ML20128E016

Advises of Recent Info Obtained from Exam of Irradiated 7x7 Fuel Assemblies Presently Stored at Plant Spent Fuel Pool

ML20128E016
Person / Time
Site:	Monticello
Issue date:	07/01/1975
From:	Buckley B Office of Nuclear Reactor Regulation
To:	Ziemann D Office of Nuclear Reactor Regulation
References
NUDOCS 9212070449
Download: ML20128E016 (2)

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DISTRIBUITON D ocket s ORB #2 Reading RMDiggs FLASil NOTE o l

Dennis L. Ziemann, Chief, Operating Reactors Branch #2, RL

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>DNTICELID NUCLEAR GENERATING PIANT FUEL CLADDING FAILURE 7

j PURPOSE To adviss Management of recent information obtained from examination of irradiated 7 x 7 fuel assemblies presently stored in the Monticello facility spent fuel pool. The Monticello Nuclear Generating Facility is owned and operated by the Northern States Power Cotpany (NSP).

1 OIRONOLOGY

! 1. On June 30, 1975, the Office of Inspection and Enforcement Headquarters personnel alerted us of a recent examination of Monticello irradiated 7 x 7 fuel assemblies which revefied significant failure of the fuel cladding.

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2. Upon receipt of the above information, I cs11ed Mr. Ned Choules (Region 111) and he gave no the following information:

a. Ten traadiated 7 x 7 fuel assenblies, three of which were removed in March 1974 and the remaining seven in January 1975, were examined by use of a television camera,

b. 1he examination revealed 30 of the 40 corner fuel pins had cracks ranging from 1" to 3' in length. Some crack propagations were of l spiral configuration with one fuel pin having a l"s wide crack. Fuel i i pins other than the corner pins had only minor defects.

3. I discussed the above matter with Technical Review personnel and a meeting is scheduled for 1:00 p.m. July I with the Core Performance Branch to further discuss this topic. The principal concern is whether a generic proble.n may exist since the fuel pin failure was primarfly confined to the corner fuel pins. (There are 266 7 x 7 fuel assemblies of identical desiLn presently installed in the Honticello core which are scheduled to be replaced by 8 x 8 fuel assemblies in October 1975.)

FutIN -UP ACTION A conference call has been scheduled for 2:30 p.m. July 1 to discuss this matter further with NSP. Wo members from the Core Performance Dranch will visit the Monticello facility to examine the irradiated fuel and participate in further discussions, d( appropriate. Management will be kept advised of any significant developnents on this subject. g g

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