05000315/LER-2002-001
| Cook Nuclear Plant Unit 1 | |
| Event date: | 01-25-2002 |
|---|---|
| Report date: | 03-15-2002 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(I)(B) |
| 3152002001R00 - NRC Website | |
2002 � 001 � 00 17. TEXT (If more space is required, use additional copies of NRC Form (366A) Conditions Prior to Event Unit 1 - 100 percent power Unit 2 - MODE 6
Description of Event
On January 31, 2002, as a result of questions from the NRC resident inspection team, it was determined that the surveillance requirements verifying the opening, closing, and frictional torque of the ice condenser lower inlet doors were not met. This is a violation of Unit 1 Technical Specifications 4.6.5.3.1.b.3, 4.6.5.3.1.b.4, and 4.6.5.3.1.b.5. Specifically, the past tests failed to consistently achieve a 40 degree open door position and did not consistently achieve a constant scale position on the door in relationship to the door hinge. The previous test methodology resulted in small angular variations (up to 5 degrees) in the door position for each door. The position of the spring scale when measured from the center of the hinge varied from 27 inches to approximately 24.5 inches. Both of these test variations will affect the torque values derived for each door.
The previous opening torque test method and sequence, failed to provide an accurate measure of opening force/torque. Because the frictional torque is determined by dividing the difference between opening and closing torque by two, the frictional torque data was also not considered to be valid. Although, the previous tests did not adequately evaluate the closing force/torque against the technical specification criteria, and did not provide an accurate measurement of door opening torque and frictional torque, the data from the tests performed can still be used to draw conclusions about the condition of the doors, and their ability to function to mitigate design basis accidents.
ice condenser lower inlet doors inoperable on January 31, 2002 at 1358 hours0.0157 days <br />0.377 hours <br />0.00225 weeks <br />5.16719e-4 months <br />. On January 31, 2002, this condition was determined to be reportable in accordance with 10 CFR 50.73(a)(2)(I)(B).
Cause of Event
The cause of the event has been determined to be inadequate testing methodology and inadequate training (i.e., lack of hands-on training) of testing personnel on the proper performance testing and usage of test equipment.
Analysis of Event
Both the Unit 1 and the Unit 2 ice condenser systems including the lower inlet doors were subjected to similar refurbishment prior to the current operating cycle. During the current operating cycle both the ice condenser and containment systems have been subjected to similar maintenance and operational activities. The lower inlet doors were previously tested using an invalid test methodology. Subsequently, the Unit 2 doors were retested and OPERABILITY of the doors was fully demonstrated. Based upon the corollaries drawn, had the Unit 1 lower inlet doors been tested with a valid test methodology, the results would have demonstrated compliance with the technical specification criteria. As such, the Unit 1 ice condenser lower inlet doors are fully capable of performing their design basis function and should be considered to be operable. This event would not have adversely impacted the plant's ability to mitigate the consequences of an accident and therefore had minimal safety significance.
Cook Nuclear Plant Unit 1 05000-315 17. TEXT (If more space is required, use additional copies of NRC Form (366A)
Corrective Actions
- To address the identified deficiencies a special testing procedure to validate operability of the Unit 2 ice condenser inlet doors was developed and implemented.
- Procedure 12/MHP-4030.010.003, lower inlet door surveillance was subsequently revised and implemented using personnel trained to the revised testing requirements to demonstrate compliance with the technical lower ice condenser inlet doors.
- The submittal and receipt of a Limited License Amendment 265 for Unit 1 ice condenser inlet door testing requirements allows continued operation of Unit 1 until the next refueling outage or plant entry into MODE 5 (of sufficient duration). Testing will be completed as specified in this license amendment in accordance approved plant procedure by qualified testing personnel.
Previous Similar Events
There were 13 LERs included in the D. C. Cook Restart Action Matrix Item # 6 for resolution of ice condenser issues.
However, none of the identified issues involved testing to satisfy the technical specifications associated with frictional torque requirements.