The commercial nuclear reactor north of Richland has received its best report card from an industry group since 1984.

The Institute of Nuclear Power Operations gave the plant a score of 2 after an inspection in November. The institute rates commercial nuclear power plants on a scale of 1 to 5, with 1 being the best score.

"We're extremely delighted," said Don Carter, chairman of the Washington Public Power Supply System's Executive Board.

"This is a significant milepost on the way to becoming a premier plant," Carter said.

Out of the nation's operating nuclear plants, the industry group gave 27 a score of 1, while 28 got a score of 2. There were 12 plants that received a 3 and two plants with scores of 4. No plants received a 5.

The score will have some effect on reviews by the Nuclear Regulatory Commission, said Vic Parrish, chief operating officer for WPPSS.

He characterized the higher score as "a very significant measurement" that will be weighed by regulators in the federal agency.

WPPSS's scores from federal regulators have been improving, but the utility stumbled last summer when investigators found five operating mistakes at the plant.

None of the errors affected the safe operation of the plant, but they suggested serious weaknesses in procedures, the agency said. In November, nuclear regulators proposed a total fine of $100,000. WPPSS has not yet decided whether to appeal the fine.

The WPPSS plant received a score of 2 in 1984, during its first year of operation. The next score was a 4, given in 1985. Since then, WPPSS has been given 3s.

A score of 2 means a plant is "exemplary," while a score of 1 indicates excellence, according to the industry group.

A score of 3 means "performance is generally in keeping with the high standards required in nuclear power."

A score of 4 means "acceptable" performance but that improvements are needed.