2CAN088914, Requests Waiver from 30-minute Time Requirement of NUREG-0737,Item II.F.1.6, Hydrogen Monitoring Capabilities. Waiver Requested to Cover Time Remaining Until Upcoming Refueling Outage to Begin on 890925

Requests Waiver from 30-minute Time Requirement of NUREG-0737,Item II.F.1.6, Hydrogen Monitoring Capabilities. Waiver Requested to Cover Time Remaining Until Upcoming Refueling Outage to Begin on 890925

ML20246P184
Person / Time
Site:	Arkansas Nuclear
Issue date:	08/25/1989
From:	Turk C ARKANSAS POWER & LIGHT CO.
To:	Poslusny C NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.1, TASK-TM 2CAN088914, 2CAN88914, NUDOCS 8909110066
Download: ML20246P184 (3)

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Ark:nsas Pow 2r & Light Comp:ny ye @ 425 West Capitol P O Box 551 Lit'ie Hock. AR 7P203 '

Tel 50137/ 4000 '

I August 25, 1989 2CAN088914 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station F1-137 Washington, DC 20555 ATTN: Mr. Chet Poslusny, NRR Project Manager

~NRR Mail Stop 13-D-18

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Hydrogen Monitoring Capabilities -

Request for Waiver of Compliance Gentlemen:

In the course of evaluating an internally identified design deficiency, AP&L has determined that specific features of the ANO-2 Hydrogen Sampling System are not in full compliance with provisions of NUREG 0737, Item II.F.1.6.

Specifically, the guidance requires that hydrogen monitoring be functioning within 30 minutes of the onset of safety injection. Contrary to this requirement, AP&L procedures provide that hydrogen monitoring be initiated within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The details surrounding this deficiency were discovered as e -result of our investigations in response to the previously mentioned design deficiency, and were discussed in teleconferences with NRR and Region IV staffs on August 24.

The purpose of this letter is to document our responses to the concerns and to formally request a waiver from the 30 minute time requirement of NUREG 0737 Item II.F.1.6. The waiver is specifically requested to cover the~ time remining until the upcoming ANO-2 refueling outage, scheduled to begin September 25. Additional design evaluations are being conducted to identify the optimum long term solution to the design deficiency and the feasibility of complying with the 30 minute criterion. If any further deviations from these requirements appear necessary, detailed justifications will be submitted for cpproval as soon as possible end prior to startup for the next operating cycle.

Oh 8909110066 890E25 JV

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PDR ADOCK 05000368 0 P -PUC L

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2CAN088914 Page 2 August 25, 1989 ,

J The previously mentioned design deficiency pertains to failure to meet the single failure criterion for the ANO-2 Hydrogen Analyzers. Specifically, AP&L determined that a specific set of assumed events could lead to a loss of immediate monitoring capability. The loss could occur as a result of failure of the " red" power source following successful containment isolation but prior to initiation of monitoring. Since both Hydrogen Analyzer Return Line Isolation Valves (inside containment) are powered from the same (red) channel, this failure could preclude hydrogen monitoring.

Although the item was considered reportable per 10CFR50.72 (i.e., outside the design basis of the plant), operability of the analyzers was considered to be maintained for the following reasons. The safety analyses regarding hydrogen generation clearly show that the lower limits are not approached until approximately three days following the accident (assuming conservative hydrogen generation rates based upon 10CFR50.44). Thenfore ample time exists to take actions necessarj to provide an alternate power source to the valve in question. It has beer estimated by AP&L that the alternate power supply arrangements could be made in approximately three hours or less. Furthermore, procedures provide clear instructions that hydrogen removal using the internal recombiners be initiated before 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (irrespective of indicaced hydrogen concentration) in response to a LOCA. The design basis analysis clearly demonstrates the adequacy of a single recombiner to effectively control post LOCA hydrogen concentration under these assumptions (reference AN0-2 SAR section 6.2.5 and figure 6.2-25).

Nonetheless, it is evident that even wi'h special provisions to providt alternate power to the isolation valve, the 30 minute functional criteria of NUREG 0737 Item II.F.1.6 cannot be met. This matter is not considered safety significant for the reasons stated above.

In addition it should be noted that other than placing recombiners in operation, the Hydrogen Analyzers are not considered a critical element of any essential operator actions.

In order to reduce the vulnerability to the postulated single failure concern, the ANO-2 Emergency Operating Procedures are being revised to ensure that Hydrogen Monitoring can be established within approximately three hours. Additionally, specific instructions and tooling have been assembled to accomplish the alternate power transfer mentioned above.

l l As stated before, AP&L will be carefully evaluating the various design and l operational impacts of resolving these issues. We will provide the results l

o 2CAN088914 Page 3 August 25, 1989 of our evaluations and any additional information for your review and approval as may be required.

Ve y truly yours, Charles H. Turk Acting Manager, Licensing CHT:fc l

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