At 0750 EDT on March 17, 2014, Operations determined that both the inner and outer
secondary containment airlock doors, on the 20 foot elevation of the Unit 1 reactor building, had been simultaneously opened for approximately 10 seconds. This event occurred while an employee was exiting
secondary containment immediately after another employee had previously entered. Upon recognition of the condition, the employees took action to secure both doors. The cause of this event was malfunction of the
secondary containment airlock door interlock.
This condition is being reported in accordance with 10CFR50.72(b)(3)(v)(C), event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material. With both doors open, Surveillance Requirement 3.6.4.1.3 of Technical Specification 3.6.4.1, Secondary Containment, was not met, rendering secondary containment inoperable. At the time at the time of the condition, Unit 1 was engaged in Operations with the Potential to Drain the Reactor Vessel (OPDRV) and was crediting Secondary Containment as Operable.
This event did not result in any adverse impact to the health and safety of the public.
The safety significance of this is minimal. Secondary containment was only inoperable for approximately 10 seconds. This event did not result in any adverse impact to the health and safety of the public.
The door interlock investigation [is] in progress. Doorwatches with communications have been stationed on either side of the Unit 1 and Unit 2 20 foot reactor building air lock doors. All other secondary containment access doors on both Reactor Building have been controlled as emergency exit only. Installation of temporary video surveillance system [is] being pursued until long term corrective action can be established per the corrective action program.
The NRC Senior Resident has been notified.
