on the condensate storage tank (CST) and firewater tanks to ensure that they provide substantial resistance against wind-induced failure. NNECO has evaluated the tank anchorages, and is providing the following information.

The firewater tank is anchored by twelve 1 1/2 inch diameter anchor bolts while the condensate storage tank is held by sixty 1 1/2 inch diameter anchor bolts equally spaced around the circumference of the tanks as shown on NUSCO drawings 25202-11013 and 11014. Copies of these drawings have been provided to the Millstone Unit No.1 ISAP Project Manager. The anchor bolts for the CST 86021o 391 860204

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are Williams grouted rock bolts, type "C," long cone and shell with short flange, and 2'-10" in length. The anchor bolts for the firewater tank are 4'-0" long, 11/2" diameter thread rods with an anchor plate encased into the concrete foundation of the tank. The details of embedment for each of the tanks are such that the embedment capacities of the bolts far exceed the tensile capacity of the anchor bolts. The anchor bolts are placed through anchor bolt chairs which are fully welded to each tank and then encased by 5,000 psi concrete. The anchor bolt chairs for the tanks have been analyzed and have sufficient structural capacity to transfer ^ e anchorage force from the chair to the tank.

As stated in Reference (3), a detailed analysis was performed to determine structural capacity of the tank and anchor bolts during a tornado wind condition of 300 mph. The calculation showed the anchor bolt loads and details to be below allowables for the postulated tornado wind loading. The structural analysis performed on the tanks and on the anchorage systems for the firewater tanks and condensate storage tank showed that the tanks and the anchor bolts are capable of withstanding a 300 mph tornado wind speed. Therefore, it has been demonstrated that the anchor bolts for the CST and firewater tanks are able to provide substantial resistance against high winds and tornados, thereby providing two sources of makeup water to the isolation condenser.

Based on the above, NNECO considers this issue to.be satisfactorily resolved. If you have any questions on this, please con tact us.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY f

M 322/Opeka V Senior Vice President 4

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By: W. F. Fee Executive Vice President t

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