This 24-hour report is being made as required by Braidwood Unit 1 License Condition 2.G as a potential violation of the maximum power level 3586.6 MWt as stated in Unit 1 License Condition 2.C(1).
Braidwood is conservatively reporting an overpower condition on Unit 1 due to the implementation of an ultrasonic flow measurement system. Unit 1 was potentially overpowered a maximum of 1.07%. This value is based upon the maximum ultrasonic flow meter correction factor used for Unit 1 during the period between June 1999 and September 2003.
During post installation testing of the permanent ultrasonic flow measurement system, discrepancies in the ultrasonic flow measurement system were identified that could have resulted in an overpower condition of Unit 2 during the previous use of the ultrasonic system (i.e., during the period between June 1999 and September 2003). The ultrasonic flow measurement system was used to correct venturi feedwater flow measurements. The corrected feedwater flow measurements were then used is the calorimetric calculation for reactor power.
Currently Braidwood Unit 1 and Unit 2 are controlling power level based only on the venturi feedwater flow indication.
The licensee notified the NRC Resident Inspector.
