N.H. Reactor Is Started After 13 Years of Trouble

The Seabrook nuclear power plant began its first atomic chain reaction Tuesday, a pivotal event for a $6-billion project after years of delays, cost overruns and protests made it a focal point of the anti-nuclear movement.

Seabrook operators started sustained nuclear fission reaction in the plant’s 100 tons of uranium fuel at 5:23 p.m., officials said.

Completed in July, 1986, Seabrook received a federal low-power license on May 26, a day after a federal appeals court refused to block the tests.

Because of three faulty safety valves, initial atomic operations were delayed about a week. Preparations for the first fission reaction were resumed Monday.

Plant operators then withdrew control rods from the reactor’s fuel core and slowly began diluting the boron concentration in the reactor coolant water. Boron absorbs neutrons so they cannot strike and split uranium atoms to release more neutrons and trigger a chain reaction.

Seabrook was planned for commercial operation in 1979. A twin reactor was abandoned when it was 25% completed. Both reactors were to have cost less than $1 billion to build.

Protests since construction began in 1976 have resulted in more than 3,200 arrests. During two days of demonstrations earlier this month, 734 people were arrested.

Low-power testing must take place before a nuclear power plant may operate commercially, but before Seabrook can get a full-power license, it also must gain approval of evacuation plans for nearby beaches and communities up to 10 miles away.

Six Massachusetts communities are within 10 miles of Seabrook, but that state maintains that evacuation of the area would not be feasible. Federal hearings on evacuation plans that Seabrook has developed for Massachusetts are under way.

Seabrook’s owners also may have to prove they are financially qualified to run the plant commercially. The primary owner, Public Service Co. of New Hampshire, is under federal bankruptcy protection, and some of the 11 other utilities with Seabrook shares also have financial problems.

But the Nuclear Regulatory Commission ruled in December that those troubles pose no safety problem for low-power tests as long as the owners posted a bond to pay to decommission the reactor after the tests should it never operate commercially. Owners posted the bond last month.