05000285/LER-2012-005
| Fort Calhoun Station | |
| Event date: | 02-21-2012 |
|---|---|
| Report date: | 06-01-2012 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2852012005R01 - NRC Website | |
BACKGROUND
The Emergency Diesel Generators (EDGs) fuel oil transfer pumps are skid mounted electric pumps located next to each of the EDGs. There are two pumps for each EDG. Each EDG has a suction pipe from the diesel generator fuel oil storage tank (FO-1). The fuel oil transfer pumps for each EDG draw fuel from the suction pipe for the respective EDG. Each EDG has a wall mounted fuel oil day tank that is supplied by the fuel transfer pumps. The day tanks have level indication on the outside of the tank, a manual drain valve on the bottom of the tank, a vent, and an overflow line that goes back to FO-1.
Each day tank also has four level switches, high and high-high level switches, and low and low-low level switches. The fuel oil transfer pumps have three control switches. Each pump has a three position switch with positions HAND, OFF, and AUTO. There is also a two-position selector switch with positions labeled NO 1 and NO 2.
During normal operation, the control switches for each fuel oil transfer pump are placed in AUTO and the selector switch is placed in the NO 1 position. In this arrangement, when the day tank low level switch actuates, the number 1 fuel oil transfer pump energizes to fill the tank. In the event that the number 1 fuel oil transfer pump fails to operate, the low-low level switch will start the number 2 fuel oil transfer pump. With the selector switch in the NO 2 position, the number 2 fuel oil transfer pump would start on low level and the number 1 pump would start on low-low level.
The original Fort Calhoun Station (FCS) Technical Specifications (TSs) issued May 24, 1973, included a requirement to test the diesel generator fuel oil transfer pumps monthly. Monthly fuel oil transfer pump testing is currently required by TS 3.7(1)e. and Table 3-2, Item 12.
EVENT DESCRIPTION
During a review of surveillance procedures, a failure to perform complete surveillance testing of the full automatic functions of the EDG fuel oil transfer pumps was identified (Condition Report (CR) 2012 01324). However, procedure changes made in 1990 removed the test of the automatic start of the fuel oil transfer pumps on low level in the fuel oil day tank. Consequently, the EDGs cannot be considered operable because all auxiliary equipment to support operability has not demonstrated that it is fully capable of performing its safety function. This report is being made per 10 CFR 50.73(a)(2)(i)(B), 50.73(a)(2)(ii)(B), 50.73(a)(2)(v)(B) and (D), and 50.73(a)(2)(vii).
CONCLUSION
Prior to 1989, fuel oil transfer pump testing was included in the EDG surveillance procedures. The cause evaluation identified that the specific procedure steps to test the automatic start of the fuel oil transfer pumps on low level was removed by a procedure revision made in May 1990. Fuel oil transfer pump trip on high level remained in the procedure. The procedure change was prompted by a modification that replaced the fuel transfer pumps and added pressure gauges and flow rate meters.
Other procedure changes not pertinent to the modification were made at the same time. The additional changes included fully removing steps to place the fuel oil transfer pump transfer switches in AUTO for the purpose of testing. By operating the fuel oil transfer pumps in HAND, the length of the monthly EDG run would be shortened. The procedure revision summary did not provide discussion on the changes made beyond the scope of the modification. The FCS EDG configuration results in unavailability hours under the maintenance rule during surveillance testing, so reducing EDG run time would reduce unavailability time. The change was made 22 years ago, making it very difficult to reconstruct thoughts and discussions surrounding the procedure change. Clearly, there was a lack of understanding surrounding the purpose of the testing of the auto start feature of the fuel oil transfer pump, but there is no indication that the change was made to violate or circumvent TS requirements.
Several historical organizational and/or programmatic defenses may have failed. The procedure revision process used in the 1990s did not have the technical rigor that is currently employed at FCS.
In addition, the surveillance test program does not clearly link surveillance requirements to specific surveillance tests. Furthermore, the design basis document for the EDGs does not currently contain sufficient information on fuel oil transfer pump testing and verification.
