ML20127E722

SER Supporting Util 840629 Response to Generic Ltr 84-09, Recombiner Capability Requirements of 10CFR50.44(c)(3)(ii)

ML20127E722
Person / Time
Site:	FitzPatrick
Issue date:	06/17/1985
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20127E700	List: ML20127E696 ML20127E722
References
GL-84-09, GL-84-9, NUDOCS 8506240631
Download: ML20127E722 (4)

Text

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SAFETYEVALUATIONBYTHEOFFICEOFNUCLEARREACTORREbO[ATION JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333 RECOMBINER CAPABILITY REQUIREMENTS OF 10 CFR 50.44(c)(3)(ii) (RESPONSE TO GENERIC LETiER N0. 84-09)

Background

- ~ Oh~ December 271981, the NRC amended 10 CFR 50.44 of its regulations by 4 addition of the provisions in 10 CFR 50.44(c)(3). One of these provisions -

requires licensees of LWRs, that rely upon purge /repressurization systems'as the primary means of hydrogen control, to provide a recombiner capability by 7 - the end of the first scheduled outage after July 5,1982, of cufficient t duration to permit the required modifications. Those plants for which notices of hearing on applications for construction permits were published on or after November 5, 1970, are not permitted by 10 CFR 50.44(e) to rely on purge /repressurization systems as the primary means for hydrogen control.

Therefore, these plants are not affected by the requirement for recombiner capability. However, the FitzPatrick plant is affected by the new requirement.

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As a result of the new inerting requirements in 10 CFR 50.44(c)(3), the I. BWR Mark I Owners Group undertook a substantial program to demonstrate that the Mark I plants potentially affected by the recombiner capability requirements of the rule do not need to rely on the safety grade purge /

h repressurization system required by the original 10 CFR 50.44 rule as the primary means of hydrogen control. Extensive review and independent studie

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by the NRC staff supported the findings of the Mark I Owners Group program._s -

The' Commission has determined that a Mark I BWR plant will be found to not rely on purge /repressurization systems as the primary means of hydrogen control, if certain technical criteria are satisfied. These criteria were provided in the Generic Letter No. 84-09 (Ref. 1), dated May 8, 1984, which was sent to all licensees of operating reactors. Therefore, the recombiner capability defined in 10 CFR 50.44(c)(3)(ii) need not be furnished for those inerted Mark I BWR containments where the licensees are able to demonstrate that the Generic Study (Ref. 2) is applicable to the licensee's. plant and that the following three criteria are met: (1) the plant has Technical Specifications requiring that, when the containment is required.to be inerted, the containment atmosphere be less than four percent otygen; (2) the plant has only nitrogen or recycled containment atmos all pneumatic control systems within containment; and (3)phere there arefor no use in i

potential sources of oxygen in containment other than that resulting from radiolysis of the reactor coolant.

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Most of the affected Mark I BWR plants have Containment Atmosphere Dilution (CAD) Systems utilizing either nitrogen or air. In order to clarify 'the staff's position regarding these systems, Generic Letter 84-09 Stated that a plant that has a " safety grade" purge /repressurization system de' signed to conform with the general requirements of Criteria 41, 42 and 43 of Appendix A of 10 CFR Part 50 and installed in accordance with 10 CFR 50.44(f) or 10 CFR 50.44(g) must continue to have that system, even though it may be determined with respect to 10 CFR 50.44(c)(3) that the plant does not rely l on that system as the primary means for hydrogen control; thus, a decision '

on recombiner capability does not affect the requirements of 10 CFR 50.44(f) and 10 CFR 50.44(g) for the " safety grade" purge /repressurization system.

Evaluation

~ ~ IT a letter da'ted June 29,1984, (Ref. 3), the licensee for James A.

% FitzPatrick Nuclear Power Plant, the Power Authority of the State of New -

York, submitted a response to the staff's Generic Letter 84-09. The licensee stated that the criteria presented in Generic Letter 84-09 are

- satisfied for the FitzPatrick facility, and therefore, a recombiner y capability is not required.

The NRC staff has reviewed the compliance of FitzPatrick with the criteria presented in Generic Letter 84-09. We have found that the license.a has participated in the generic study (Ref. 2) made by the BWR Owners Group.

The main parameter regarding the applicability of the study was found to be the ratio of the core themal power to the free drywell volume. The

,g applicability of the study to FitzPatrick was addressed in Chapter 1.3 of p the study.

We agree that the conclusions of the generic study are applicable to FitzPatrick, and that the above-referenced three criteria of Generic b Letter 84-09 are satisfied as follows:

,- (1) FitzPatrick Technical Specification 3.7.A.6 requires that when the -

containment is inerted, the containment atmosphere is to include less than four percent oxygen by weight (which corresponds to approximately 3.5 percent by volume). This figure is more conservative than the staff's requirement of less than 4 percent by volume.

This satisfies the first of the three criteria of Generic Letter 84-09.

(2) The pneumatic systems located within the drywell at FitzPatrick have the capability of using either nitrogen or air. Nitrogen 4s nomally used when the containment is inerted. The Instrument Air System can be used as a back-up to the nitrogen supply. Previous' operating procedures did not ensure that only nitrogen would be used*in the pneumatic control systems located within containment. Thellicensee, however, has revised the operating procedures by requiring that isolation valves on lines connecting the back-up air system to the

drywell be locked shut to prevent an inadvertent inleakage of air during power operation.

Therefore, we find that FitzPatrick meets the second of the three criteria of Generic Letter 84-09.

(3) The licensee performed an engineering study to identify potential sources of oxygen within the containment. Oxygen sources such as the Service Air and Breathing Air Systems are normally disconnected from the drywell piping during power operation. However, previous operating procedures did not require the isolation valves on lines connecting these systems to the drywell to be locked shut. The licensee has revised these procedures by requiring the locking of these valves.

The accumulators in the Automatic Depressurization System (ADS) were evaluated by the staff as a possible oxygen source. These accumulators, located within the drywell, are initially filled with nitrogen. Howver, during cold shutdown, the accumulators, could par. sally fill with air from the Instrument Air System upon a loss of line pressure. Later activation of the ADS could then result in air being ejected into the containment. Calculations indicate, however, that the amount of air from this source would be negligible. In addition, control room personnel would be alerted to the loss of line pressure and appropriate action would be taken prior to startup. The only credible source of oxygen was found to be from radiolysis of reactor coolant.

Therefore, we find that FitzPatrick satisfies the third of the three criteria of Generic Letter 84-09.

Conclusion We conclude that a recombiner capability for the James A. FitzPatrick Nuclear Power Plant is not required since the criteria defined in Generic Letter 84-09 have been satisfied.

Principal Contributor: P. Salminen Dated: June 17,1985 6

References:

(1) LetterfromD.G.EisenhuttoAllLicenseesdatedMay8,'1J84, "Recombiner Capabilit Requirements of 10 CFR 50.44 (c)(3)t.fi)"

(Generic Letter 84-09 .

1 (2) " Generation and Mitigation of Combustible Gas Mixtures in Inerted BWR Mark I Containments," by F. R. Hayes, L. B. Nesbitt and P. P.

Stancavage. Technical Report NED0-22155/82-NE00-69/ CLASS 1/ June 1982.

(3) letter from J. P. Bayne, NYPA, to D. R. Vassallo, NRC, dated June 29, 1984, "Recombiner Capability Requirements of 10 CFR 50.44 (c)(3)(ii)."

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