05000249/LER-2002-001
| Dresden Nuclear Power Station Unit 3 | |
| Event date: | 03-23-2002 |
|---|---|
| Report date: | 05-22-2002 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2492002001R00 - NRC Website | |
A. Plant Conditions Prior to Event:
Unit: 03 � Event Date: 03-23-2002 Reactor Mode: 2 � Mode Name: Startup Reactor Coolant System Pressure: 150 psig
B. Description of Event:
Event Time: 1603 CST Power Level: 002 percent This event is being reported in accordance with 10 CFR 50.73 (a)(2)(i)(B), which requires reporting "any operation or condition which was prohibited by the plant's Technical Specifications.
On March 15, 2002, Unit 3 was shut down to replace seventeen jet pump hold down beams. During the maintenance outage, extensive work was performed on the High Pressure Coolant Injection (HPCI) [BJ] system.
The post maintenance tests (PMT) required a low pressure HPCI surveillance to verify no leaks at system pressure.
On March 23, 2002, Unit 3 commenced a normal unit startup per station procedures. Prior to reactor pressure reaching 150 psig, the Unit Supervisor (US) declared the HPCI system inoperable and questioned whether the HPCI isolation valves, 3-2301-4 and 3-2301-5, were required to be open. This was questioned because the HPCI low-pressure test was scheduled to be performed at 165 psig with 2 turbine bypass valves open. The HPCI system was believed to be inoperable by the US due to the maintenance work performed during the outage.
Technical Specification (TS) 3.5.1 "ECCS-Operating", requires HPCI to be operable in Modes 1, 2 and 3 when reactor steam dome pressure is >1= 150 psig. The US determined that the valves could remain closed. This was based on an incorrect assumption that the system was inoperable until the low-pressure test was completed. The US requested a peer check of his determination. The Operations Outage Manager, Shift Outage Manager and the augmented Senior Reactor Operator performed that peer check. Following the discussion, the 3-2301-4 and 3- 2301-5 valves were left in the closed position until the unit had reached the test conditions.
Subsequently, the Shift Operations Superintendent (SOS) arrived while the HPCI low-pressure test was in progress. The SOS reviewed the unit logs and recognized the HPCI system was not aligned to a standby condition prior to the unit reaching 150 psig. The SOS directed the US to amend the log entry that HPCI was inoperable until it was successfully aligned and tested.
However, on March 25, 2002, a review by site Regulatory Assurance personnel concluded that TS 3.5.1 requires HPCI to be operable in Modes 1, 2 and 3 when reactor steam dome pressure is >1= 150 psig and the plant had operated in a condition that was prohibited by the plant's TS. The Operations decision to consider HPCI inoperable and raise pressure was an incorrect application of the Technical Specifications for this condition. The correct application for this situation is to assume operability after the maintenance work was performed, not enter any LCOs, and to validate that assumption by testing when suitable conditions exist.
C. Cause of Event:
The root cause of this event was a knowledge deficiency associated with HPCI applicability which was complicated by the historical aspects of a TS note and the understanding of intent. The individuals involved focused on the Surveillance Requirements and not the applicability section of the TS. When questioned why the FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) Dresden Nuclear Power Station Unit 3 05000249 (If more space is required, use additional copies of NRC Form 366A)(17) focus was on the surveillance, both assumed HPCI operability would be proven during the testing.
(NRC Cause Code E) To understand how Dresden licensed individuals acquired this mindset, a review of past outages, previous TS questions, correspondence regarding plant commitments, and limiting condition of operation (LCO) practices was conducted. During previous outages (D2R14 and D3R14), DNPS performed a unit start up with HPCI uncoupled.
When the unit reached 150 psig, a 12-hour LCO time clock was entered for testing. Once all testing was complete and HPCI re-coupled, unit start-up progressed. This investigation found a plant commitment letter and an operations policy question discussing this situation. Both state that the footnotes in previous TS 4.0.D allowed the site to extend the applicability for the required function. This guidance was inappropriate and fostered the current mindset. A review of all technical specification LCO applicability sections was performed to determine if similar issues existed for other TS sections. Based on this review, there are appropriate procedures and programs in place to prevent a similar event.
D. Safety Analysis:
The safety significance of this event is minimal. The plant was in startup at low reactor pressure (150-psig) during the period when the HPCI steam supply valves were closed. The Automatic Depressurization System, Isolation Condenser, Core Spray systems, and Low Pressure Coolant Injection system were operable and capable of performing their intended safety function.
E. Corrective Actions:
Provide Operator training on this event and applicable sections of Technical Specifications regarding section 3.0 compliance.
Personnel involved were coached and counseled as to the requirements and interface with Limiting Conditions of Operation in Technical Specification section 3.0.
Reviewed all Technical Specifications Limiting Condition of Operation Applicability sections to identify any sections that could cause a similar event.
Historical operations policy questions will be reviewed to determine if additional training is required to ensure TS compliance.
F. Previous Occurrences:
A search of previous history found that Dresden had started the unit up with the HPCI turbine uncoupled from the pump during D2R14 and D3R14. This would render the HPCI system inoperable and it is similar in that for both events, HPCI was inoperable during a change of condition.
G. Component Failure Data:
N/A