NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

OFFICE OF PUBLIC AFFAIRS, REGION IV

611 Ryan Plaza Drive - Suite 400

Arlington TX 76011-8064

No. IV-01-012 March 23, 2001

CONTACT: Breck Henderson

Phone: 817-860-8128

Cellular: 817-917-1227

e-mail: bwh@nrc.gov

NRC, NPPD TO MEET FOR REGULATORY CONFERENCE

ON POTENTIAL YELLOW FINDINGS AT COOPER NUCLEAR STATION

The U.S. Nuclear Regulatory Commission staff will meet Thursday, March 29, with officials of

Nebraska Public Power District, which operates the Cooper Nuclear Station near Brownville, Neb., for

a regulatory conference. The purpose of the conference is to discuss apparent violations involving the

installation of electrical connections to operate in a harsh environment.

The conference will begin at 1 p.m. on Thursday, at NRC’s Region IV office in Arlington,

Texas. The public is invited to observe the meeting, but participation will be limited to the NRC and

NPPD. NRC officials will be available to answer questions afterward.

The NRC has characterized the apparent violation to be discussed as having substantial safety

significance, and has designated it a potential “yellow” finding. Under the NRC’s new reactor

oversight process, inspection findings are evaluated under a significance determination process and

assigned a color that indicates safety significance. Findings with very low safety significance are

labeled “green.” “White” findings have low to moderate importance to safety and may require

additional NRC inspection. “Yellow” findings have substantial safety significance, and “red” findings

high safety significance. A more detailed explanation of the NRC’s new reactor oversight process can

be found on the NRC’s website at www.nrc.gov/NRR/OVERSIGHT/ROP/description.html.

In a nuclear plant, electrical cables to pumps, valves and other electrically-powered equipment

often must be spliced together. Splices, or electrical connections, require that the insulation protecting

the copper conductors be removed; however, these connection points need to be protected against

grounding in the high moisture and high temperature environment that could occur in the plant during

a serious accident. To replace the lost insulation, electrical connections are sealed with various types

of protective materials. The materials and methods of application used to seal electrical connections

must be designed and tested to certify that they provide protection against high moisture, high

temperature and high radiation conditions.

In March last year, near the end of a refueling outage, plant workers and NRC inspectors found

that the protective coverings on as many as 2,000 electrical connections in the Cooper plant may not

have been properly installed in a configuration that was tested and certified for the expected harsh

environment. As a result, the NRC determined that it could not be certain the connections were
protected, nor that important safety equipment would function in the event of an accident. The plant

remained shutdown from April 18 to May 26 while new protective coatings, properly qualified to

provide protection in a harsh environment, were applied to required electrical connections. The plant

returned to normal operation May 26. An inspection report completed in December identified the

problem as an apparent violation with substantial safety significance. That report is available on the

NRC Web site at www.nrc.gov/NRR/OVERSIGHT/ASSESS/REPORTS/cns_2000007.pdf .

A regulatory conference is being held to provide NPPD officials an opportunity to present

information to the NRC that will help it to reach a final determination of the significance of the

inspection findings. In addition to determining the significance of the findings, the NRC may also find

that a violation of NRC requirements occurred requiring corrective action by the plant’s managers.

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