05000244/LER-2004-001

LER-2004-001, Gaps in the Control Room Emergency Zone Boundary

Docket Number
Event date:	07-22-2004
Report date:	09-20-2004
2442004001R00 - NRC Website

I. PRE-EVENT PLANT CONDITIONS:

On July 22, 2004 the plant was in Mode 1 at approximately 100% reactor power. Control Room Emergency Zone (CREZ) boundary inspections were proceeding in conjunction with the Control Room Emergency Air Treatment System (CREATS) Modification per Plant Change Record (PCR) 2000-0024. The inspections included removal of portions of the building outer facade, and were being performed as part of an extent of condition evaluation from an earlier discovery of gaps .

totaling less than 5.25 square inches.

A. EVENT:

At approximately 0942 plant workers began to discover gaps between the control room floor and the east wall armor plate, eventually totaling approximately 117.7 square inches. This exceeded the 5.25 square inch limit, which correlated to the maximum analyzed unfiltered inleakage, and requiring that KI be credited as a compensatory measure to meet GDC 19 limits until the gaps were sealed. The gap size also exceeded the analyzed maximum size for toxic gas in-leakage concerns. However, toxic gas protection is not a technical specification (TS) requirement and no specific actions were required.

TO THE EVENT:

None

C. DATES AND APPROXIMATE TIMES OF MAJOR OCCURRENCES:

• July 22, 2004, 0942 EDST: Event Date and Time, discovery of gaps in the CREZ boundary.

• July 22, 2004, 1210 EDST: Gaps in the CREZ boundary sealed.

• July 22, 2004, 1352 EDST: Notification of event, event #40893, under 10CFR50.72(b)(3)(ii)(B).

D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:

None, since there were no failures of any components with multiple functions.

E. METHOD OF DISCOVERY:

The condition was discovered by plant workers performing inspections of the CREZ boundary.

F. SAFETY SYSTEM RESPONSES:

Safety systems were not required to function for this event.

III. CAUSE OF EVENT:

The cause of the event was incomplete sealing of the ballistic armor plate east wall of the control room during construction in 1978.

This event is NUREG-1022 Cause Code (B), "Design, Manufacturing, Construction/installation"

IV. ASSESSMENT OF THE SAFETY CONSEQUENCES OF THE EVENT:

This event is reportable in accordance with 10 CFR 50.73, Licensee Event Report System, item (a)(2)(ii)(B), which requires a report of, "Any event or condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degraded plant safety," and 10 CFR 50.73, Licensee Event Report System, item (a)(2)(v)(D), which requires a report of, "Any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to: ... (D) Mitigate the consequences of an accident.

The Ginna UFSAR section 6.4.2 describes the CREZ and associated systems. In general, the CREZ is part of the control building complex and functions to limit in-leakage to the control room during an accident to a value that, in conjunction with the CREATS, ensures the operator exposure will remain within prescribed limits. For a radiological event, analysis has shown that administering KI as a compensatory measure consistent with the provided guidance would maintain the overall operator dose below the limits for the design basis accident (DBA) by significantly reducing thyroid dose. Although not specifically credited as a compensatory measure until recently, KI had previously been available for use by the operators in the control room as deemed necessary by radiation protection personnel in an emergency. For a toxic gas event, Self Contained Breathing Apparatus (SCBAs) are readily available in the control room for operator use in the event a release occurred and in-leakage exceeded tolerable levels. Ginna procedures ensure a sufficient number of on-shift operators are trained and qualified on SCBA use to safely shut down the plant. Procedures also exist to direct operator actions in the event of a toxic gas release, including the use of SCBAs if control room habitability is affected.

Therefore, it was determined that the operators maintained the capability to perform their duties, and that the public's health and safety was assured at all times.

V.0CORRECTIVE ACTIONS:

A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL

STATUS:

The identified gaps were immediately sealed.

B. ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:

Ginna Station is currently undertaking a major effort to install a new CREATS system and upgrade the CREZ boundary. Work is progressing and if problems are discovered appropriate and timely corrective action is taken. The gaps in question were discovered as part of an extent of condition inspection from a previous discovery of gaps of less than 5.25 square inches. The plan is to complete this project and perform a tracer gas in-leakage test per Ginna's response to Generic Letter 2003-01, Control Room Habitability. A Control Room Integrity Program (CRIP) will also be implemented to ensure the CREZ boundary is maintained per design. This approach is consistent with Regulatory Guide 1.196, Control Room Habitability at Light-Water Nuclear Power Reactors.

VI.0ADDITIONAL INFORMATION:

A. FAILED COMPONENTS:

None

B. PREVIOUS LERs ON SIMILAR EVENTS:

An historical search of LERs was conducted with the following results:

Able to Mitigate the Consequences of an Accident Resulted in Plant Being Outside Design Basis Design Basis Other events/Action Reports (AR) related to the CREZ but not reported as LERs AR 2004-1634 - Gaps in the Boundary of the Control Room Emergency Zone AR 2004-1405 - Control Room Roof Leak in Northeast Corner AR 2003-3112 - Control Room Envelope (roof leak) AR 2003-1720 - Control Room Roof Leak AR 2003-1710 - Leakage Noticed From Control Room Ceiling AR 2003-0113 - Water Spots on Control Room Ceiling Tiles AR 2003-0073 - Water Damage to Control Room Ceiling Tiles AR 2001-1154 - 4 Leaks Found in the Control Room Air Handling Room AR 2001-2051 - Small Hole in Control Room Vent Ductwork C. THE ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) COMPONENT

SYSTEM REFERRED TO IN THIS LER:

COMPONENT� IEEE 803� IEEE 805 FUNCTION IDENTIFIER�SYSTEM IDENTIFICATION CREZ� SEAL� NA

D. SPECIAL COMMENTS:

None