05000302/LER-2003-004
| Crystal River Unit 3 | |
| Event date: | |
|---|---|
| Report date: | |
| 3022003004R00 - NRC Website | |
On October 17, 2003, Progress Energy Florida, Inc., (PEE) Crystal River Unit 3 (CR-3) was in NO MODE (Reactor Vessel Defueled) at zero percent RATED THERMAL POWER. While implementing Engineering Change (EC) 51164, 'Upgrade the Keyboard Commander; it was necessary to de-energize Safety Parameter Display System (SPDS) [IP] equipment. When performing steps to de-energize this equipment, CR-3 personnel noticed that the SPDS power supplies [IP, JX) to the display servers [IP, MON] and peripherals in the Main Control Room were reversed.
The SPDS equipment plugs Into standard 120 volt alternating current receptacles [ED, RCP).
Power strips are used for this application. Drawing 210-254, Sheet 3, depicts Train A SPDS equipment as being plugged into power strip "BN." Train B SPDS equipment Is depicted as being plugged into power strip "BP." Power strip "BN" is depicted as being plugged into receptacle "BS.
Power strip "BP" is depicted as being plugged Into receptacle "BR." The as-found configuration had SPDS Train A equipment (power strip "BN") plugged into SPDS Train B receptacle "BR" and SPDS Train B equipment (power strip "BP") plugged into SPDS Train A receptacle "BS.
Improved Technical Specification (ITS) 3.3.17, Post Accident Monitoring (PAM) Instrumentation [IP], requires that PAM instrumentation for each Function in Table 3.3.17-1 shall be OPERABLE in MODES 1, 2 and 3. Table 3.3.17-1, Line Item 21, requires two channels of Degrees of Subcooling [IP, CHA]. ITS 3.3.17, Condition C, states that with one or more Functions with two required channels inoperable, restore one channel to OPERABLE status within seven days.
Degrees of Subcooling (Subcooling Margin) is displayed in degrees Fahrenheit on both SPDS displays. The SPDS is the primary display of margin to saturation for each Reactor Coolant System (RCS) [AC) loop. This variable is used by the operator to trip the Reactor Coolant Pumps (RCPs) [AC, P) within two minutes of the loss of Subcooling Margin. In the as-found configuration, the loss of one Vital Bus Distribution Panel (either VBDP-3 or VBDP-4) [EF, PL] would cause the loss of one SPDS monitor. By having the SPDS power supplies reversed, the SPDS computer and Hub that feeds the available SPDS monitor would also be lost. In effect, two channels of the Degrees of Subcooling Function were not operable.
The identified condition is considered to have existed for a period of time longer than allowed by ITS 3.3.17. Therefore, the condition is being reported under 10CFR50.73(a)(2)(1)(B) as a condition prohibited by Technical Specifications.
SAFETY CONSEQUENCES
The purpose of the SPDS is to assist the control room operator in the evaluation of plant conditions during both normal and abnormal situations. The system is designed to use a minimum number of displays and parameters, yet it concisely presents to the operator information concerning the safety status of the following functions required by NUREG-0737, Revision 1, and NUREG-0696: reactivity control; reactor core cooling and primary system heat removal; RCS integrity; radioactivity control; and, containment integrity. The SPDS can be used to quickly focus on abnormal areas, thus limiting the number of control room indicators to be reviewed for further monitoring.
The SPDS is the primary display of margin to saturation for each RCS loop. This variable is used by the operator to trip the RCPs within two minutes of the loss of Subcooling Margin. However, Administrative Instruction Al-505, "Conduct of Operations During Abnormal and Emergency Events," Step 4.2.9.3, states that if SPDS is unavailable, subcooling margin is determined by plotting RCS temperature and pressure on Enclosure 5 or 6 of this procedure or on the same figures of applicable Emergency Operating Procedures (EOPs). EOP-03, "Inadequate Subcooling Margin," Step 2.1, states that if RCPs were not stopped within two minutes, then ensure one RCP remains running in each RCS loop to avoid core damage. This procedural guidance provides sufficient backup during a loss of SPDS to allow operators to perform required actions within specified time frames.
Based on the above discussion, PEF concludes that the identified condition did not represent a reduction in the public health and safety. This event does not meet the definition of a Safety System Functional Failure.
CAUSE
The cause for incorrectly labeling the SPDS power strips was inadequate work instructions in Modification Approval Record (MAR) 96-11-03-01 which was implemented in October 1999. The instructions were not written where the worker could have followed them and been assured that power strip labeling was accurate per plant drawings. The Administrative Controls in place at the time (Nuclear Engineering Procedures) were much less specific than current process controls (EGR-NGGC-0005, Engineering Change). For this reason, no corrective actions are necessary to address this cause.
A contributing cause was insufficient post modification testing. Following the work performed under MAR 96-11-03-01, the post modification testing verified power supplies to the BS and BR receptacles from VBDP-3 and VBDP-4 breakers, but did not include testing to verify that the SPDS equipment and peripherals were plugged into the correct receptacles per plant drawings. Due to the nature of this equipment and its requirements to be powered by independent power supplies, the post modification testing should have included this level of detail.
CORRECTIVE ACTIONS
1. The SPDS power strips have been properly labeled.
2. No corrective actions are required to address the historical condition of inadequate labeling. Current engineering change procedures are considered adequate to ensure proper labeling during the implementation of engineering changes.
3. � Other actions associated with this event (e.g., the contributing cause) are being addressed in the CR-3 Corrective Action Program In Nuclear Condition Report 108023.
PREVIOUS SIMILAR EVENTS
No previous similar events associated with SPDS power supplies to the display servers and peripherals in the Main Control Room being reversed have been reported to the NRC by CR-3.
ATTACHMENTS
Attachment 1 - Abbreviations, Definitions, and Acronyms Attachment 2 - List of Commitments notify the Supervisor, Licensing & Regulatory Programs of any questions regarding this document or any associated regulatory commitments.
RESPONSE
SECTION
COMMITMENT DUE DATE
No regulatory commitments are being made in this submittal.