Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
SSINS No.: 6835
IN 85-74
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, DC 20555
August 29, 1985
Information Notice No. 85-74: STATION BATTERY PROBLEMS
Addressees:
All nuclear power reactor facilities holding an operating license (OL) or a
construction permit (CP).
Purpose:
This notice describes problems that have occurred with lead-acid station
batteries at several nuclear power plants. These problems were discovered as
a result of inspections by the NRC Performance Appraisal Team (PAT). It is
expected that recipients will review the information for applicability to
their facilities and consider actions, if appropriate, to preclude a similar
problem occurring at their facilities. However, suggestions contained in
this information notice do not constitute NRC requirements; therefore, no
specific action or written response is required.
Description of Circumstances:
All four recent inspections by the PAT identified problems with lead-acid
station batteries. Although all of the problems are not listed here, a
summary of a few of the more significant problems with lead-acid station
batteries that were identified as a result of these inspections is provided
below:
Cooper PAT Inspection (November 1984):
The battery rated-load discharge test was performed at a discharge rate
significantly less than the manufacturer's recommended rated-load discharge
rate for the 8-hour period of the test. The licensee had no records of
battery charging following the completion of battery discharge test and
consequently the time and date the batteries were returned to service could
not be determined. The licensee failed to correct specific gravity
measurements for electrolyte temperature and level. The licensee had no
written procedures for conducting charges of the station batteries.
McGuire PAT Inspection (February 1985):
Three cells were placed on single-cell chargers for about 2 years, thus
raising questions regarding the operability of the battery and electrical
independence and separation of the Class 1E dc power systems. The cells on
single cell
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IN 85-74
August 29, 1985
Page 2 of 3
charge were at voltages higher than specified in the vendor manual. Although
one cell in the battery was jumpered out, the float voltage for the entire
battery was not reduced; consequently each cell was floated at a voltage
higher than specified in the battery vendor manual. The battery performance
discharge test was performed improperly because the test was stopped before
reaching the minimum specified voltage.
Susquehanna PAT Inspection (February 1985):
There were no station procedures for maintaining station batteries in
accordance with the battery vendor's manual or IEEE Std 450-1975, "IEEE
Recommended Practice for Maintenance, Testing and Replacement of Large Lead
Storage Batteries for Generating Stations and Substations" (which is
endorsed by Regulatory Guide 1.129, "Maintenance, Testing and Replacement of
Large Lead Storage Batteries for Nuclear Power Plants"). Intercell
resistance values were not compared with previous values to determine when
corrective action was required. The licensee did not always conduct
equalizing charges when required; nor did the licensee have procedures for
monitoring the progress of an equalizing charge or determining when the
charge should be terminated. Surveillance procedures for the 60-month
rated-capacity discharge test did not conform to IEEE Std 450-1975 because
the test was terminated at the end of 8 hours, instead of when the terminal
voltage fell to the minimum specified value (usually 1.75 volts per cell).
The licensee's procedures did not require that the average specific gravity
be calculated and compared to the technical specification acceptance
criteria.
San Onofre PAT Inspection (March 1985):
During the first 2 years of operation, the battery capacity tests required
by the Final Safety Analysis Report (FSAR) and IEEE Std 450-1980 were not
performed on Units 2 and 3. The total battery float voltage was not adjusted
to account for two jumpered out cells. The two jumpered out cells did not
receive the manufacturer's specified surveillances, maintenance, or charges.
The pilot cells were not being changed on a yearly basis, as recommended by
the vendor's technical instructions. The station engineer responsible for
the technical aspects of battery operation, maintenance, and surveillance
did not receive surveillance results and data sheets on a routine basis.
Discussion:
Recent IE inspections of operating facilities indicate that several
widespread deficiencies may exist in the operation and maintenance of
station batteries. These deficiencies are attributable to a variety of
causes, including licensee error, inadequate knowledge of batteries by
maintenance technicians and supervisors, and inadequate procedural guidance.
The results of these inspections suggest a general lack of appreciation
amongst licensee personnel for proper maintenance and surveillance of
station batteries. Although batteries contain no moving parts, considerable
care and attention to detail is required to maintain them operable. Too
often, licensees may be treating these vital engineered safety features
(ESF) power supplies as "passive" components and not providing them the
necessary management and technical attention.
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IN 85-74
August 29, 1985
Page 3 of 3
The following reference materials, provide guidance as to the individual
requirements for a facility's station batteries.
1. IEEE 450-1975, and 1980
2. Regulatory Guide 1.129, Rev. 1, "Maintenance Testing and Replacement of
Large Lead Storage Batteries for Nuclear Power Plants" (This regulatory
guide endorses IEEE Std 450-1975 with certain exceptions.)
3. Facility Technical Specifications
4. Final Safety Analysis Report (FSAR)
5. Station Battery Vendor Technical Manual (The vendor's of station
battteries periodically update their manuals to include revised
guidance.)
Other recent problems with station batteries were described in IE
Information Notice 84-83: VARIOUS BATTERY PROBLEMS, November 14, 1984.
No specific action or written response is required by this information
notice. If you have questions about this matter, please contact the Regional
Administrator of the appropriate NRC regional office or this office.
Edward L. Jordan Director
Division of Emergency Preparedness
and Engineering Response
Office of Inspection and Enforcement
Technical Contact: E. W. Weiss, IE
(301) 492-9005
L. J. Callan, IE
(301) 492-9497
Attachment: List of Recently Issued IE Information Notices