NRC Bulletin 79-18, Audibility Problems Encountered on Evacuation of Personnel from High-Noise Areas
Audibility Problems Encountered on Evacuation of Personnel from High-Noise Areas
August 7, 1979
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Bulletin 79-18: Audibility Problems Encountered on Evacuation of Personnel from High-Noise Areas
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
August 7, 1979
AUDIBILITY PROBLEMS ENCOUNTERED ON EVACUATION OF PERSONNEL FROM HIGH-NOISE
AREAS
Description of Circumstances:
In January 1979, a number of licensee personnel were engaged in routine
activities in the auxiliary building at the Florida Power Corporation,
Crystal River Unit 3 nuclear plant. While these individuals were working in
the auxiliary building, in a high-noise (fan) area, an unplanned release of
radioactive noble gases was detected by building monitors within the
auxiliary building at concentrations which caused the licensee to initiate
the facility emergency plan auxiliary building evacuation procedure. The
facility Emergency Officer (Shift Supervisor) assessed the monitor readings
and initiated an auxiliary building evacuation. The evacuation announcement,
made over the licensee's PA system, was not heard by the personnel working
in the high-noise area. Licensee personnel did evacuate the auxiliary
building upon observing that other personnel had left, and after calling the
control room to inquire if an evacuation had been initiated. During these
occurrences, licensee personnel were not exposed to quantities of
radionuclides above regulatory guidance. However, the potential existed for
inadvertent unnecessary exposure of individuals to radioactive materials.
Subsequent to the NRC followup inspection of this occurrence, Florida Power
Corporation initiated an assessment of this situation and performed an
engineering evaluation and identified several plant areas where the
annunciator system needed audibility improvement. The licensee has installed
a new auxiliary building evacuation tone signal and may add visual alarm
indicators in areas of very high noise.
Action to be Taken by the Licensees:
For all power reactor facilities with an operating license:
1. Determine whether current alarm systems and evacuation announcement
systems are clearly audible or visible throughout all plant areas with
emphasis on high-noise areas. Determination in high-noise areas must be
made with the maximum anticipated noise level.
2. Determine what corrective action is necessary to assure that areas
identified as inaudible areas in (1) above, will receive adequate
audible/ visual evacuation signals. In areas where adequate audible/visual
evacuation signals cannot be assured by hardware changes, determine
what additional administrative measures are necessary to assure
personnel evacuation.
3. Submit within 45 days of the date of issuance of this Bulletin, a
written report of the findings on item (1), and delineate completed or
proposed corrective actions per item (2). For operating facilities in
a refueling or extended outage, the written report must be submitted
within 30 days after plant startup following the outage.
4. For accessible areas, all corrective actions determined per item (2)
must be completed within 120 days of the date of issuance of this
Bulletin. For inaccessible areas, the written report must include a
time schedule for completion of corrective actions in this area.
Reports should be submitted to the Director of the appropriate NRC Regional
Office and a copy should be forwarded to the NRC Office of Inspection and
Enforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
For all power reactor facilities with a construction permit, this Bulletin
is for information only and no written response is required.
Approved by GAO, B180225 (R0072); clearance expires 7/31/80. Approval was
given under a blanket clearance specifically for identified generic
problems.