PORTLAND - The Hanford Advisory Board is antsy about the Department of Energy postponing a decision on whether to add extra low-activity waste melters to Hanford's tank waste glassification complex.

DOE plans to make that decision in 2005.

At that time, DOE will look at studies on using steam reforming and bulk vitrification to treat some of Hanford's low-activity radioactive tank wastes, and decide whether one or both of those methods will work.

If those two technologies cannot handle 40 percent to 60 percent of Hanford's 42 million gallons of low-activity wastes by a 2028 deadline, DOE will have to add extra melters to Hanford's glassification complex currently under construction.

Three to "several" extra low-activity waste melters could be needed through 2028, depending on how much waste cannot be handled by bulk vitrification and steam reforming, various Hanford officials said Thursday.

The needed number of extra low-activity waste melters will grow greater the longer that their construction is delayed, Hanford officials said.

DOE is supposed to receive study results on the feasibility of bulk vitrification and steam reforming in January 2005, which leaves the decision on how to treat a huge portion of the tank wastes in limbo until later in 2005.

The original glassification plan called for building one high-level radioactive waste melter and three low-activity waste melters by 2011, and building more at a later date.

The Tri-Party Agreement, the legal pact governing Hanford's cleanup, requires all 42 million gallons of low-activity wastes and 11 million gallons of high-level wastes to be glassified by 2028.

Some wrinkles have emerged in the past two years.

The two high-level melters will take care of the 11 million gallons of high-level wastes by 2028.

Meanwhile, DOE planned on sending 30 metric tons of low-activity wastes a day through the glassification complex, which originally needed three melters.

Design improvements mean that only two low-activity melters are needed to average 30 metric tons a day.

Consequently, DOE reduced the planned number of low-activity melters to be built by 2011 from three to two.

That decision sparked criticism from HAB members and regulators over keeping the third low-activity melter and glassifying more wastes versus only building two.

DOE's reply has been that the glassification complex's supporting equipment cannot handle more than 30 metric tons per day, so there will be only enough daily wastes for two low-activity melters.

On Thursday, Al Conklin of Washington's Department of Health said that the state granted DOE a permit to allow the glassification plant to emit effluents from glassifying 50 metric tons a day of low-activity wastes - enough for three melters with some extra cushion.

Greg Jones, executive officer of DOE's Office of River Protection, said the logistics and mechanics of moving low-activity waste to the melters, sending the material through the melters, and moving the wastes after glassification are what is limiting the plant to handling 30 metric tons a day.

He said that DOE originally requested that the state health department allow effluents from 50 metric tons a day as a cushion against unexpectedly increased emissions.

DOE plans to request the state to issue a new permit to reflect effluents from 30 metric tons of low-activity wastes per day.