Information Notice No. 90-34: Response to False Siren Activations

                                UNITED STATES
                           WASHINGTON, D.C.  20555

                                May 10, 1990



All holders of operating licenses or construction permits for nuclear power 


This information notice is intended to alert addressees to potential 
problems resulting from lack of appropriate response to false alert and 
notification system (ANS) siren activations (false alarms).  It is expected 
that recipients will review the information for applicability to their 
facilities and consider actions, as appropriate, to avoid similar problems.  
However, suggestions contained in this information notice do not constitute 
NRC requirements; therefore, no specific action or written response is 

Description of Circumstances:

Between January 1987 and December 1989, more than 20 false alarms of the ANS 
were reported to the NRC.  These false alarms were attributed to such causes 
as inclement weather, mechanical failure, radio interference and personnel 
error.  In many cases, licensees and local officials responded to these 
actuations inadequately with regard to reassuring the affected public. 

For example, on June 2, 1989, at 4:49 a.m., spurious actuation of an 
emergency notification siren associated with the Diablo Canyon Nuclear Power 
Plant resulted in a high level of frustration and anxiety among members of 
the public when they were unable to confirm what action, if any, they should 
take.   Again, on January 16, 1990, at 11:20 p.m., a 20-minute spurious 
activation of an emergency notification siren associated with the San Onofre 
Nuclear Generating Station caused a similar reaction. 

In both cases, members of the public tuned their radios to the designated 
emergency broadcast station (EBS), which did not inform them that the alarm 
was false.  Members of the public subsequently called the licensee's 
emergency phone number listed in their emergency information booklet, but 
received no response since that number is only activated in a real 
emergency.  Members of the public then inundated their local 911 emergency 
number, overloading that system and frustrating local officials who also did 
not know what was 


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happening.  Some individuals attempted to call the licensee directly and 
some called the NRC Operations Center, with nobody being able to provide 
factual information. 

Licensees and local officials found, in one case, a failure to develop 
effective plans to respond to spurious activations and, in the other case, a 
failure by offsite organizations to implement planned responses. 

Diablo Canyon completed a root-cause analysis of the occurrence and with 
local authorities developed the following corrective actions: 

1.   A new section titled "Accidental Siren Sounding" was added to the 
     public's emergency notification booklet.  This section includes a 
     telephone number (manned by company employees 24 hours per day) that a 
     member of the public can call if he or she hears a siren but can find 
     no message on an EBS.  The new section also asks the public to refrain 
     from calling 911 when a siren sounds. 
2.   The licensee developed a training video tape for local officials and 
     for personnel at all EBSs. 

3.   Local officials revised their procedures and retrained individuals 
     responsible for activating the EBS.

In addition, because six spurious activations occurred since 1984, the 
licensee decided to upgrade the siren system.  The licensee is replacing all 
transistors in the sirens because these have been the most frequent cause of 
false activations.  The licensee is also modifying each siren to confirm 
activation if the siren sounds.  This modification was considered necessary 
because citizens have occasionally confused police or fire sirens with 
activations of the plant's emergency notification system.  


A similar information notice, Information Notice No. 81-34, "Accidental 
Actuation of Prompt Public Notification System," was issued on November 16, 
1981.  A siren, designed to warn of a nuclear emergency, sounding in the 
night would be expected to cause anxiety, which in turn leads to numerous 
unnecessary and burdensome calls to the local police, the licensee, and the 
NRC.  Timely and appropriate response to false alarms can reduce the level 
of public anxiety.  Failure to rapidly inform the affected public as to why 
the siren is sounding raises that anxiety.  Local procedures for response to 
false alarms have not been established in all cases.  Insufficient response 
may decrease public confidence that the ANS will perform its intended 
function during an emergency.  

Addressees may wish to verify that plans are in place to respond effectively 
to spurious activation of emergency notification sirens associated with 
their facilities. 


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This information notice requires no specific action or written response.  If 
you have any questions about the information in this notice, please contact 
the technical contact listed below or the appropriate NRR project manager. 

                              Charles E. Rossi, Director 
                              Division of Operational Events Assessment
                              Office of Nuclear Reactor Regulation

Technical Contact:  G. P. Yuhas, RV
                    (415) 943-3748

Attachment:  List of Recently Issued NRC Information Notices

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