United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 95-36, Supplement 1: Potential Problem with Post-Fire Emergency Lighting

                                 UNITED STATES
                         NUCLEAR REGULATORY COMMISSION
                         WASHINGTON, D.C.  20555-0001

                                 June 10, 1997

                                             FIRE EMERGENCY LIGHTING


All holders of operating licenses or construction permits for nuclear power


The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to potential problems regarding emergency lighting
for plant areas needed for operation of post-fire safe-shutdown equipment and
in the access and egress routes.  It is expected that recipients will review
the information for applicability to their facilities and consider actions as
appropriate.  However, suggestions contained in this information notice are
not NRC requirements; therefore, no specific action or written response is


The NRC previously issued Information Notice (IN) 95-36 to alert addressees
regarding problems with the maintenance and operability of emergency lighting
and, in some cases, the failure to install emergency lighting units (ELUs). 
Since IN 95-36 was issued, additional problems with ELUs have been identified. 
This supplement discusses problems associated with failure to follow
procedures by engineering personnel, failure to take corrective actions, and
failure to follow vendor recommendations, which resulted in degraded or
inoperable ELUs.

Description of Circumstances

NRC fire protection inspections have identified problems with post-fire ELUs
at several nuclear facilities.  Although some of these problems were
documented in surveillance tests by licensee personnel, the problems remained
uncorrected because of ineffective engineering involvement, lack of corrective
actions, and poor root cause evaluations.  In addition, some licensees have
failed to include ELUs within the scope of the maintenance rule.  This
supplement describes some of these issues.  

Quad Cities 

In 1995, an NRC inspection of the ELU surveillance records revealed that the
licensee had not taken prompt corrective action to repair or replace 19 ELUs
that had been inoperable since December 1994 (Inspection Report 50-245/95-05
and 50-265/95-05 dated August 25, 1995 [Accession No. 9509080140]).  The
licensee had determined that the inoperability was 

9706040320.                                                            IN 95-36, Supp. 1 
                                                            June 10, 1997
                                                            Page 2 of 5

caused by failure to switch the ELUs off when taking electrical busses out of
service during an outage.  This failure caused some batteries to fully
discharge and resulted in weak batteries that failed to meet the licensee's 8-
hour discharge test.  The licensee also had not evaluated the significance of
operating without the 19 ELUs required by Section III, J., "Emergency
lighting," of Appendix R to Part 50 of Title 10 of the Code of Federal
Regulations.  In addition, a licensee walkdown inspection found that
approximately 70 percent of the ELUs used to light access pathways were not
properly positioned or directed.


During a 1995 inspection, the NRC inspector identified a number of ELUs with
low-voltage and low-electrolyte levels (Inspection Report 50-461/95-09 dated
July 14, 1995 [Accession No. 9507240437]).  A low-battery voltage reading had
been recorded by the licensee; however, the licensee did not evaluate or
identify these problems as adverse performance trends.  In addition, the
monthly surveillance functional test of safe-shutdown ELUs, required by the
licensee's procedures, was not performed for three months. 


In 1995, NRC inspectors and the licensee identified a number of issues that
indicated numerous problems with ELUs (Inspection Report 50-295/95-22 and 50-
304/95-22 dated December 19, 1995 [Accession No. 9601020271]).  The inspectors
also found that the licensee had not performed adequate corrective actions or
root cause evaluations.  The following is a summary of some of the findings,
which resulted in a civil penalty:

.     Surveillance data indicated repeated battery failures and addition of
      water to batteries.  However, the licensee failed to determine the root
      causes or take adequate corrective actions until the NRC inspector
      brought these issues to the licensee's attention.

.     Surveillance inspections performed between May 10 to September 6, 1994,
      documented that two emergency lights were on continuous fast charge (in-
      dicating a low-battery voltage condition or an unrechargeable battery). 

.     Lights were not illuminating, thus indicating bulbs had burned-out or
      batteries were weak.

.     At least 40 batteries had final voltages lower than the recommended
      manufacturer's standard of 5.25 volts (1.75 volts per cell) for a
      nominal 3-cell, 6-volt battery.  The surveillance procedures had not
      established final voltage acceptance criteria, for determining whether
      the battery failed, following an 8-hour battery discharge test.

.     The accuracy of the voltmeter used to record final terminal voltages was
      questionable.  The voltmeters were not calibrated and the readings were
      accurate only to the nearest 0.5 volt, although readings were recorded
      to the nearest 0.1 and 0.05 volt.

.     The electrical maintenance staff did not follow the procedural
      requirements to replace ELU batteries when the electrolyte levels were
      found below the cell plates or when at least two hydrometer discs were
      not floating. .                                                            IN 95-36, Supp. 1
                                                            June XX, 1997
                                                            Page 3 of 5

.     After the 8-hour discharge surveillance performed in 1995, electricians
      took the final voltage readings of the batteries with the ELU lamps
      turned off or with the ELU connected to the 120V-ac outlet.  In either
      case, the electricians took the voltage reading of the battery charger
      and not of the battery.  This practice resulted in final ELU discharge
      voltages that were equal to or higher than the initial voltage reading. 
.     Emergency lighting surveillance data were not available for inspectors'
      review because the licensee had discarded all surveillance records prior
      to March 1994. 

