L-90-301, Discusses Generic Implications & Resolution of Control Element Assemblies Failure at Plant

Discusses Generic Implications & Resolution of Control Element Assemblies Failure at Plant

ML20059B289
Person / Time
Site:	Saint Lucie
Issue date:	08/16/1990
From:	Sager D FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-90-301, NUDOCS 9008280359
Download: ML20059B289 (3)

Text

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,_K P.O. Box 14000, Juno Beach,FL 334000420 0 AUG 161990 EE L-90-301 1

U. S. Nuclear Regulatory Commission _

~ Attn: Document Control. Desk- I Washington, DC 20555 l Gentlemen:

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Re

.St.- Lucie Unit 1 Docket 50-335 Generic Implications and Resolution of-CEA Failure at Maine Yankso P

By-~ letter dated July 6, 1990, the Nuclear Regulatory Commission '(NRC) staff _ requested additional information from Florida Power and Light (FPL)- 1 regarding the Combustion Engineering Regulatory Response Group (CERRG) ,

Action Program for addressing the issue of irradiation assisted stress '

corrosion cracking (IASCC) in Control Element Assemblies (CEAs). . Thet staff also requested that FPL confirm its intention to implement- the -

referenced Action Program for St. Lucie Unit ~1 and - provide the final' results of eddy current test (ECT) inspections of the old-style CEAs discharged to the St. Lucie Unit 1 Spent Fuel Pool.

By L-90-272, dated July 17, 1990, FPL confirmed its intent to follow the CERRG Action Program as well as committing to provide the~results of the '

completed ECT. inspection. FPL also committed to utilize the data taken:

during the ECT to update the CERRG Action Program.

FPL exercised the 17 old design CEAs having high exposure histories in the Unit 1 core after the recent reactor coolant pump outage in accordance; with item 3 of the CERRG Action Program. Attachment One to this letter provides the requested summary of the results of the ECT inspection of the old design CEAs in the St. Lucie Unit 1 Spent Fuel Pool. Attachment Two provides the updated Action Program which=FPL intends to follow for the remainder of Unit 1, cycle 10 operation.

Should you have any questions, please contact us.

Very,truly yours, '

hah /

D. A ager

'Vice esident.

St. cio Plant ,

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, L .L b3 DAS:JMP:kw Attachments (2) cc: Stewart D. Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant

.DAS/PSL #234 9008280359 900816 b an FPL Group company PDR ADOCK 05000335 p\

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,,m Attachment One FLORIDA POWER AND LIGilT ST. LUCIE UNIT 1 EDDY CURRENT TEST INSPECTION RESULTS Florida Power and Light (FPL) has conducted an eddy current test (ECT) inspection of the old style CEAs which have been discharged to the Unit 1 Spent Fuel Pool. Old style CEAs were defined as those lacking a Ag-in-Cd slug in the center finger, in accordance with FPL's July 17, 1990 response to the staff's Request for Additional Information, dated July 6,1990.

FPL identified 54 CEAs in the Unit 1 Spent Fuel Pool which met the revised criterion. Four of these CEAs were excluded from the ECI' inspection program because the center fingers of the assemblies contained aluminum slugs, and did not have any B4 C pellets within the center finger tip. Therefore, a total of fifty CEAs were considered for testing and inspection. As stated in the referenced correspondence, an initial sample of 25 CEAs was considered for testing. This sample i was expanded to all 50 old CEAs as a conservative measure.  !

l The visual inspection verified the structural integrity of all end caps: no anomalies were detected.'  !

No circumferential cracking was identified. The eddy current inspection identified five axial crack-  !

like indications in the lower portion of the center fingers of five CEAs with exposure histories ranging from approximately 3800 to 4300 effective full power days (EFPD). Four of these 1 indications were less than 1/4" in length while the fifth was 3.4" long. No other crack-like ,

indications were iden:ified.

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- Attachment Two I; ..

FLORIDA POWER AND LIGIIT ST LUCIE UNIT 1 REVISED CEA ACTION PROGRAh!

. Eddy current testing, as described in the FPL response to the July 6,1990 NRC Request for -

Additional Information, has been conducted and completed.

. Based upon the results of the eddy current testing, Florida Power and Light (FPL) intends to

- operate for the remainder of Cycle 10 with the existing CEAs in the core. The additional actions listed below will be perfomied to ensure the integrity of the 17 high exposure, old design CEAs in the Cycle.10 core for the remainder of the cycle: q

. A full insenion/ withdrawal exercise of the 17 high exposure old design CEAs will be  !

perfomied after each cold shutdown and reactor trip. l

• The structuralintegrity of the 17 high exposure old design CEAs will be verified on a .I quarterly basis. Several methods to perfomi on-line testing are being evaluated. l

. If exercising (or other CEA movements) shows evidence of a stuck CEA, the unit will be shut down and the old style CEAs will be inspected or replaced.* 3 i

. All old design CEAs will be replaced with new CEAs during the Cycle 10 refueling outage. -j

• Not required if stuck CEA attributed to cause not associated with loss of CEA integrity (nonnal procedure would be followed). 1 I

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