Information Notice 2006-28, Siren System Failures Due to Erroneous Siren System Signal
| ML062790341 | |
| Person / Time | |
|---|---|
| Issue date: | 12/22/2006 |
| From: | Michael Case NRC/NRR/ADRA/DPR |
| To: | |
| Carla P. Roquecruz, 301-415-1455 | |
| References | |
| IN-06-028 | |
| Download: ML062790341 (4) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR SECURITY AND INCIDENT RESPONSE
WASHINGTON, D.C. 20555-0001
December 22, 2006
NRC INFORMATION NOTICE 2006-28:
SIREN SYSTEM FAILURES DUE TO
ERRONEOUS SIREN SYSTEM SIGNAL
ADDRESSEES
All holders of operating licenses or construction permits for nuclear power reactors, except
those who have permanently ceased operations and have certified that fuel has been
permanently removed from the reactor vessel.
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform
addressees of the possibility that some or all of the offsite notification sirens may become
inoperable if an erroneous siren system signal is continuously sent. 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
required.
DESCRIPTION OF CIRCUMSTANCES
As a result of an NRC Emergency Preparedness operating experience trend review from
October 1, 2003 through December 31, 2005, an issue was found regarding siren system
failures. There were three instances of siren system failures in year 2005, as reported per Title
10 of the Code of Federal Regulations (10 CFR) Section 50.72(b)(3)(xiii), that were caused by
an erroneous signal. These three instances occurred at plants Summer, Vogtle, and Crystal
River with associated Event Report Numbers 41755, 41813, and 42122.
Lightning Strike Causes Single Siren to Continuously Transmit Signal
On June 7, 2005, Summers Early Warning Siren System (EWSS) performed an automated poll
of active early warning sirens. The polling indicated that not all of the sirens had responded to
the automated signal. The licensees communications personnel manually polled the active
sirens and determined that twenty-eight (28) sirens were not responding. The licensee located
the faulty siren and disabled its radio transponder. This restored the other twenty-seven (27)
sirens to service.
During the evening hours of the event, a thunderstorm passed through the stations ten (10)
mile Emergency Planning Zone (EPZ). It was determined that the faulty siren had been struck
by lightning, causing the radio transponder to go into a continuous transmit mode. This errant
radio signal blocked the polling signal from the other twenty-seven (27) sirens. Based on the
licensees Communications Department Report, if the EWSS had been actuated, all sirens, except the faulty siren struck by lightning, would have been activated. However, the siren
feedback system may not have been able to determine if all sirens activated.
Continuous Transmitter Signal Causes Siren System Failure
On June 30, 2005, during Vogtles daily maintenance check of the Alert Notification Siren (ANS)
System, a siren technician discovered that the radio transmitter used to communicate with the
sirens was not available. Investigation revealed failure of an encoder that utilizes a T1 phone
line to send signals from a siren encoder to the transmitter. This failure produced a signal to
key the transmitter. After the transmitter is keyed for approximately 15 seconds, the transmitter
locks out and is no longer available for use. Since the transmitter was unavailable, all offsite
sirens became inoperable. The licensee made a notification per 10 CFR 50.72(b)(3)(xiii).
Single Siren Continuous Feedback Signal Renders Siren System Inoperable
On November 6, 2005, all offsite notification sirens for Crystal River Unit 3 were determined to
be inoperable. The licensee determined that a single siren failed sending a continuous
feedback signal that rendered all of the remaining sirens inoperable. The failed siren was
bypassed, thereby restoring the remaining sirens.
BACKGROUND
Section 50.54(q) requires nuclear power plant licensees to follow and maintain in effect
emergency plans that meet the standards in 10 CFR 50.47(b) and the requirements in
Appendix E to 10 CFR Part 50. 10 CFR 50.47(b)(5) states that Procedures have been
established for notification, by the licensee, of State and local response organizations and for
notification of emergency personnel by all organizations; the content of initial and followup
messages to response organizations and the public has been established; and means to
provide early notification and clear instruction to the populace within the plume exposure
pathway Emergency Planning Zone have been established. These requirements are amplified
in Appendix 3 of NUREG-0654 FEMA-REP-1, Criteria for Preparation and Evaluation of
Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power
Plants that states, NRC and FEMA [Federal Emergency Management Association] recognize
that the responsibility for activating the prompt notification system... is properly the responsibility
of State and local governments. NRC and FEMA also recognize that the responsibility for
demonstrating that such a system is in place rests with the facility licensee. The NUREG also
states, Wherever proposed as part of a system, subject to later testing by statistical sampling, the design concept and expected performance must be documented as part of plans submitted
by licensees, States, and local governments.
DISCUSSION
Alert and Notification System failures may result from an erroneous signal generated as a result
of equipment damage, a single point of failure or system maintenance activities. Prior
equipment and maintenance activity assessments may identify system vulnerabilities and
needed troubleshooting activities when determining system failure modes. These prior
assessments may prevent or shorten siren system failures.
