To add to Jill's post:
DISPOSING OF HIGH-LEVEL WASTES
In 1997, in the 20 countries which account for most of the world's nuclear power generation, spent fuel storage capacity at the reactors was 148,000 tonnes, with 59% of this utilised. Away-from-reactor storage capacity was 78,000 tonnes, with 44% utilised. Annual arisings are about 12,000 tonnes. Final disposal is therefore not urgent.
[Sitting ducks? Assuming percentages are still about the same, at reactors around the world there is over 80,000 tonnes of nuclear waste sitting near reactors.]
- [Moving ducks] Since 1971 there have been some 7000 shipments of spent fuel (over 35 000 tonnes) over more than 30 million kilometres.
nsnfp.inel.gov
- This site shows D.O.E. (only) stats for Spent Nuclear Fuel, totalling 2479 metric tons storage, the bulk of it in Washington State at the Hanford facility (too close to home for me...)
eia.doe.gov
- Spent Fuel in Storage by State and Storage Site as of Dec 1998. Some 38,413 metric tonnes uranium plus far more in related assemblie, located in dozens of sites all over the country.
tis.eh.doe.gov
- [Properties of Uranium, it likes to catch fire...] Uranium in finely divided form is readily ignitable, and uranium scrap from machining operations is subject to spontaneous ignition. This reaction can usually be avoided by storage under dry (without moisture) oil. Grinding dust has been known to ignite even under water, and fires have occurred spontaneously in drums of coarser scrap after prolonged exposure to moist air. Because of uranium's thermal conductivity, larger pieces generally have to be heated entirely to their ignition temperature before igniting. Moist dust, turnings, and chips react slowly with water to form hydrogen. Uranium surfaces treated with concentrated nitric acid are subject to explosion or spontaneous ignition in air.
[imagine what a jet full of fuel might do. Also, in checking sites for discussions of fire fighting uranium / plutonium, the examples were all given for small samples, in contained environments, not a big outdoor site fully aflame ]
- Bulk or massive plutonium characterized as having a specific surface area less than 10 cm{sup 2}/g requires temperatures in excess of 400 degrees C to ignite. Many plutonium fires have occurred because samples containing finely divided metal have spontaneously ignited. Fires have not occurred with well- characterized metal existing in large pieces that have higher ignition temperatures. Thus, massive plutonium is not considered pyrophoric or capable of self-ignition.
[no problem if helped by a fuel fire.]
gulflink.osd.mil
Depleted Uranium Exposures to Personnel Following the Camp Doha Fire, Kuwait, July 1991
[interesting report; while the results suggest that exposure, while serious, was within permissible limits (for what they were able to measure), its clear from reading the report that any uranium fire is of concern. Note this wasn't tons of nuclear reactor waste either]
-- On July 11 and 12, 1991, a fire engulfed a motor pool at the U.S. Army’s Camp Doha, in Kuwait.
This fire engulfed combat-ready military vehicles, including M1A1 tanks, Bradley Fighting Vehicles, and
ammunition carriers, as well as stacks of stored ammunition. After the fire was out, this area remained
extremely hazardous because some of the ammunition had caught fire or exploded from the heat and
distributed unexploded ordnance (UXO) over a wide area. Although this UXO was far more hazardous
and seriously life threatening, another type of potentially hazardous material was also left behind: the
partially oxidized remains of DU penetrators from 120-mm series anti-armor rounds and the DU oxide
dust generated by the heat of the fire. Depleted uranium is a mildly radioactive material and a heavy
metal. This analysis of the Camp Doha fire focuses on the levels of DU to which workers may have been
exposed and the resulting radiological and chemical toxicological risks to personnel from this exposure.
royalsoc.ac.uk
More information on Depleted Uranium fires
· DU aerosols dispersed at all temperatures in the range 500–1000°C.
· Outdoor Burn (4) with temperatures up to 1100°C and cycling produced more oxide (~45%)
Chernobyl - A Summary
The safety failures resulted in two explosions which sent a shower of hot and highly radioactive debris into the air and exposed the destroyed core to the atmosphere.
Atmospheric releases
nea.fr
In the initial assessment of releases made by the Soviet scientists and presented at the IAEA Post-Accident Assessment Meeting in Vienna (IA86), it was estimated that 100 per cent of the core inventory of the noble gases (xenon and krypton) was released, and between 10 and 20 per cent of the more volatile elements of iodine, tellurium and caesium. The early estimate for fuel material released to the environment was 3 ± 1.5 per cent (IA86). This estimate was later revised to 3.5 ± 0.5 per cent (Be91). This corresponds to the emission of 6 t of fragmented fuel.
The initial large release was principally due to the mechanical fragmentation of the fuel during the explosion. It contained mainly the more volatile radionuclides such as noble gases, iodines and some caesium. The second large release between day 7 and day 10 was associated with the high temperatures reached in the core melt. The sharp drop in releases after ten days may have been due to a rapid cooling of the fuel as the core debris melted through the lower shield and interacted with other material in the reactor. Although further releases probably occurred after 6 May, these are not thought to have been large.
Graph: nea.fr
(Figure 3. Daily release rate of radioactive substances into the atmosphere (modif. from IA86a) )
nea.fr
(Map of main areas of contamination)
Outcome on citizens:
- More than 4,000 people who took part in the hasty clean-up have died, according to government estimates, and over 70,000 Ukrainians left fully disabled.
- Altogether, Ukraine's health ministry estimates that one in 16 of the population of 49 million is suffering from grave health disorders linked to the disaster with 400,000 adults and 1.1. million children entitle to state aid.
[mw: however in my research this morning I found many contradictory reports on the after effects, many suggesting it wasn't as bad as some reports suggest - although none suggest that the release was not a serious, grave situation.]
My bottom line: Chernobyl was a single reactor fire with a significant trans-national impacts including health and economic damage on a large scale; it seems that the fear of a spent fuel storage fire might in fact be much worse than a reactor accident of the scope of Chernobyl, if for no other reason that much more material is stored outside the reactor than within, but also due to the population densities and significant economic centres near many nuclear faciltiies. |
