05000286/LER-2005-001

LER-2005-001, Plant in a Condition Prohibited by Technical Specifications due to Error Making Control Room Ventilation System Inoperable

Docket Number
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2862005001R00 - NRC Website

Note: The Energy Industry Identification System Codes are identified within the brackets {}.

DESCRIPTION OF EVENT

On January 26, 2005, at approximately 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br />, with steady state reactor power at 100W, the Indian Point Energy Center (IPEC), Systems Engineering Department (SE), determined that the Control Room Ventilation System (CRVS) {VI} damper B {DMP} was operating with linkage in the reverse position.

Condition Report CR-IP3-2005-00315 was written to document this event. The event was determined to be reportable under 10 CFR 50.73(a)(2)(1)(B), a violation of Technical Specifications, at approximately 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on January 27, 2005.

The CRVS is divided into two trains with each train consisting of a filter booster fan {FAN} with associated inlet damper and the following components which are common to both trains: the control room filter {FLT} unit (consists of two roughing filters, two high efficiency particulate air (HEPA) filters and, two activated charcoal adsorbers {ADS}); manual outside air isolation damper; damper A (filter unit bypass for normal operation), damper B (filter unit inlet for outside air makeup), damper C (filter unit inlet for recirculated air), and the toilet and locker room exhaust fan. The CRVS is an emergency system, parts of which are in service during normal unit operations.

The CRVS has three different air flow configurations. Normal operation uses the air conditioning fans to supply about 1500 cfm of outside air through damper A and re-circulates about 8500 cfm of air. The 10 Percent Incident mode isolates damper A, provides unfiltered air recirculation by two safety related air conditioning fans, and uses a booster fan to both recirculate and filter about 1000 cfm through damper C and take in 35 to 400 cfm of outside air through damper B. The 100 Percent Incident mode isolates outside air by closing dampers A and B, provides unfiltered air recirculation by one of two safety related air conditioning fans and uses a booster fan to recirculate and filter air through damper C. The 10 Percent Incident mode is for radiological events and the 100 Percent Incident mode is for chemical and smoke events.

On May 5, 2001, damper B was replaced in its entirety and a new linkage was installed. The linkage was not installed properly at this time. When damper B was in the open position the linkage was installed in the reverse or closed position. As a result of this installation, when the damper received a close signal it further opens from the incident mode position and when it received an open signal, it closes, but only to the preset incident mode position. Activation instrumentation was not affected. This is not detectable by indication since the damper indication was set following installation of the arm based on the expected position (i.e., it was set to show open when it is closed and closed when it is open). This damper position error was identified on January 26, 2005 during the performance of tracer gas testing of the unit 3 Control Room (CR) {NA}. An evaluation established that the apparent cause of this error was incomplete work instructions in that no details as to how to connect the linkage was included in the work package. These details were not available when the work package was issued.

The CRVS was post-work tested, using the test for TS Surveillance Requirement 3.7.11.4, to verify that the Control Room (CR)� {NA} experienced a slight positive pressure.� The system flows are determined at various locations of the CRVS during the surveillance to assure the required flow ranges for outside air and re-circulated air are met. The 10 Percent Incident mode surveillance flow requirements were met because damper B went from an open position to the 10 Percent Incident position while working in reverse rather than from closed to the 10 Percent Incident position.� The 100 Pecent Incident mode surveillance flow requirements were also met even though damper B went further open.� Engineering is currently evaluating how the surveillance flow requirements were met and how to assure that future post-work tests confirm that damper B is properly operating.

At the time of discovery the CRVS was out of service using a one time allowed outage time of 14 days for the performance of the tracer gas test.

Damper B was repaired in the normal course of events for that test (the test required damper B to be disabled and subsequently restored). There was only one damper B replaced so there is no extent of condition.

CAUSE OF EVENT

There were no details as to how to connect the linkage included in the work package since these details were not available at the time the work package was issued.� The apparent cause of this error was inadequate work instructions.� A contributing cause was the failure of the post work test to detect that damper B was not operating properly for the Normal and 100 Percent Incident modes.

CORRECTIVE ACTIONS

The following corrective actions have been or will be performed under Entergy's Corrective Action Program to address the cause and prevent recurrence:

• The damper was repaired and planning included the proper linkage detailed instructions in the repair package.

• An Entergy fleet procedure (i.e., EN-WM-105 Rev 0 - PLANNING) has been issued with a scheduled implementation date of May 15, 2005.� This procedure requires planners to use available resources (e.g., vendor manuals, drawings) to develop an understanding of equipment function and operational characteristics, to reference those in the instructions and to include drawings.

• Corrective action has been initiated to determine why the post work test in May 2001 did not detect that damper B was not operating properly for the Normal and 100 Percent Incident modes and to initiate corrective action on how to determine the damper is operating properly.�This is scheduled for May 1, 2005

EVENT ANALYSIS

This event is reportable under 10 CFR 50.73(a)(2)(i)(B), any event or condition that resulted in the nuclear power plant operating in a condition prohibited by TS. Damper B has been inoperable since May 5, 2001. The TS bases state that "The CRVS is considered Operable when the individual components necessary to limit operator exposure are OPERABLE in both trains." This includes damper B. The damper remained inoperable until repaired after entry into TS 3.7.11 condition C on January 25, 2005 to perform tracer gas testing.

A review was conducted of Licensee Event Reports (LER) in the past two years for non-compliance with TS. LER 2003-004 reported a TS non-compliance due to improper document use.

EVENT SAFETY SIGNIFICANCE

This event had no significant effect on the health and safety of the public.

There were no actual safety consequences because the plant was not challenged, while damper B was inoperable, by an actual event that could affect the habitability of the Control Room. Additionally, there was no loss of safety function for the CRVS. As demonstrated by surveillance test, the 10 Percent Incident mode flow requirements were met with the inoperable damper. During normal operation the open damper B would not affect charcoal filter operability since the dampers to the two booster fans were closed effectively eliminating flow.� The 100 Percent Incident mode, which was affected, is entered for toxic gas and smoke events, but is not solely relied upon to maintain CR habitability. The CR requires the use of self contained breathing apparatus, with backup air bottles, by CR personnel to maintain habitability for a toxic gas or smoke event. The close signal to damper B during the 100 Percent Incident mode would allow the introduction of a greater amount of toxic gas due to the damper opening. However, SCBA are donned prior to loss of habitability. The operators also had the manual outside air isolation damper available to isolate the CR (it is intended to be redundant to damper B should it fail). Therefore the function of the 100 Percent Incident mode was maintained. Since the CR functions were not lost, the event had no significant effect on public health and safety.