Y2K Could Hit Nuclear Plants

Article excerpt

No one knows what will happen on January 1, 2000 because of the Y2K computer bug," Yumi Kikuchi observes, but "the prevention of nuclear hazards must be our top priority worldwide. We are calling for a temporary moratorium on all nuclear activities including reactors, fuel processing and atomic weapons. We named this the World Atomic Safety Holiday" (WASH).

The main goals of the WASH campaign:

* Reactor and nuclear processing facilities holiday from December 1, 1999 until after New Year's Day Each facility must show it meets Y2K compliance criteria with testing and verification before restart.

* Installation of added reliable back-up power systems, (turbines, fuel cells, or renewable sources) and certification that diesel generators are in good working order with a minimum three-month supply of fuel.

* De-alerting of all nuclear weapons no later than December 1, 1999.

Mary Olsen of the Nuclear Resources Information Service (NIRS) warns that unless all of the world's 433 nuclear plants operate flawlessly during the millennial leap, reactor accidents could "make the Y2K `time bomb' a nuclear disaster."

Every one of these plants must be ready for January 1, 2000 and testing must be subject to third-party validation. Olsen warns that simply "turning the reactor off will not remove the hazard completely"

Y2K failures could affect a nuclear reactor in multiple ways. First, a digital component failure might trigger a reactor failure directly (This is a big problem for Japan -- the only country that no longer has manual back-up control for its reactor systems.)

More indirectly, bad data might cause a reactor operator to take inappropriate actions, which could cause an accident.

The third type could happen if the electricity fails. Reactors depend on off-site electric power to run cooling systems and control rooms, with emergency diesel generators for automatic backup. Unfortunately, according to Olsen, even in the US these generators are "not even 90 percent reliable."

In the US, most local emergency officials are planning for three weeks without power. But diesel generators often overheat and usually are not operated for weeks at a time. Many generators also have digital components that may be subject to Y2K failure.

"It takes only two hours without the cooling system functioning for reactor fuel to melt," Olsen says. Power failures also could cause "a meltdown of nuclear fuel storage pools.... These pools must be cooled for at least five years."

Loss of off-site electrical power poses the most prominent risk to nuclear powerplant safety. Reliable back-up power is needed immediately at each nuclear site. Fuel cells and gas turbines are more reliable than diesel generators.

There are well over 1,000 private utilities, non-utility generators, public utilities, and rural electric cooperatives in the US and Canada operating more than 15,000 generating units. Many will reach the millennium with Y2K issues unresolved.

The US electric power grid is fragile. In 1996, two disruptions in one five-week period caused 190 generating stations (including several nuclear reactors) to shut down. …