Alert

Due to a lapse in appropriations, the NRC has ceased normal operations. However, excepted and exempted activities necessary to maintain critical health and safety functions—as well as essential progress on designated critical activities, including those specified in Executive Order 14300—will continue, consistent with the OMB-Approved NRC Lapse Plan.

Part 21 Report - 1999-070

LICENSEE:	ABB COMBUSTION ENGINEERING
SITE:	ABB COMBUSTION ENGINEERING	EN NUMBER:	35271
DOCKET:		EVENT DATE:	01-15-99
RX TYPE:		EVENT TIME:	14:15
VENDORS:		NOTIFY DATE:	01-15-99
EMERGENCY CLASS:	N/A REGION: 1	STATE: CT	TIME: 14:15
OPS OFFICER:	DOUG WEAVER
10 CFR SECTION:	CCCC UNSPECIFIED PARAGRAPH

PART 21 NOTIFICATION RELATED TO MINIMUM CRITICAL POWER RATIO(MCPR)

"The purpose of this letter is to notify the Nuclear Regulatory Commission of a defect under 10 CFR 21, 'Reporting of Defects and Noncompliance.' The defect concerns the Operating Limit for the Minimum Critical Power Ratio (MCPR) in Boiling Water Reactors(BWRs) analyzed using the BISON fast transient analysis code. Specifically, the defect involves incorrect modeling of the reactor vessel lower plenum volume in the BISON code, which could lead to the establishment of non-conservative MCPR Operating Limits in plant technical specifications.

"The Enclosure summarizes the evaluation performed by ABB Combustion Engineering (ABB-CE). If you have any questions, please feel free to contact me [Ian C. Rickard] or Virgil Paggen of my staff."

This event effects WNP-2 current operating cycle (Cycle 14).

Page Last Reviewed/Updated Wednesday, March 24, 2021