Event Notification Report for August 09, 2013

STORAGE RACKS DETERMINED TO BE IN AN UNANALYZED CONDITION

EVENT DESCRIPTION:

"At B&W's NOG-L [Nuclear Operations Group - Lynchburg] facilities, scrap and waste material is generated during fuel bearing operations. Certain streams are collected in favorable volume less than or equal to 2.5 liter containers and eventually transferred to the Drum Count Area for U-235 assay. Because the U-235 content of such containers is not known until they have been assayed, they are referred to as 'unknowns' and are subject to a bulk weight limit. These containers are limited to a maximum of 7,000 grams net weight (approximately 15 pounds). The unknowns are stored on designated less than or equal to 2.5 liter container storage racks.

"The construction of the storage racks controls the spacing between storage locations and the distance from the floor. The racks' materials of construction are credited as a fixed neutron poison. Some of the unknown racks are fitted with an additional poison plate which allows the rack-to-rack spacing to be reduced.

"On August 9, 2013, at approximately 1:00 p.m., a contract Nuclear Criticality Safety (NCS) engineer working with B&W's NCS staff identified a safety concern. While working to consolidate information in several Safety Analysis Reports, it was determined that the poisoned less than or equal to 2.5 liter storage racks fitted with a horizontal poison plate were improperly analyzed.

EVALUATION OF THE EVENT:

"The NCS evaluation of the poisoned less than or equal to 2.5 liter storage racks fitted with a horizontal poison plate was completed in October of 2000. The analysis was based on an evaluation of a poisoned transport cart completed earlier the same year. However, a review by the B&W NCS staff indicated the conclusions of this earlier analysis were not properly applied to the analysis of the poisoned less than or equal to 2.5 liter storage racks fitted with a horizontal poison plate. The racks were improperly analyzed.

"The requirement of 10 CFR 70.61 (d) states in part: '...the risk of nuclear criticality accidents must be limited by assuring that under normal and credible abnormal conditions, all nuclear processes are subcritical, including use of an approved margin of subcriticality for safety.'

"Further evaluation of the poisoned less than or equal to 2.5 liter storage racks fitted with a horizontal poison plate indicated that under optimal moderation the keff exceeds the safety limit of 0.95 in NRC License SNM-42. Therefore the performance requirement of 10 CFR 70.61 (d) was not maintained.

NOTIFICATION REQUIREMENTS:

"B&W is making this 24 hour report in accordance with 10 CFR 70, Appendix A, (b)(1) - 'Any event or condition that results in the facility being in a state that was not analyzed, was improperly analyzed, or is different from that analyzed in the Integrated Safety Analysis, and which results in failure to meet the performance requirements of 70.61.'

"There was no immediate risk of a criticality or threat to the safety of workers or the public as a result of this event. A portion of the storage locations in the poisoned less than or equal to 2.5 liter storage racks fitted with a horizontal poison plate were removed from service. This action was taken to restore compliance with the performance requirements of 10 CFR 70.61.

STATUS OF CORRECTIVE ACTIONS:

"An investigation of the root causes of this event is ongoing. Corrective actions will be determined as a result of the investigation."

The licensee has notified the NRC Resident Inspector.

RADIATION MONITOR OUT OF SERVICE

"During the performance of SP [Surveillance Procedure] 1027.2A, NMC Radiation Monitor Train A Calibration, Radiation Monitor R-21, Circulating Water Discharge Radiation Detector failed the source test point three times and was removed from service.

"R-21 has an emergency response function to provide indication of gaseous or liquid effluent release to the environment. This monitor has no compensatory measure that will allow timely classification of two NUE [Notification of Unusual Event] and Alert classifications when out of service.

"This is a priority 1 activity to repair the monitor. The repair activity is continuous and is in progress.

"There are not radioactive leaks that impact the Circulating Water System.

"The NRC Resident Inspector was notified."

AUTOMATIC REACTOR TRIP ON LOW STEAM GENERATOR WATER LEVEL

The loss of a non-vital 480v bus resulted in a feedwater transient that caused steam generator water level to lower below the automatic reactor trip setpoint. The reactor trip and plant response was uncomplicated with all rods being inserted into the core.

The auxiliary feedwater system automatically actuated and is currently being to used to feed the steam generators. Decay heat is being removed via the steam dumps to the condenser. No relief valves or safeties lifted during the transient. The plant is currently stable in Mode 3 at normal operating pressure and temperature and is in its normal shutdown electrical lineup. There was no impact on Unit 2 which is currently operating at 100% power.

The licensee has notified state and local authorities and the NRC Resident Inspector.

INOPERABLE CONTROL ROOM ENVELOPE

"In 2010, Control Room Envelope testing was conducted to satisfy SR 3.7.10.5 (this surveillance testing is required each 6 years). At that time, as a prerequisite, the surveillance procedure contained a step to add water to two floor drain loop seals that penetrated the Control Room Envelope; this practice was determined to be unacceptable preconditioning. Because the 2010 surveillance test was the first performance of this surveillance, the unacceptable preconditioning resulted in the following: a never-performed surveillance, failure to meet the associated surveillance requirement, and an inoperable Control Room Envelope. At 2028 CDT the station entered LCO 3.7.10, Condition B.

"The station has taken action to periodically add water to the loop seals; this practice validates the loop seals will remain full of water. This action ensures, through Engineering judgment, that the loop seals will perform their function and the Control Room Envelope will provide adequate protection to the plant operators.

"The NRC Resident Inspector was notified."

The floor drains are located inside the control room envelope near the control room chillers. Prior to this report, filling the loop seal was performed sporadically. The loop seal is now filled daily.

* * * UPDATE FROM STEVEN SKOYEN TO PETE SNYDER AT 2019 EDT ON 9/10/13 * * *

"On 9/10/13, the Tracer Gas Test of Control Room failed to meet its acceptance criteria for the surveillance test. The failure was due to three (3) doors with minor seal leaks and/or test uncertainty. The station is evaluating door repairs and test uncertainty.

"The actions for the test failure to offset the consequences of the inoperable Control Room Envelope have been modified to protect the operators with the use of SCBA's and Potassium Iodine (KI) in the event of a DBA.

"The NRC Resident Inspector was notified."

The R3DO (Lipa) was notified.