ML20039F738

Responds to Generic Ltr 81-21, Natural Circulation Cooldown. Procedures for Cooldown Will Incorporate Natural Circulation Test Program & Guidance Provided in Abnormal Transient Operating Guidelines Program

ML20039F738
Person / Time
Site:	Midland
Issue date:	01/08/1982
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Harold Denton Office of Nuclear Reactor Regulation
References
14912, GL-81-21, NUDOCS 8201130290
Download: ML20039F738 (2)

Text

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Consumets Power James W Cook Vice President - Projects, Engineering ord Construction p 6

General officas: 1945 West Parnali Road, Jackson, MI 49201 e (517) 7880453 b January 8, 1982 C CSpj JQ -

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Harold R Denton, Director N W Office of Nuclear Reactor Regulation Division of Licensing US Nuclear Regulatory Commission Washington, DC 20555 MIDLAND PROJECT MIDLAND DOCKET NOS 50-329, 50-330 RESPONSE TO GENERIC LETTER 81-21 FILE: 0928.6 SERIAL: 14912 NRC Generic Letter No 81-21 dated May 5, 1981 and entitled " Natural Circulation Cooldown" identified two areas of concern applicable to all pressurized water reactors that required action. These areas of concern are (1) the unacceptability of vessel voiding during anticipated cooldown conditions and (2) failure of the operator to have prior knowledge and training for this event. Consumers Power Company was requested by Generic Letter No 81-21 to assess the Midland Plant procedures and training program with respect to the two identified areas of concern. The assessment was to include three items. Consumers Power Company responses to the three identified items for Midland Plant procedures and training program are as follows:

1. Item A demonstration (eg, analysis and/or test) that controlled natural circu-lation cooldown from operating conditions to cold shutdown conditions, conducted in accordance with your procedure, should not result in reactor vessel voiding.

Response

A natural circulation test program will be performed which is consistent with the guidance contained in the NRC letter from R L Tedesco to J W Cook, dated April 22, 1981, and recent natural circulation test programs at NTOL facilities. The test program will include cooldown capability. Strict control of cooldown rate and water subcooling limits should prevent void formation. Results of the testing will be reflected 3 00/

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2. Item Verification that supplies of condensate grade auxiliary feedwater are sufficient to support your cooldown method.

Response

If it is assumed that natural circulation cooldown is conducted without the availability.of the condenser, then energy _is removed from the steam generators by steaming to the atmosphere. Analysis shows that 224,000 gallons of water is needed for one unit assuming steam removal via two of four POAV valves. The proposed Technical Specifications require a minimum of 290,000 gallons of onsite stored water for both units. Cooling pond water can also be utilizied using a service water pump to supply water to the AFW pump suction.

3. Item A description of your training program-and the provisions of your procedures (eg, limited cooldown rate, response to rapid change in presurizer level) that deal with prevention or mitigation of reactor vessel voiding.

Response

The training program for Reactor Operator and Senior Reactor Operator candidates is provided in the Midland FSAR Section 13.2.1. Phase E,

" Nuclear Power Plant Simulator Training" will be modified to include training on localized steam voiding in the reactor coolant system.

Localized steam _ voiding will also be included in Phase F, "On Site Systems Training" and requalification training. Those license candidates having Phase E and Phase F completed will receive localized steam voiding training during requalification training.

Plant procedures for natural circulation cooldown will incorporate the results of 'the natural circulation test program noted in Item 1 above and the guidance provided in the Abnormal Transient Operating Guidelines Program being developed by the NSSS vendor.

/hh G JWC/JRW/fms CC RJCook, Midland Resident Inspector DSHood, US NRC TPSpeis, US NRC DBMiller, Midland Construction (3)

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