The procedure changes made in 1990 removed the test of the automatic start of the fuel oil transfer pumps on low level in the EDG day tank. Without full testing of the automatic functions of the fuel oil transfer pumps, they cannot be considered operable. Consequently, the EDGs cannot be considered operable because all auxiliary equipment to support operability has not demonstrated that it is fully capable of performing its safety function.
The apparent cause of this event is a lack of technical rigor in the procedure change process employed in the 1990s.
Contributing causes are a lack of documentation indicating which surveillance tests satisfy specific technical specification surveillance requirements, and a lack of design basis information on verification methods for the fuel oil transfer pumps.
CORRECTIVE ACTIONS
1. Prior to plant restart, the Emergency Diesel Generator (EDG) surveillance tests will be revised to perform a test of the fuel oil transfer pumps ensuring auto operation is verified on a monthly basis.
This is an ongoing commitment.
2. Prior to plant restart, the EDG design basis document will be updated to include verification information for the diesel generator fuel oil transfer pumps. This is a one-time commitment.
SAFETY SIGNIFICANCE
Failure to fully test the automatic functions of the fuel oil transfer pumps renders the pumps inoperable. Therefore, consistent with the definition of OPERABLE, the EDGs cannot be considered operable as they rely upon the fuel oil transfer pumps to ensure an adequate fuel supply when the EDGs are performing their safety function. The EDGs have been technically inoperable in excess of TS allowed times. However, there is reasonable assurance that the EDGs and fuel transfer pumps would function as required as the low level switches are calibrated on a refueling frequency.
SAFETY SYSTEM FUNCTIONAL FAILURE
This event does result in a safety system functional failure in accordance with NEI-99-02.
PREVIOUS EVENTS
No previous events of a similar nature have been identified.
�� FORT CALHOUN STATION NOD-QP-9.2 �QUALITY PROCEDURE FORM RO
LICENSING CORRESPONDENCE REVIEW FORM
Date Issued:� 5/23/12 � LIC-12-0072 Requested Return Date:� 5/25/12 Review/Approval Information Susan Baughn Dave Bannister John Herman Woody Goodell Steve Miller Brad Biome Mike Smith Mike Prospero Corey Cameron Scott Pallas Kevin Naser Subject� LER 2012-005 Rev 1 "TS violation due to inadequate testing of DG fuel pumps" Please review and approve the attached draft correspondence (referenced above). I n order to document your review for our records, please sign this form and return it to the Licensing Coordinator. If n o notification is received by the requested return date, your concurrence with no comment will be assumed.
Erick Matzke/Sue Simpson� 6855 Technical Coordinator (Ext.)� Licensing Coordinator (Ext.) [ ] Approved with no comment.
� [ ] Approved pending resolution of comments as noted.
Comments:
Reviewer's Signature� Date � FORT CALHOUN STATION NOD-QP-9.2
QUALITY PROCEDURE FORM RO
LICENSING CORRESPONDENCE REVIEW FORM SUMMARY
LIC-12-0072 � Date Issued:�5/23/12 Requested Return Date:�5/25/12 Name Date Comments Received No Comments' Comments - How Resolved2 Susan Baughn 5/23/12 Corrected John Herman none Steve Miller 5/27/12 X Mike Smith none Corey Cameron 5/31/12 Corrected G. Papanic 5/24/12 Corrected Kevin Naser none Dave Bannister none Woody Goodell none Brad Biome none Mike Prospero none M. Cooper 5/31/12 Corrected M. Edwards 5/31/12 Corrected Subject: LER 2012-005 Rev 1 "Failure to Perform Monthly EDG Fuel Oil Transfer Auto Test" NOTE — This submittal does�does not�X include documents/files on CD-ROM.3 NL Comment Coordinator Signature Date Responsible Dept. Manager (if required) Date Review by Nuclear Licensing Supervisor Date 1 Attach only signed Licensing Correspondence Review Form.
2 Attach necessary documentation.
3 Ensure that the CD-ROM files are formatted properly for electronic information exchange (EIE) to the NRC. (Reference NL-17)