1.   The leak happened in the Pluto reactor building at Harwell in Oxfordshire.

2.   Energy Department officials said they traced the problem to the outside pipe after technicians found elevated radiation in part of the reactor building.

3.   Flaking paint chips could fall into drains and slow the flow of cooling water in the reactor building, he said.

4.   He said this reaction could also blow water from the filter building into the reactor building, where the remaining salt mixture is stored, allowing another chain reaction.

5.   Outside the reactor building, security is tight.

6.   So the water picked up more contamination from the floor of the reactor building before flowing into the Hudson.

7.   They said no radiation above normal background levels remained inside the reactor building.

8.   Williams said Drega worked in the turbine building, a radiation-control area, and not in the reactor building.

9.   Construction of the reactor building will start in August, Buerkle said.

10.   Operators were performing a test on the system that filters and removes radioactive materials that may be present in the reactor building, the company said.