05000316/LER-2002-001
| Donald C. Cook Nuclear Plant Unit 2 | |
| Event date: | 01-26-2002 |
|---|---|
| Report date: | 03-28-2002 |
| 3162002001R00 - NRC Website | |
2002 01 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 26, 2002, during reactor core offload for refueling outage 13, 10 CFR 50 Appendix J, Type B and C leak rate testing was being performed in accordance with procedure 02-EHP-4030-234-203, "Unit 2 B & C Leak Rate." Step 53 of the procedure provided valve lineup instructions for Type C leak rate testing of the nitrogen to pressurizer relief tank check valve 2-N-159. The auxiliary equipment operator (AEO) who preformed the valve lineup for testing signed off the procedure step indicating that the root shutoff valve 2-GPX-301-V1 from the nitrogen supply manifold was "closed" as required by procedure. Upon successful completion of the test, the procedure requires a valve restoration lineup. The test was not impacted by the mispositioned valve. A different AEO who performed the restoration for the valve lineup noticed that valve 2-GPX-301-V1 was in the "open" position, thereby creating a potential direct access from the containment atmosphere to the outside atmosphere. Upon discovery, the control room was notified and core alteration was suspended A post event investigation of this incident revealed that the AEO who performed the initial valve line up for testing observed that valve 2-GPX-301-V1 was tagged "Do Not Operate Without SRO CA Permission" as required by procedure 02-OHP- 4030-STP-041 for refueling integrity purposes. This AEO had been involved with previous testing that required the lifting of STP-041 tags. On January 26, 2002, the AEO performed the lineup which required valve 2-GPX-301-V1 to remain closed.
He had a mind set from the previous day's activities that he needed to remove the STP 41 tag and open the valve. The AEO inappropriately removed the tag and opened the valve without verifying the required position of the valve for testing.
Technical Specification (TS) requirement 3.9.4.c requires that each containment penetration providing direct access from the containment atmosphere to the outside atmosphere be either closed by an isolation valve, blind flange, manual valve, or equivalent. The failure to verify valve 2-GPX-301-V1 closed during core alteration resulted in a breach of refueling containment integrity. This breach of refueling integrity is prohibited by TS and is therefore reportable in accordance with 50.73(a)(2)(i)(B).
Cause of Event
The cause of this event was failure to follow procedures. The AEO who performed the lineup for B & C leak rate testing opened valve 2-GPX-301-VI and inappropriately pulled the "Do Not Operate" tag from the valve contrary to the requirements of plant procedures 02-EHP-4030-234-203 and 02-0HP-4030.STP.041.
Analysis of Event
The Bases for TS 3.9.4.c states that the requirements on containment building penetration closure and operability ensure that a release of radioactive material within the containment will be restricted from leakage to the environment. The operability and closure restrictions are sufficient to restrict radioactive material release from a fuel element rupture based upon the lack of containment pressurization potential while in refueling mode.
Based on investigation of this incident the valve was mispositioned for approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />. There was no impact on the health and safety of the public as a result of this event.
Corrective Actions
Upon discovery Operations restored valve 2-GPX-301-V1 to the closed position thereby re-establishing refueling integrity.
A review of the completed B & C testing lineups impacting refueling integrity was conducted and verified that no other loss of containment integrity had occurred during previous refueling operations.
2002 01 00 17. TEXT af more space is required, use additional copies of NRC Form (366A) The human performance and personnel accountability aspect of this issue have been appropriately addressed.
A lessons learned memo was published and distributed to the auxiliary equipment operators.
Previous Similar Events
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