It's a $20 billion question.

When Department of Energy officials say their new master plan for treating radioactive tank wastes is cheaper than the previous plan, are they comparing apples with apples?

Is the plan $20 billion cheaper? $19 billion? $17 billion? Or none of the above?

The question is important because DOE will be citing expected 25-year cost savings as it tries to get approval from Congress, state officials and the public over the next few years.

DOE's estimated savings have been received skeptically in the past few weeks during various public discussions.

The claim of $20 billion in savings has drawn criticism from two key Hanford Advisory Board members, who plan to discuss the matter today at the board's meeting in Portland.

HAB members Gerald Pollet, director of Heart of America Northwest, and Doug Huston, an official with Oregon's Department of Energy, contend DOE is using misleading figures in touting the predicted long-term savings.

Huston is chairman of the HAB's tank waste committee. Pollet is one of HAB's budget experts.

Hanford's original plan was to glassify its 53 million gallons of tank wastes under a so-called "privatization" concept.

Under that plan, contractors were to build and operate at least two generations of glassification plants through 2028 - or 2046, depending on which schedule DOE followed. The idea was that the contractors would only get paid as the wastes were processed.

But the added risks to the contractor and delayed payments added several billion dollars in financing costs to be paid off by 2011.

That cost scuttled that plan and led DOE to fire its original contractor, BNFL Inc.

DOE also is studying two possibly cheaper ways - bulk vitrification and steam reforming - to treat most of the remaining tank wastes by 2028. Those studies are supposed to determine by 2005 whether those alternatives are viable.

Pollet and Huston object that DOE is concluding it can save $20 billion over the privatization plan even though it doesn't really know how much the undeveloped new technologies actually will cost.

"It's an apples and oranges comparison. ... It's dismaying because it's misleading to the decision makers," Huston said.

Pollet said: "DOE's cost estimates for alternative technologies are unvalidated and have no degree of reliability at this point in time."

But DOE officials say they are focusing on different numbers than the HAB members. "There's been a lot of numbers out there over the years," said Howard Gnann, a senior technological adviser at DOE's Office of River Protection.

DOE recently recalculated its tank waste treatment budget estimates for the next 25 years. Depending on what assumptions are made, those calculations predict savings from $17 billion to $19 billion.

The $20 billion in savings quoted in recent HAB committee meetings apparently assumes a different scope of work.

DOE officials expect to spend $1.4 billion on developing the alternative technologies between now and 2028. They are expected to be drastically cheaper than using conventional glassification to treat the 21 million to 32 million gallons of wastes being considered for those technologies.

However, that estimate for development costs won't be more firm until 2005, when the alternative technology feasibility studies are done. Those studies also would produce better estimates for what the technologies would cost.