THE DANGERS OF SHIPPING VITRIFIED HIGH-LEVEL RADIOACTIVE WASTE:

AN UPDATE

Edwin S. Lyman, PhD

Scientific Director

January 10, 2000

Vitrified high-level radioactive waste (VHLW) is produced by converting highly radioactive liquid waste, which results from the reprocessing of spent nuclear fuel, into glass logs.  The logs are encased in stainless steel canisters.  Each log weighs nearly half a metric ton and contains as much as 600,000 curies of radioactive fission products.  The VHLW shipment currently underway consists of 104 canisters packed into 4 shipping casks.  We estimate that the total amount of radioactivity being carried by the Pacific Swan is approximately 50 million curies, including more than 14 million curies of the long-lived and highly radiotoxic isotope Cs-137.  For comparison, the core of a typical large nuclear power reactor contains less than 10 million curies of Cs-137 during operation.        

Prior to and after the first shipment of VHLW by sea in 1995, the Nuclear Control Institute (NCI) voiced its concern that these shipments are not being carried out in an acceptably safe manner, and that a potentially catastrophic risk of release of radioactivity could occur, resulting either from a shipboard accident (collision and/or fire) or from an act of radiological sabotage.  The safety and security issues that NCI has raised have still not been resolved, despite numerous requests to corporate and government authorities in France, Japan, the United Kingdom and the United States. 

The shippers of VHLW argue that an accident that could cause a significant radiation release from a VHLW ship is practically impossible.  However, the September 1999 accident at the JCO, Co. plant in Tokaimura, Japan has demonstrated that the nuclear industry is incapable of realistically assessing the risks it poses to the public through its activities.  Its overconfidence leads to shockingly sloppy practices which can culminate in disaster. 

New information has recently emerged that confirms NCI's concerns and raises new questions about the risks to the public and the environment posed by these shipments.  These issues include:

1)       The consequences of a loss of a VHLW cask in coastal waters:  A 1996 NCI study found that if a VHLW cask were lost in coastal waters because of a severe accident or an act of sabotage, radiological contamination of the marine environment could result, with significant health consequences to consumers of marine products in the region.  This contradicted the claims of the shippers of VHLW, who argued that the shipping casks are so robust that they would not leak.  And even if they did leak, British Nuclear Fuels, Limited (BNFL) claims in its public relations materials that if VHLW became "directly exposed to the sea … the effect … would be negligible."  These claims were seconded by the International Atomic Energy Agency. 

However, more recent information indicates that the shipping casks will leak if submerged in salt water, and that the health impacts on the public could be severe.

A 1998 analysis by the French safety organization IPSN concluded that if the TN28VT, the shipping cask used to transport VHLW, were lost at sea, the stainless steel grooves holding the lid seals in place could be washed away by the corrosive effects of seawater in a matter of months, allowing seawater to infiltrate the cask and radioactive particles to escape. [1]

Also in 1998, Sandia National Laboratories (SNL) in the U.S. published the results of its own calculations of the consequences of the loss of a single shipping cask containing twelve irradiated nuclear fuel assemblies in a coastal fishery. [2]   It confirmed that there would be very severe health consequences for the public from such an event.  For example, SNL calculated that the collective radiation exposure to the population could cause 27,000 to 31,500 cancer deaths over a 50-year period, comparable to the total number expected to be caused by the Chernobyl accident.  For the shipment of VHLW now underway, the radioactive content is about one dozen times greater than that of the SNL study, and the health consequences would be correspondingly worse.   Therefore, in terms of their potential consequences, these shipments are truly "floating Chernobyls."

2)       Sabotage attack on a VHLW shipping cask:  In addition to sinking the ship outright, a saboteur that gained access to the ship could convert a VHLW cask into a potent radiological weapon through a judicious application of explosives.  U.S. government studies at SNL have demonstrated that a cask could be penetrated by a shaped charge (an explosive that propels a metal jet through an object), but argue that the release would be limited because only the VHLW directly in the path of the jet would be shattered and become available for release.

In the context of the U.S. plutonium disposition program, SNL has identified a credible theft scenario in which terrorists intercept a shipping cask containing weapons plutonium immobilized in VHLW, penetrate the cask with a shaped charge, fill the cask cavity with a low explosive, and blow the lid off without damaging the contents.  However, it has not analyzed a radiological sabotage scenario in which the saboteur sets out to maximize the radiological release by filling the cask with high explosive through the penetration and blowing the cask apart, severely damaging and dispersing the radioactive contents.  This type of attack could cause much more severe health consequences to the public than the scenario that has been analyzed. 

Despite repeated requests from NCI, the U.S. government has not analyzed this more severe scenario, because it claims that such events are incredible.  (However, it has not explained why it believes this types of attack is less credible than the more difficult theft scenario outlined above).  Therefore, the extent of the damage that could result from a successful sabotage attack on a VHLW ship in the Panama Canal remains unknown.  Nevertheless, such an attack could cause the dispersal of a large plume of respirable radioactive particles over a distance of several kilometers.     

A severe accident or successful act of sabotage that caused the Pacific Swan to sink in the Canal or in the shallow waters surrounding it could have a devastating impact on the shipping, fishing and tourism industries in the region.  The government of Panama should request that a full environmental impact assessment be conducted before allowing these shipments to transit the Canal and Panamanian coastal waters.