P. M. BRIEFING : Seabrook A-Plant Tests Delayed

CONCORD, N.H. — Three faulty safety valves at Seabrook nuclear plant have been returned to the manufacturer, further delaying the start of tests, a plant spokesman said today.

Operators of the $6-billion reactor, completed nearly three years ago but unlicensed for low-power tests until last month, had hoped to start the first fission reaction several days ago but say they now won’t be able to do so before at least the middle of next week.

Engineers had worked on the valves since last Friday when it was discovered that one of three in the auxiliary emergency feedwater system was opening too quickly.

Seabrook, originally planned for commercial operation in 1979, has faced repeated regulatory delays, cost overruns and protests that have made it a symbol for the nation’s anti-nuclear movement.