United States Nuclear Regulatory Commission

Office of Public Affairs, Region I

475 Allendale Road King of Prussia, PA 19406

Fax: 610/337-5241

Internet: dps@nrc.gov or nas@nrc.gov

I-98-46 April 28, 1998

Contact: Diane Screnci (610/337-5330) FOR IMMEDIATE RELEASE

Neil A. Sheehan (610/337-5331)

NRC PROPOSES $165,000 CIVIL PENALTY FOR BOSTON EDISON COMPANY

FOR VARIETY OF VIOLATIONS AT PILGRIM NUCLEAR POWER PLANT

The Nuclear Regulatory Commission has proposed a $165,000 fine against

Boston Edison Company for multiple violations of agency requirements at the Pilgrim

nuclear power plant. Boston Edison owns and operates the boiling-water reactor in

Plymouth, Mass.

Among the violations, identified during three NRC inspections conducted between

May 14, 1997, and January 6, are multiple failures to promptly find problems and/or

promptly and effectively correct them once discovered. In addition, the agency found

violations of the plant’s design control requirements.

Specifically, one of the violations stems from a modification to piping inside the

containment building, the large, protective reinforced-concrete structure that surrounds

the reactor and related components. The change, performed in 1984, involved the

installation of insulation on recirculation loop piping.

As a result of the modification, there was an increased probability of a malfunction

of emergency core cooling system pumps, which would be needed to keep the reactor

core covered and cooled following an accident, because of insulation debris collecting

on the pumps’ suction strainers. Boston Edison asserted that the increased pressure

that would exist inside the containment building in the aftermath of an accident would

prevent such clogging and ensure that the pumps would properly operate.

The NRC found that the utility failed to recognize the increased probability of a

malfunction and that the safety evaluation performed to support the modification

incorrectly concluded it could be implemented without first obtaining the NRC’s

approval.

Another violation relates to microprocessors used to control transformers which

provide power to safety-related instruments. The NRC found that a design flaw

introduced an unintended trip, or automatic shutdown, function into the computer
components. On April 1, 1997, that feature caused two transformers to lose power.

After that event occurred, the NRC determined that Boston Edison had not performed

an adequate safety evaluation to check whether the replacement of the

microprocessors could involve an unresolved safety question, or a problem that had not

been previously reviewed by NRC.

Lastly, the NRC found seven other violations involving problems that were not

identified and/or not corrected. The violations represent the utility’s failure to take

action to resolve programmatic weaknesses in its design control and safety evaluation

processes. They include:

ˇ Operation of the plant with salt service water system inlet temperatures that were

higher than design limits. The system uses water from the ocean to cool plant

components.

ˇ A single-failure vulnerability in the design of the salt service water system. The

NRC requires that plant systems have redundant, or backup, features so that if a

failure occurs they will not be rendered unusable.

ˇ A failure to translate into procedures the design requirement that non-essential

reactor building closed cooling water system loads be isolated during accident

conditions. The isolation would be needed to help prevent the escape of

radioactivity from the reactor building in the event of an accident.

ˇ A failure to adequately translate into procedures residual heat removal system

design flow rates for containment building heat removal. The system would be

used to cool the reactor and containment building following an accident. For

example, no analysis was performed to demonstrate that flow rates of greater

than 5,100 gallons per minute would not exceed the design limitations of the

system’s heat exchangers.

ˇ Deficiencies in emergency diesel generator loading calculations and procedures.

The generators would be needed to provide power to plant safety systems if offsite power was lost and must “load,” or energize, within a specified period of

time.

ˇ Operation of the emergency diesel generators at ambient temperatures higher

than the design limit.

ˇ Inaccuracies in the environmental qualification for electric equipment important to

safety located in the drywell, a cylindrical, concrete shield that surrounds the

reactor. Environmental qualification refers to the process of making sure

equipment would be able to operate despite the harsh conditions that would exist

following an accident.

In addition to the above Severity Level 3 violations (NRC violations range from
Severity Levels 1 to 4, with 1 being the most significant), the agency also cited the utility

for four Severity Level 4 infractions involving failure to report conditions outside of the

design basis of the plant. No fine is being issued in conjunction with those violations.

NRC Region 1 Administrator Hubert J. Miller, in a letter to Boston Edison

regarding the enforcement action, wrote that the agency was concerned the plant was

operated outside of its NRC-approved licensing bases because of “an apparent

fundamental misunderstanding of what constitutes a change to the design and licensing

bases. While there was no resultant adverse safety consequences in any of these

cases, the potential existed that, had a design basis accident occurred, safety-related

equipment and systems were not assured of accomplishing their design functions.

“Additionally,” Mr. Miller continued, “the failure to identify and/or correct these

conditions adverse to quality is of significant regulatory concern because the NRC relies

upon licensees to operate the plant within the approved licensing basis and to correctly

assess changes to the plant or its operations to assure that unreviewed safety

questions do not exist.”

Boston Edison has 30 days to pay the fine or to request in writing that all or part of

the penalty be withdrawn.

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