By Ian Hoffman
Albuquerque Journal
1/14/99
In a top-secret ‘experiment, nuclear-weapons scientists in Los Alamos
want to explode an exotic kind of plutonium inside a containment vessel
of naval warship steel.
Details of the research remain classified. Yet by using such a rare
form of plutonium, scientists have revived speculation that they are building
and detonating full-scale mockups of the A-bombs inside modern thermonuclear
weapons. The test explosions never would shatter such a multitude
of atoms as to qualify as a true nuclear blast. But arms-control
advocates worry the experiments still could be valuable for refining nuclear
weapons and so could violate the intended spirit of a global ban on nuclear
testing.
"The only reason to do this is to create an exact copy of (the first stage
of a nuclear weapon)," said Greg Mello, head of the Los Alamos Study Group,
a Santa Fe disarmament group. "Anybody who can do this doesn't need
to worry much about the Comprehensive Test Ban."
Officials at Los Alamos National Laboratory and the U.S. Department of
Energy said Wednesday that the tests are not aimed at creating new nuclear
weapons, but ensuring that existing weapons will keep working as they
age or their parts are replaced. "These experiments are fully consistent
with the Comprehensive Test Ban Treaty. We are not planning these
experiments to investigate new designs," said a DOE official familiar
with the lab's plans. "These experiments are useful for understanding
the physical and chemical nature of plutonium."
Dates for the tests have not been set. Scientists will perform the
explosions inside a massive x-ray machine, most likely the Dual-Axis Radiographic
Hydrotest facility. The first of DARHT's two x-ray beams is scheduled
to start operating this summer. These machines let scientists film
the first billionths of a second as a weapon's heart is crushed by high
explosives. Weapons designers can use those "movies" to double-check
the computer codes and simulations that are taking the place of now-forbidden
nuclear tests.
This new series of plutonium tests was largely secret until the Defense
Nuclear Facilities Safety Board raised questions last month about the
experiments, referring to them only as a "new classified activity." Safety
board analysts worried LANL scientists might rush to perform the tests
without a full-blown safety review.
"Let me assure you that this is not the case," wrote Vic Reis, the DOE
s assistant secretary for defense programs, in a Dec. 17 letter to the
nuclear safety board s chairman, John T. Conway. The letter, obtained
by Mello's organization, suggests lab scientists want to detonate greater
amounts of chemical high explosives than previously used in the containment
vessels. The vessels have 2-inch walls of a special steel developed by
the U.S. Navy for the skins of combat ships and submarines. Safety
board analysts were concerned they might not have time to be sure the
vessels can lock in the exploding plutonium, a radioactive metal that
can cause lung cancer when inhaled.
The DOE rates the odds of a vessel failure at less than one in a million,
though some experts calculate a slightly higher risk. All agree
the consequences of a plutonium release could be dire for lab workers
and possibly residents downwind in White Rock and Santa Fe. A senior
DOE official promised Wednesday night that Los Alamos scientists will
not perform the explosive tests until the safety board is satisfied the
vessels would hold and lab workers are safe from exposure to plutonium.
"We will not go forward with these experiments without DNFSB approval
beforehand," the official said.
The explosions would mark a revival of LANL work from roughly a decade
ago with plutonium-242, a heavier isotope than the plutonium-239 used
in nuclear weapons. Plutonium-242 behaves almost identically to
weapons plutonium when imploded by high explosives except it takes several
times as much plutonium-242 to achieve a nuclear-fission explosion.
Plutonium-242 is also less radioactive. These factors make the unusual
metal an ideal stand-in for real weapons plutonium in explosive tests.
"It doesn t represent a safety problem for workers or the public," said Al Stotts, a DOE spokesman in Albuquerque.
Arms-control advocates like Mello remain suspicious. He argues that weapons
scientists don't need more familiarity with plutonium. "Somehow
the data from these cutting edge experiments will not be used to improve
the design capabilities? That's hard to believe," he said. "LANL is working
to make the test ban obsolete at least for us (the United States)."