United States Nuclear Regulatory Commission - Protecting People and the Environment

LICENSEE: STONE AND WEBSTER ENGINEERING CORPORATION

SITE: NINE MILE POINT UNIT TWO EN NUMBER:36708
DOCKET: EVENT DATE: 12/17/1999
RX TYPE: EVENT TIME: 12:00[EST]
VENDORS: NOTIFY DATE: 02/18/2000
EMERGENCY CLASS: REGION: 1 STATE: NY TIME: 14:24[EST]

HQ OPS OFFICER: DOUG WEAVER

10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH

Part 21 - Non-Conservatism in Environmental Qualification (EQ) Calculations

1-. Affected unit: Nine Mile Point Unit 2

2- Components that contain defect/deviation: Miscellaneous components (limitorque operators electrical cables etc.) in environmental qualification (EQ) program

3- Firm supplying components/activity: Stone and Webster Engineering Corporation (SWEC)

4- Nature of defect/deviation: non-conservatism in EQ calculations (lowest expected ambient temperatures used instead of normal expected ambient temperatures for winter periods). About 30 components will have qualified lives reduced from greater than 40 years to less than 40 years, when non-conservatism is removed. Several hundred other components will have qualified lives reduced but not to less than 40 years.

5- Date on which information was obtained (discovery date): December 17. 1999

6- Number and location of components: potentially numerous components in multiple systems at multiple locations.

7- Corrective actions: EQ calculations and Environmental Qualification Engineering Design Criteria document, which was source of erroneous data for the EQ calculations, will be corrected prior to expiration of actual qualified lives of affected EQ components i.e., within a few years.

Page Last Reviewed/Updated Thursday, March 29, 2012