05000305/LER-2009-001

LER-2009-001,

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3052009001R00 - NRC Website

Event Description:

At 13:58 CST on January 23, 2009 with the station at 100 percent power, Dominion Energy Kewaunee, Inc.

(DEK) was informed by the Nuclear Regulatory Commission that the station was not complying with Technical Specification (TS) 3.7.a.7.

At the time TS 3.7.a.7 stated for the emergency diesel generators (EDGs),[DG]:

TS 3.7.a.7 "Both diesel generators are OPERABLE. The two underground storage tanks combine to supply at least 35,000 gallons of fuel oil for either diesel generator and the day tanks for each diesel generator contain at least 1,000 gallons of fuel oil.

NRC staff determined that, without a siphon arrangement to equalize underground storage tank [TK] levels, Kewaunee Power Station (KPS) was not in compliance with the requirements of TS 3.7.a.7 that the EDG fuel oil storage tanks combine to supply at least 35,000 gallons for either EDG. In 1993, an evaluation determined the function of the siphon line was not required and other means could be used to transfer fuel oil between the underground storage tanks. Thus, DEK relied on a spare pump [P] to provide the combined fuel oil volume of at least 35,000 gallons. The use of a portable transfer pump was evaluated in 2008. The NRC determined that using a portable transfer pump was not consistent with the KPS licensing basis.

Therefore, compliance with TS 3.7.a.7 was not possible for the existing storage tanks without a siphon arrangement. Consequently, this condition rendered both EDGs inoperable.

With both EDGs inoperable, TS 3.0.c, "Standard Shutdown Sequence," was entered and preparations were being made to begin a plant shutdown.

In accordance with the guidance provided by NRC Inspection Manual, Part 9900: Technical Guidance, "Operations — Notices of Enforcement Discretion," dated February 7, 2005, DEK requested Enforcement Discretion from TS 3.7.a.7. At 15:42 CST on January 23, 2009, NRC verbally granted Enforcement Discretion to February 6, 2009. This period of 14 days was to allow time for NRC approval of proposed License Amendment Request 247 to reduce the required fuel oil volume for the seven day supply to the EDGs.

TS 3.0.c, "Standard Shutdown Sequence," was exited with there having been no reactivity manipulations.

Reactor power remained at 100 percent.

On February 6, 2009, NRC issued Amendment No. 203 that revised TS 3.7.a.7. The TS was revised from requiring "The two underground storage tanks combine to supply at least 35,000 gallons of fuel oil for either diesel generator and the day tanks for each diesel generator contain at least 1,000 gallons of fuel oil." to require each diesel generator's underground storage tank and corresponding day tanks to contain a minimum usable volume of 32,888 gallons.

The current TS 3.7.a.7 states:

TS 3.7.a.7 "Both diesel generators are OPERABLE and each diesel generator shall have:

A. Day tanks containing a minimum volume of 1000 gallons; B. An underground storage-tank and corresponding day tanks containing a minimum volume of 32,888 gallons of usable fuel; C. An OPERABLE diesel fuel oil transfer pump.

� The requirement to maintain a single failure design EDG syStem with sufficient fuel to operate for seven days is identified in ANSI N195-1976, "Fuel Oil Systems for Standby Diesel-Generators," section 5.2. DEK committed to meeting section 5.2 as part of its licensing basis when TS 3.7.a.7 was amended in 1989, ANSI N195-1976, section 5.2 states:

"The fuel oil system of single-unit nuclear stations shall be so designed that a single failure will not result in the loss of minimum diesel generator capacity. The on-site storage shall be sufficient to operate the minimum number of diesel-generators following the limiting design basis accident for either seven (7) days, or the time required to replenish the oil from sources outside the plant site following any limiting design-basis event without interrupting the operatibn of the diesel, whichever is longer.

In the ANSI Standard, "minimum diesel-generator capacity" is defined as: "The minimum electrical output from the diesel-generator to assure the operation of the minimum plant equipment required to prevent unacceptable consequences for any plant design basis event or accident condition.

DEK's position was that it could provide a seven day supply of fuel oil to either EDG, thus meeting TS 3.7.a.7.

With both EDGs inoperable based on the inability to meet TS 3.7.a.7, this condition is being reported pursuant to 10 CFR 50.73(a)(2)(i)(B), "Any operation or condition which was prohibited by the plant's Technical Specifications.

The overall safety significance is very small as discussed below.

The required minimum volume of fuel oil for the EDGs is sufficient to provide for seven days of continuous operation. Consistent with induS"try PRA models, the mission time for EDGs in the DEK Probabilistic Risk Assessment (PRA) model is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Within this time window, it is postulated that for all accidents and transients modeled in the PRA, a safe stable condition is reached. The administratively controlled amount of available fuel oil allows EDGs to be operated for a significantly longer time than the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> PRA mission time. Additionally, the offsite power non-recovery probability at seven days is negligible. Therefore, the above noncompliance with the 35,000 gallon requirement in TS 3.7.a.7 does not invalidate the PRA assumptions or assertions and there is no increased risk due to this noncompliance. The incremental conditional core damage probability (ICCDP) and the conditional large early release probability (ICLERP) are negligible.

Although unable to meet the requirement to automatically provide a seven day supply of fuel oil to one EDG given a single failure, ample time would be available to transfer onsite stored fuel oil manually to provide the seven day supply to one EDG.

Cause:

The licensing basis for the EDG fuel oil system was altered in 1993 by removing the function of the siphon line to provide an equal level in both underground storage tanks thus causing inability to comply with TS 3.7.a.7.

In, 2008, a temporary modification was developed that may have inappropriately approved the use of a portable transfer pump to maintain compliance with TS 3.7.a.7. A root cause is evaluating the condition, and if it is determined to be a cause of this event, a supplement to this LER will be made.

Corrective Actions:

License Amendment'No. 203 was approved by the'NRC on February 6, 2009 to identify fuel oil storage requirements that would provide for a seven day supply of fuel to either EDG without credit for connection between the two underground storage tanks.

Similar Events:

None �NRC FORM 366A (9-2007) PRINTED ON RECYCLED PAPER Serial No.09-195 cc: Regional Administrator, Region III U.S. Nuclear Regulatory Commission 2443 Warrenville Road Suite 210' Lisle, IL 60532-4352 Mr. P. S. Tam Sr. Project.Manager U.S. Nuclear Regulatory ComMission One White Flint North, Mail Stop 08-H4A 11555 Rockville Pike Rockville, MD,20852-2/38 NRC Senior Resident Inspector Kewaunee Power Station