The ANS system provides for the timely notification of the affected population within the plume
exposure pathway EPZ surrounding nuclear power reactor sites. The ANS system alerts the
public of the emergency and provides a means for public officials to distribute emergency
instructions and advisories. The ANS system may be a combination of fixed or mobile sirens, Tone Alert Radios (TAR), automatic telephone dialers, commercial broadcast media, and the
Emergency Alert System. FEMA advises the NRC on the status of offsite emergency planning, including the suitability of the ANS system. FEMA bases its finding of acceptability on the licensees ANS system design report
and the FEMA-REP-10, Guide for the Evaluation of Alert and Notification Systems for
Nuclear Power Plants. Furthermore, the NRC depends on FEMAs assessment of the
licensees commitments in the facility ANS system design report in finding that planning
standard 10 CFR 50.47(b)(5) has satisfactorily been met.
FEMAs determination that the ANS system is acceptable is based, in part, on commitments
made by the licensee in the ANS system design report. The NRC expects licensees to ensure
that these ANS system program commitments continue to be met. Additionally, licensees are
reminded that, according to 44 CFR 350, significant changes to the ANS system require
FEMAs review and acceptance prior to implementation.
RELEVANT GENERIC COMMUNICATIONS
IN 2005-06, Failure to Maintain Alert and Notification System Tone Alert Radio Capability, was
intended to ensure that licensees using TARs maintain positive control over the distribution of
the TARs.
IN 2002-25, Challenges to Licensees Ability to Provide Prompt Public Notification and
Information During an Emergency Preparedness Event, addressed challenges related to the
ANS system, including failure to test and maintain personal home alert devices.
CONTACT
S
This information notice does not require any action or written response. Please direct any
questions about this matter to the technical contacts listed below.
/RA/
Michael J. Case, Division Director
Division of Policy and Rulemaking
Office of Nuclear Reactor Regulation
Technical Contacts:
Edward W. Robinson, NSIR
Robert E. Kahler, NSIR
(301) 415-1022
(301) 415-2992 E-mail exr2@nrc.gov
E-mail rek@nrc.gov
Note: NRC Generic Communications may be found on the NRC website, http://www.nrc.gov, under Electronic Reading Room/Document Collections. Emergency Broadcast System. FEMA advises the NRC on the status of offsite emergency
planning, including the suitability of the ANS system.
FEMA bases its finding of acceptability on the licensees ANS system design report
and the FEMA-REP-10, Guide for the Evaluation of Alert and Notification Systems for
Nuclear Power Plants. Furthermore, the NRC depends on FEMAs assessment of the
licensees commitments in the facility ANS system design report in finding that planning
standard 10 CFR 50.47(b)(5) has satisfactorily been met.
FEMAs determination that the ANS system is acceptable is based, in part, on commitments
made by the licensee in the ANS system design report. The NRC expects licensees to ensure
that these ANS system program commitments continue to be met. Additionally, licensees are
reminded that, according to 44 CFR 350, significant changes to the ANS system require
FEMAs review and acceptance prior to implementation.
RELEVANT GENERIC COMMUNICATIONS
IN 2005-06, Failure to Maintain Alert and Notification System Tone Alert Radio Capability, was
intended to ensure that licensees using TARs maintain positive control over the distribution of
the TARs.
IN 2002-25, Challenges to Licensees Ability to Provide Prompt Public Notification and
Information During an Emergency Preparedness Event, addressed challenges related to the
ANS system, including failure to test and maintain personal home alert devices.
CONTACT
S
This information notice does not require any action or written response. Please direct any
questions about this matter to the technical contacts.
/RA/
Michael J. Case, Division Director
Division of Policy and Rulemaking
Office of Nuclear Reactor Regulation
Technical Contacts:
Edward W. Robinson, NSIR
Robert E. Kahler, NSIR
(301) 415-1022
(301) 415-2992 E-mail exr2@nrc.gov
E-mail rek@nrc.gov
Note: NRC Generic Communications may be found on the NRC website, http://www.nrc.gov, under Electronic Reading Room/Document Collections.
ADAMS Accession Number: ML062790341 OFFICE
DIRS:IOEB
TECH EDITOR
NSIR:DPR
NSIR:DPR
PGCB:DPR
NAME
CPRoquecruz
CBladey (by email)
ERobinison
RKahler
QNguyen
DATE
10/17/2006
9/29 /2006
10/17/2006
10/23/2006
12/07/2006 OFFICE
PGCB:DPR
TL:DIRS:IOEB
BC:NSIR:DPR
BC:ADRA:DPR
D:DPR
NAME
CHawes
JThorp
EWeiss
CJackson
MCase
DATE
/ /2006
11/01/2006
10/23/2006
12/21/2006
12/22/2006 OFFICIAL RECORD COPY