UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555

November 4, 2004

NRC INFORMATION NOTICE 2004-19: PROBLEMS ASSOCIATED WITH BACK-UP

POWER SUPPLIES TO EMERGENCY

RESPONSE FACILITIES AND EQUIPMENT

ADDRESSEES

All holders of operating licenses 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 to alert

addressees to problems with back-up power supplies for emergency response facilities (ERFs)

and equipment. Emergency response equipment and ERFs need to be functional in the event

of an emergency. 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 are not NRC requirements; therefore, no

specific action or written response is required.

BACKGROUND

The ERF and emergency response equipment requirements must meet the following standard

of Title 10 of the Code of Federal Regulations (CFR), Part 50, Paragraph 47(b)(8):

Adequate emergency facilities and equipment to support the emergency response are

provided and maintained.

Requirements are also found in Section IV.E “Emergency Facilities and Equipment” of Appendix

E to 10 CFR Part 50:

Adequate provisions shall be made and described for emergency facilities and

equipment, including:

A licensee onsite technical support center (TSC) and a licensee near-site emergency

operations facility from which effective direction can be given and effective control can

be exercised during an emergency.

ML042730010
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DESCRIPTION OF CIRCUMSTANCES AND DISCUSSION

TSC Emergency Diesel Generator Switch Misalignment

On June 14, 2004, as a result of a loss of offsite power (LOOP) event at Palo Verde Nuclear

Generating Station, electrical power was lost to the TSC. The TSC diesel generator started as

designed, but subsequently tripped due to high engine temperature. During troubleshooting, it

was determined that the engine operating switch was in idle. With the switch in idle, the diesel

generator started on loss of electrical power to the TSC, but did not come up to proper voltage

and frequency and did not reenergize the TSC electrical distribution panel. As a result, the

engine radiator cooling fan did not start; therefore, the engine overheated and tripped on high

temperature. 

The licensee determined that the engine operating switch was apparently left in the idle position

following post-maintenance testing of the engine-starting system performed on June 8, 2004. 

After corrective maintenance was performed on one battery terminal and connector, the team

leader allowed the electricians to test the engine starting system without a working copy of the

test procedure in the field, since this test was routinely performed by the electricians. After the

diesel generator was successfully started, the engine operating switch was moved from run to

idle to allow the engine to run at a slower speed and cool down before being secured. A followup NRC inspection determined that the failure to have a working copy of the test procedure at

the engine during this post-maintenance testing and failure to use the restoration guidance

contained in the test procedure contributed directly to the failure to restore the TSC diesel

generator to its normal standby condition. The NRC inspection also determined that the diesel

generator failure contributed to a delay in staffing the TSC because the responding members of

the emergency response organization were moved to an alternate TSC. This issue was

documented in NRC Inspection Report 05000528/2004012; 05000529/2004012;

05000530/2004012. (ADAMS# ML042020061)

Procedural Changes Modifying the Effectiveness of the Emergency Operations Facility (EOF) 

On June 25, 2001, the NRC resident inspector at the Cooper Nuclear Station observed the

licensee’s response to an alert declaration due to a fire affecting the station startup transformer. 

During the event, the inspector noted that the EOF had no alternating current (AC) power. The

normal power supply to the EOF was deenergized when the startup transformer isolated

following an electrical component failure. As a result, the EOF had limited communication

abilities and emergency battery powered lighting. 

Although a back-up power supply existed for the EOF, it was only allowed to supply power to

necessary equipment when the plant was operating in Mode 4, cold shutdown or Mode 5,

refueling. In operating Modes 1, 2, and 3, power operations, startup, and hot shutdown,

respectfully, the back-up power supply was allowed to power only communication equipment

due to electrical loading restrictions on the switchgear. The NRC resident inspector determined

that this restriction significantly compromised the ability of the emergency operations facility to

adequately function following a loss of normal power in Modes 1, 2, and 3.
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In 1986, the licensee performed a design change to increase the reliability of the EOF and

provide a back-up source of power during a loss of offsite power event. This design change

originally placed no restrictions on using the back-up power supply to the EOF for any operating

mode. On September 14, 1991, the licensee revised a system operating procedure which

restricted the back-up power source to supply only the emergency operations facility

communication system when operating in Modes 1, 2, and 3, due to power limitations on the

electrical switchgear. This issue was documented in NRC Inspection Report 50-298/01-09. 

(ADAMS# ML043070372) 

Failure to Maintain the TSC Batteries

On December 11, 2003, the NRC completed an inspection at the Indian Point Nuclear

Generating Station, Unit 2. While reviewing condition reports, the inspection team noted that,

during the quarterly surveillance tests performed on October 21, 2003, one cell in each of the

two TSC battery banks did not meet the acceptance criteria specified in the test procedures. 