.     Some of the available emergency lighting surveillance records included
      questionable data.  Some 6-volt battery readings were recorded as being
      12-volt, and some 12-volt battery readings were recorded as being 6-

.     Other problems identified by the inspectors during the plant tours
      included dirty lamps that decreased the output of emergency lights,
      lights that were improperly aimed, and loose lamp pivot connections that
      resulted in incorrectly aimed lights.  

.     A previous NRC inspection report had already identified problems with
      low ELU battery voltage conditions and low electrolyte levels
      (Inspection Report 50-295/94-19 and 50-304/94-19 dated October 19, 1994
      [Accession No. 9411010020]).


In 1996, the NRC inspectors noted that the licensee had not established final
voltage acceptance criteria for determining the value of 6-volt ELU batteries
that would provide adequate 8-hour lighting (Inspection Report 50-263/96-02
[Accession No. 9604250264]).  The licensee's procedures stated that an
automatic switching device would disconnect the emergency lights when the
battery voltage dropped to 2.9 volts, plus or minus 10 percent, and that the
lights would be considered functional if the light continued to illuminate the
intended area or had not been shut off by the automatic switch.  The licensee
did not have supporting data to show that a voltage of about 2.9 volts would
sufficiently illuminate an access or egress route.  The licensee subsequently
changed the acceptance criterion to  5.25 volts.  


During an inspection in 1996, the NRC inspectors found that the licensee had
not performed the 8-hour discharge surveillance test of 47 ELUs required by
the licensee's procedures (Inspection Report 50-010/96-02, 50-237/96-02, and
50-249/96-02 dated May 20, 1996 [Accession No. 9605290171]). 


During an inspection in 1996, the NRC inspectors found that the licensee had
not included ELUs required by Appendix R within the scope of the maintenance
rule (Inspection Report 50-321/96-12 and 50-366/96-12 dated November 22, 1996
[Accession No. 9612020172]).  A violation of 10 CFR 50.65 was issued because
this system was relied upon to mitigate accidents or transients during
performance of abnormal or emergency procedures..                                                            IN 95-36, Supp. 1
                                                            June 10, 1997
                                                            Page 4 of 5


During an inspection in 1996, the NRC inspectors found that the ELUs used in
the licensee's emergency operating procedures (EOPs) was inappropriately left
out of the scope of the maintenance rule implementation program (Inspection
Report 50-245/96-09, 50-336/96-09, and 50-423/96-09 dated February 24, 1997
[Accession No. 9703070183]).  


The ELUs at nuclear plants usually consist of a 6- or a 12-volt battery, bulb
lamps, and a battery charger.  NRC requirements and guidelines for emergency
lighting in the event of a fire are contained in various documents including
Appendix R, "Fire Protection Program for Nuclear Power Facilities Operating
Prior to January 1, 1979," to 10 CFR Part 50; Appendix to Branch Technical
Position Auxiliary Power Conversion Systems Branch, "Guidelines for Fire
Protection for Nuclear Power Plants Docketed Prior to July 1, 1976"; and
NUREG-0800, Standard Review Plan."  The extent to which these requirements or
guidelines are applicable to a specific nuclear power plant depends on plant
age, commitments established by the licensee in developing its fire protection
plan, the staff safety evaluation reports and supplements, and the license
conditions pertaining to the fire protection plan.  In addition,  10 CFR
50.65(b) established the scoping criteria for structures, systems, or
components (SSCs) to be included within the maintenance rule program.  The
scoping criteria include nonsafety-related SSCs that are relied upon to
mitigate accidents or transients, or are used in the plant EOPs, or whose
failure could prevent safety-related SSCs from fulfilling their safety-related
function. Furthermore, NUMARC 93-01, "Industry Guideline for Monitoring the
Effectiveness of Maintenance at Nuclear Power Plants," which has been endorsed
by the nuclear industry and the NRC, states that nonsafety-related SSCs used
in EOPs are within the scope of the maintenance rule.

The objective of these requirements and guidelines for emergency lighting is
to ensure that in the event of a fire, plant personnel can access and operate
equipment and components that must be manually operated to effect safe plant
shutdown.  Because such activities may extend over a considerable period of
time both during and after the fire, 8-hour battery emergency lighting
capability is specified to allow sufficient time for normal lighting to be
restored, with a margin for unanticipated events.
.                                                            IN 95-36, Supp. 1
                                                            June 10, 1997
                                                            Page 5 of 5

This information notice requires no specific action or written response.  If
you have any questions about the information in this notice, please contact
one of the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.

                                                signed by S.H. Weiss for

                                    Marylee M. Slosson, Acting Director
                                    Division of Reactor Program Management
                                    Office of Nuclear Reactor Regulation

Technical contacts:  Rogelio Mendez, RIII
                     (630) 829-9745 
                     E-mail:  rxm@nrc.gov

                     Darrell L. Schrum, RIII
                     (630) 829-9741 
                     E-mail:  dls3@nrc.gov
Page Last Reviewed/Updated Monday, November 18, 2013