05000255/LER-2005-004
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2552005004R00 - NRC Website | |
FACIUTY NAME (1) DOCKET NUMBER (2) LER NUMBER (6 PAGE (3) 2005 — 04 — 00 I
EVENT DESCRIPTION
On April 18, 2005, with the plant operating at approximately 100% power, it was determined that plant procedures do not ensure that the fuel handling area ventilation system [VG] is aligned in accordance with Technical Specification (TS) 3.7.12, during the specified applicability conditions.
Subsequent evaluation of the previous three years identified two periods when TS 3.7.12 was not met. This occurred during core alterations and movement of irradiated fuel assemblies when irradiated fuel assemblies were present with than one week in duration and occurred in the Spring 2003, and Fall 2004, refueling outages.
TS 3.7.12 specifies that the fuel handling area ventilation system shall be operable, and in operation with one fuel handling area exhaust fan aligned to the emergency filter bank. The basis for TS 3.7.12 clarifies the intended ventilation system configuration as having all ventilation fans stopped, except for one exhaust fan operating, which is aligned to the emergency filter bank.
TS 3.7.12 was not met due to having more than the one specified exhaust fan in operation, aligned to the emergency filter bank, and also due to operating additional exhaust and supply fans in the fuel handling area ventilation system.
This is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by the plant's Technical Specifications.
CAUSE OF THE EVENT
The fuel handling area ventilation requirements, as currently specified by TS 3.7.12, were implemented in October 2000, as part of a major change from plant custom Technical Specifications to Improved Technical Specifications (ITS). Although this change was characterized as a more restrictive change at the time of ITS implementation, the specific change in wording that limited the ventilation system configuration to operation of only one exhaust fan was apparently overlooked.
SAFETY SIGNIFICANCE
This occurrence is of minimal safety significance.
The bounding fuel handling accident is assumed to occur in the containment building with no credit for containment isolation or for filtration of released fission products. Analysis has shown that the offsite dose resulting from this event is within the guidelines of 10 CFR 100.
FACILITY NAME (1)� DOCKET NUMBER�(2) LER NUMBER (6) PAGE (3) 2005 -- 04 -- 00 The consequences of a fuel handling accident in the fuel handling area are acceptable either with, or without the emergency filter bank in operation, since these consequences are no more severe than the consequences of the bounding fuel handling accident occurring in the containment building.
However, filtration through the emergency filter bank provides a significant reduction in offsite dose.
The procedure for responding to a fuel handling accident directs that the fuel handling area ventilation system be aligned in accordance with TS 3.7.12, with only one exhaust fan operating through the emergency filter bank, and with all other system supply and exhaust fans secured.
Therefore, following a postulated fuel handling accident, the correct fuel handling area ventilation system alignment would have been assured.
CORRECTIVE ACTIONS
Plant procedures will be revised to ensure that the fuel handling area ventilation system is aligned to correctly implement TS 3.7.12.
PREVIOUS SIMILAR EVENTS
Palisades Licensee Event Report 99-005, Charcoal Filter Not In Service During Movement Of
- Irradiated Fuel Assemblies