 INES 0 |
SALEM UNIT 1 LOSS OF CONTROL ROOM ANNUNCIATORS |
Salem Unit 1 was shutdown in a refuelling outage when control room operators discovered that the audible and visual main control board alarm annunciators had stopped responding. These annunciators alarm in the event of abnormal conditions or actuations of plant equipment. Within one hour, control room operators reinitialized the annunciator computer system and verified that the alarm annunciators were working properly. No plant systems were affected by the loss of alarm annunciators.
Basis for INES Rating of the Salem Unit 1 Alert on 04 OCT 1995
BACKGROUND:
On 04 OCT 1995, Salem Unit 1 was shutdown and defueled . The licensee declared an ALERT due to the loss of the audible and visual main control board annunciators. The loss of alarms was discovered during a preplanned nightly test procedure. Control room operators reset the annunciator computer system and restored the annunciators within approximately one hour. Loss of the annunciators did not affect the automatic initiation of any safety systems, nor the main control board display of safety system parameters.
RATING BASIS:
The event is rated "level 0, below scale" in accordance with Paragraph III-2.3 of the INES User's Manual. This paragraph defines the levels of safety function availability used in rating events. Table I of the INES User's Manual provides INES rating factors based upon the level of safety function availability. This event had no effect on safety-related equipment.
Event date: Wed, 04-10-1995
