Washington has given the OK for the Trojan reactor to be barged from Western Oregon to Hanford in one piece.

The reactor vessel - essentially the core with the insides intact but with fuel removed and the pipes cemented - already was scheduled to go to Hanford.

But Portland General Electric Co. wanted to change plans. Instead of chopping the vessel into 50 or more pieces and trucking it to Hanford, the company now plans to barge it in one piece in the second half of 1999.

The Washington Department of Health announced Tuesday its approval of the change. Other needed approvals already had been made by the Nuclear Regulatory Commission and the U.S. Department of Transportation.

The reactor vessel contains about 2 million curies of radiation - making it the most radioactive item to be buried at US Ecology's disposal site in central Hanford.

The reactor vessel is 43 feet long, 17 feet in diameter and weighs 1,020 tons. That makes it smaller than one of the more than 60 nuclear submarine reactor compartments barged from Puget Sound Naval Shipyard to Hanford for burial.

However, a typical Navy submarine reactor compartment contains about 60,000 curies with a maximum possible 86,000 curies. That's 23 to 33 times less than the Trojan reactor vessel.

The radiation from the Trojan reactor vessel falls within Hanford's permitted limits to be buried at the site.

PGE operated the 1,130-megawatt Trojan reactor near the Columbia River about 40 miles north of Portland from 1976 until late 1992, when repairing it was determined not to be economical.

PGE wanted to switch from trucking chopped reactor pieces to barging the whole vessel because:

Barging the reactor vessel in one piece would cost $23.8 million compared with an estimated 45 to 85 truck trips that would cost $38.4 million.

Shipping in one piece would trim the potential radiation exposure to workers chopping up the reactor vessel, the people transporting it and the public.