ML032650715

Part 21 Report Regarding an Apparent Abnormality Involving Boral Spent Fuel Pool Test Coupons

ML032650715
Person / Time
Site:	Seabrook
Issue date:	09/16/2003
From:	North Atlantic Energy Service Corp
To:	Laura R, Peschel J NRC Region 1
References
Download: ML032650715 (2)

Text

0//0 09116Q2003 U.S. NuclearRegulatory Commission Operations Center Event Report Page1 Power Reactor Event# 40159 Site: SEABROOK Notification Date I Time: 09/1512003 16:40 (EDT)

Unit: I Region: I State: NH Event Date Time: 09/15/2003 (EDT)

Reactor Type: [1] W-4-LP Last Modification: 09/15/2003 Containment Type: DRY AMB NRC Notified by: JAMES PESCHEL Notlficatlons: CORNELIUS HOLDEN NRR HQ Ops Officer: RICH LAURA HAROLD GRAY RI Emergency Class: NON EMERGENCY JACK FOSTER NRR 10 CFR Section:

21.21 UNSPECIFIED PARAGRAPH Unit Scram Code TRX Crit Init Power Initial RX Mode = - _ Curr Power Current RX Mode 1 N lYes 100 Power Operation l100 Power Operation PART 21 ISSUE AT SEABROOK ON SPENT FUEL POOL TEST COUPONS The licensee reported an apparent abnormality involving Boral spent fuel pool test coupons. Westinghouse built the spent fuel pool racks using Boral material manufactured by ARR Inc. Specifically, Inspection of test coupons revealed bulging or blistering of the aluminum cladding. The Information provided by the licensee does not include any other affected plants.

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_+ 5--23 17:134 NFESCO LICENSING 603 773 7740 P.02/02 Licensee FPLE Seabrook Site Seabrook Station  : Xt V Docket 50-443 I (

Reactor Type Westinghouse PWR Date September 15, 2003 10CFR 21 Notification FPLE Seabrook has identified an apparent abnormality of a Boral coupon that was removed from the Spent Fuel Pool for inspection. Boral test coupons (Boron carbide &

Aluminum Composite Material) have been located in the Spent Fuel Pool as monitoring specimens to assess the performance of similar Boral neutron poison material incorporated into the spent fuel pool racks. Westinghouse Electric Corporation built the spent fuel pool racks using Boral material manufactured by ARR Inc. of Livomia, MI.

Visual inspection of one Boral Coupon indicated bulging of the Boral aluminum cladding that nomially encapsulates, and is adhered to, the internal Boron carbide & Aluminum Composite layer. The structural integrity of the clad material has been affected but there as been no evidence of loss or redistribution of the boron carbide in the active poison layer of the Boral Material at this time. A number of bulges were observed on the periphery of the coupon. The inspection yielded no apparent loss of neutron absorbing material. Two additional coupons w ere inspected. The inspection of these coupons resulted in similar bulges being observed.

All sixteen irradiated Boral coupons were inspected and characterized after all coupons had been removed from their stainless steel jackets. These inspections indicated a range in coupon condition from blisters approximately equivalent to those previously inspected too slightly blistered and one coupon with no outward indication of blisters.

The boron-10 areal density in the Boral has been measured via neutron attenuation testing. This testing determined that areal density was within specification and no loss of control material existed. Furthermore, the impact of the blistering on the flux trap has been determine to be small and within bounds of the criticality analysis. Thus, the Boral is presently performing its design fimction.

However, the rate of blister formation and the long-term effects of these blisters on the criticality analysis is not known. Analysis performed to date suggests that this blistering will continue. Thus over a period of time, this condition could worsen which may result in operation of the spent fuel pool outside the bounds of the criticality analysis. FPLE Seabrook considers the above condition to be reportable pursuant to 10 CFR 21.21.

Because of the uncertainty in the fture state of the Boral, Seabrook is planning to implement a Boral Monitoring program and to add a blistering allowance in the Spent Fuel Pool criticality curves.

The six Boral racks constitute 576 of the 1236 storage cells in spent fuel pool. All the spent fuel storage racks are freestanding self-supporting modules.

TOTAL P.02 09/15/2003 MON 16:32 [TX/RX NO 86161 Qj002