Event Notification Report for September 05, 2007

MODIFICATION TO PROCESS COMPUTER THAT IMPACT ERDS AND SPDS

"The Plant Process Computer System (Emergency Response and Data Acquisition System, 'ERDADS') will be taken out of service for an approximate 4 week period (on Unit 3) to implement a planned modification. The current ERDADS is being replaced on Unit 3 and a computer outage is required for the installation of the new ERDADS. During this time period ERDS and SPDS functions will not be available for Unit 3. Unit 4 will function normally after a modification (expected duration 6 hours) to the existing computer operating system software is implemented. Also, Unit 3 Regulatory Guide 1.97 category 2D containment temperature and power system indicators for motor control centers, batteries, and inverters will not be available in the Control Room, although other instrumentation is available to monitor these parameters.

"This is an 8-hour reportable event per 10 CFR 50.72(b)(3)(xiii) Major Loss of Assessment Capability. The operation of plant systems will not be affected due to this planned action. ERDS and SPDS parameters will be monitored by control board indications. Compensatory actions have been developed.

"Follow up notification to NRC will be given once Unit 4 ERDS and SPDS are returned to service."

The licensee notified the NRC Resident Inspector.

* * * UPDATE PROVIDED BY JIM SPEICHER TO JEFF ROTTON AT 1031 EDT ON 09/10/07 * * *

"The Plant Process Computer System (Emergency Response and Data Acquisition System, 'ERDADS') was taken out of service on both Unit 3 and Unit 4 in order to implement a planned modification on Unit 3. The current ERDADS system is being replaced on Unit 3 during the current Unit 3 refueling outage. In order to perform this replacement, ERDS and SPDS functions had to be temporarily removed from Unit 4.

"ERDADS and SPDS functions have been returned to service on Unit 4 and have been verified to operate correctly. The ERDS link for Unit 4 was satisfactorily tested on 9/7/07.

"The ERDADS replacement on Unit 3 will continue with an estimated completion on September 24, 2007."

The licensee notified the NRC Resident Inspector. Notified R2DO (S. Shaeffer)

* * * UPDATE FROM NIELSEN TO HUFFMAN AT 1642 EDT ON 10/10/07 * * *

"The Plant Process Computer System (Emergency Response and Data Acquisition System. 'ERDADS') was taken out of service in order to implement a planned modification on Unit 3. Replacement of the ERDADS system on Unit 3 is complete. The ERDS link for Unit 3 was satisfactorily tested on 10/10/07."

The licensee notified the NRC Resident Inspector. Notified R2DO (Desai).

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THIS IS NOT A NEW REPORT.

This event report was originally withheld from public release under the NRC's policy for protecting sensitive unclassified information. The NRC has reevaluated this policy and is now making this event report available to the public with suitable redactions.
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DEGRADATION OF ITEM RELIED ON FOR SAFETY

"I. EVENT DESCRIPTION
On August 22, 2007, in accordance with operational procedures, a pre-filter was removed from the saw enclosure ventilation in the [DELETED]. The filter was constructed with a paper core and metal housing, approximately [DELETED] high with a [DELETED] diameter. The calculated volume approached 23 liters. The weight gain measured on the filter at the time of removal was about [DELETED] grams.

"Nuclear Criticality Safety (NCS) was notified because the weight gain was more than expected. Net weight difference is often used as a conservative U-235 mass until acceptable accountability measurements are completed. Preliminary ESP-2 counting showed the filter was less than the standard for containers of this size. An RWP was approved to transport the filter to drum count in order to perform NDA counting. NMC [Nuclear Materials Control] subsequently provided a U-235 value of approximately [DELETED] grams based on the greater of two counts.

"II. EVALUATION OF THE EVENT
It was determined that the existing NCS analysis for fuel accumulation in glove box pre-filters defined a limit of [DELETED] in a glove box pre-filter with the requirement that filters be changed out at a documented frequency determined by specific operations performed in the glove box. There was an operational requirement to check the enclosure manometer to determine if the exhaust filters need to be changed, no minimum change frequency had been specified. It is unlikely that a large fuel quantity could collect on this filter - the saw cuts only a few grams from each element, most of the cut material is zirconium, and much of the fines are collected in the coolant which is changed whenever throughput approaches [DELETED]. It is probable that the filter would clog, as indicated by the manometer check, before accumulation approached the limit.

"On September 5, 2007, it was determined the requirement of the NCS analysis to implement a minimum change frequency for the saw enclosure filter had not been completed nor the ISA [Integrated Safety Analysis] been updated. Although there was no immediate safety concern and controls were in place, IROFS [Items Relied On For Safety] had not been fully implemented. The operation of the saw was suspended on 9/5/07 at 11:15 am until the procedures and ISA are revised to include the IROFS.

"III. NOTIFICATION REQUIREMENTS
BWXT is making this 24 hour report in accordance with 10 CFR 70.61, Appendix A, (b)(2) - Loss or degradation of IROFS that results in the failure to meet the performance requirements of 70.61.

"IV. STATUS OF CORRECTIVE ACTIONS
The operation has been suspended pending further investigation."

The licensee notified the NRC Resident Inspector.

* * * UPDATE ON 05/11/08 BY H. Crouch * * *

THIS IS NOT A NEW REPORT.

This event report was originally withheld from public release under the NRC's policy for protecting sensitive unclassified information. The NRC has reevaluated this policy and is now making this event report available to the public with suitable redactions.
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