Information Notice No. 81-34: Accidental Actuation of Prompt Public Notification System

                                                           SSINS No.: 6835 
                                                           Accession No.: 
                                                           IN 81-34 

                                UNITED STATES
                           WASHINGTON, D.C.  20555

                             November 16, 1981 

                                   NOTIFICATION SYSTEM 

Description of Circumstances: 

Recently the Maine Yankee prompt notification system was inadvertently 
activated. The Maine Yankee system consists of three subsystems, one of 
which uses radio controlled fixed sirens to alert the public to the 
existence of a regional emergency.  The regional emergency signal, which 
would be used in the event of an emergency at Maine Yankee or any other type 
of regional emergency requiring public notification, can be activated by 
Maine Yankee plant personnel, by the county Sheriff, and by the State 
Police.  In a regional emergency, all fixed sirens are activated 
simultaneously by a single radio signal carrying a two tone sequential 
command encoded at the transmitter and decoded at each siren's radio 
receiver.  The public has been instructed that when they hear the regional 
emergency alert signal, they should tune in the Emergency Broadcast System 
(EBS) and/or the local National Oceanic & Atmospheric Administration (NOAA) 
station to get information about the nature of the emergency and what they 
are to do. 

The fixed sirens can develop more than one sound.  In addition to a common 
regional emergency sound, each siren can also produce a different, 
distinctive sound which is used by local fire companies to signal a fire. 
The controls for fire calls are independent of the regional alert control. 
Recently the fixed sirens were activated three times in rapid succession by 
radio signals generated by the State Police in the course of routine police 
radio pager operations not connected with a regional emergency. 

For a time neither Maine Yankee personnel, the county Sheriff, nor the State
Police realized that the regional emergency signal had been triggered.  No 
emergency instructions or announcements were broadcast to the public via EBS
or NOAA, so some concerned citizens telephoned the plant and the State 
Police for further information.  In all, about one hour elapsed between the 
first siren system activation and the first media announcement indicating no
emergency existed. 

Since this event, the State Police, who have the authority to activate EBS 
and NOAA, have developed "no emergency" messages and procedures which can be
quickly aired should another emergency signal be produced in the absence of 
an emergency. They have also altered their radio operations plan to assure 
an offending signal will not be generated.  Maine Yankee has altered the 
tone sequencing scheme to render it unlike tone sequences typical of 

                                                          IN 81-34 
                                                          November 16, 1981 
                                                          Page 2 of 2 

available paging systems.  These steps will reduce the likelihood of a 
recurrence and provide for rapid announcements to the public over EBS 
stations and NOAA weather radio in the event a "no emergency" message is 
needed.  Thus, the "no emergency" message will reach the public in the same 
way emergency instructions would, and just as rapidly.  These are interim 

In the longer term, an encoded digital message will be used to activate the 
sirens.  This offers far more security than the sequenced tone system it 
will replace.  The "no emergency" announcement capability will be retained. 

This information notice is provided to make licensees and applicants aware 
of this event and its associated problems.  We expect that licensees will 
review this information for applicability at their facilities. 

No written response to this information notice is required.  If additional 
information is desired regarding this matter, please contact the Director of
the appropriate NRC Regional Office. 

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