Although the cells were marginally out of specification, the team determined that the licensee

did not take prompt corrective actions either to return the two cells to within specifications or to

evaluate the impact of the out of specification conditions on the functionality of the battery

banks. Although the TSC battery banks performed as designed during the northeastern grid

blackout on August 14, 2003 (August 14 event), the team determined that the degraded cells

had the potential to adversely affect the facilities and equipment required to support emergency

response. This issue was documented in NRC Inspection Report 05000247/2004003. 

(ADAMS# ML040360248) 

Miscellaneous Failures During the August 14 Event

During the August 14 event, the TSC back-up diesel generator at Indian Point Unit 2 failed to

automatically start and subsequent operator actions to manually start and load the diesel failed. 

The Unit 2 TSC diesel generator failed to function due to electrical loading in excess of its

design capacity. This condition was initially identified in February 2000 and was not resolved in

a timely manner. Observations by the licensee during emergency planning training revealed a

potential for the TSC back-up diesel generator to be overloaded. Also, a review by the licensee

of the electrical power distribution drawings showed a potential existed for the TSC back-up

diesel generator to be overloaded under some conditions. Long-term corrective actions for this

diesel were postponed. The Unit 2 TSC and Operational Support Center remained without a

back-up AC electrical power supply until September 15, 2003, when a temporary alteration was

installed and satisfactorily tested. 

Additionally during the August 14 event, the Indian Point Unit 3 TSC back-up diesel generator

started and then tripped while being loaded and was unavailable for the duration of the

blackout. The Unit 3 TSC diesel generator failed to function due to a malfunctioning overspeed

controller. The diesel generator was repaired and restored to service on September 16, 2003. 

During a refueling outage, on April 18, 2003, the Unit 3 TSC back-up diesel generator was

tested under simulated blackout conditions and tripped while being loaded. Subsequently, a 
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licensee system engineer initiated a work order to replace a suspected faulty overspeed trip

module. Seven hours later, the Unit 3 TSC diesel was retested in an unloaded condition and

declared operable. The work order to replace the TSC diesel generator overspeed trip module

was postponed by the licensee’s maintenance planning organization until November 2003,

based upon a determination that the diesel problem was “not an operability concern.”

During an inspection at Indian Point Units 2 and 3, following the August 14 event, an NRC team

identified that the licensee did not have a preventive maintenance program in place to ensure

the continued functionality of the numerous Un-Interruptible Power Supplies (UPSs) in the EOF

which provide back-up power to emergency response equipment. By design, there is no

electrical back-up power supply to the EOF. Instead, the EOF has a number of UPSs which

provide short-term battery back-up power to dedicated ERF communications and data

transmission systems. During the August 14 event, the UPSs failed or functioned at only a

fraction of their design capacity.

The failures of the Unit 2 and 3 TSC back-up diesel generators and the EOF UPSs were

documented in NRC Inspection Report 05000247/2003013 and 05000286/2003010. (ADAMS#

ML033570386)

CONCLUSION

Problems with back-up power supplies and equipment have the potential to impact the ability of

ERFs to support a prompt and effective response to an emergency. The occurrence of these

types of problems can be reduced by following restoration procedures after testing and

maintenance, promptly resolving deficiencies identified during testing and maintenance, and 

reviewing design changes for impact on the operability of ERF back-up power supplies.

CONTACT

This information notice requires no specific action or written response. Please direct any

questions about information in this notice to the technical contact listed below or the appropriate

Office of Nuclear Reactor Regulation project managers.

/RA/

Patrick L. Hiland, Chief

Reactor Operations Branch

Division of Inspection Program Management

Office of Nuclear Reactor Regulation

Technical Contact: Jason L. Flemming

(301) 415-5787

E-mail: jlf2@nrc.gov

Attachment: List of Recently Issued NRC Information Notices
______________________________________________________________________________________

OL = Operating License

CP = Construction Permit

Attachment 1

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LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

____________________________________________________________________________________

Information Date of 

Notice No. Subject Issuance Issued to

____________________________________________________________________________________

2004-18 Recent Safety-related Event at

Panoramic Wet-source-storage

Irradiator

10/26/2004 All licensees authorized to

possess and use sealed sources

in panoramic wet-source-storage

irradiators, and irradiator vendors.

2004-17 Loose Part Detection and 

Computerized Eddy Current

Data Analysis in Steam

Generators

08/25/2004 All holders of operating licenses

for pressurized-water reactors

(PWRs), except those who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor.

2004-16 Tube Leakage Due to a

Fabrication Flaw in a

Replacement Steam Generator

08/03/2004 All holders of operating licenses

for pressurized-water reactors

(PWRs), except those who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor.

2004-15 Dual-Unit Scram at Peach

Bottom Units 2 and 3

07/22/2004 All holders of operating licenses

for nuclear power reactors except

those who have permanently

ceased operation and have

certified that fuel has been

permanently removed from the

reactor vessel.

2004-14 Use of less than Optimal

Bounding Assumptions in

Criticality Safety Analysis at

Fuel Cycle Facilities

07/19/2004 All licensees authorized to

possess a critical mass of special

nuclear material.

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