I
IONIZING RADIATION

TECHNOLOGY DESCRIPTION

Material to be irradiated is moved remotely inside a shielded chamber (cave) in containers or pumped in a pipe past an electron beam, an irradiation device containing a specific gamma radiation source such as Co-60, or a mixed radiation source such as a spent nuclear reactor fuel element to chemically change the contents to less complex materials and gases. The irradiations start at room temperature and pressure. However, the material irradiated may be heated slightly by the absorption of radiation and pressure may increase from the production of radiolytic gases. If the absorbed dose is sufficient to destroy the agent in the containers, then the containers can be sampled and either irradiated again or disposed of conventionally.

DEVELOPMENT STATUS

Techniques such as those needed for agent destruction axe not developed. Irradiation techniques for much lower dose rates than those required by the Army's Chemical Weapons Disposal Program have been developed in the food preservation industry and for the production of specialty polymers. A considerable development effort would be required to obtain 99.9999 percent destruction of agent, including the certification that the containers axe safe for direct handling.

APPLICATIONS TO CHEMICAL WEAPONS DESTRUCTION

There axe no reports in the technical literature indicating that full destruction of chemical agent has been achieved with ionizing radiation. Certain surrogates such as carbon tetrachloride, chloromethane, trichloroethylene, and hexachloroethane, have been irradiated with 9 MeV X-rays or 700 keV gamma rays to doses of 1,400 tads. In general, these



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OCR for page 271
Alternative Technologies for the Destruction of Chemical Agents and Munitions I IONIZING RADIATION TECHNOLOGY DESCRIPTION Material to be irradiated is moved remotely inside a shielded chamber (cave) in containers or pumped in a pipe past an electron beam, an irradiation device containing a specific gamma radiation source such as Co-60, or a mixed radiation source such as a spent nuclear reactor fuel element to chemically change the contents to less complex materials and gases. The irradiations start at room temperature and pressure. However, the material irradiated may be heated slightly by the absorption of radiation and pressure may increase from the production of radiolytic gases. If the absorbed dose is sufficient to destroy the agent in the containers, then the containers can be sampled and either irradiated again or disposed of conventionally. DEVELOPMENT STATUS Techniques such as those needed for agent destruction axe not developed. Irradiation techniques for much lower dose rates than those required by the Army's Chemical Weapons Disposal Program have been developed in the food preservation industry and for the production of specialty polymers. A considerable development effort would be required to obtain 99.9999 percent destruction of agent, including the certification that the containers axe safe for direct handling. APPLICATIONS TO CHEMICAL WEAPONS DESTRUCTION There axe no reports in the technical literature indicating that full destruction of chemical agent has been achieved with ionizing radiation. Certain surrogates such as carbon tetrachloride, chloromethane, trichloroethylene, and hexachloroethane, have been irradiated with 9 MeV X-rays or 700 keV gamma rays to doses of 1,400 tads. In general, these

OCR for page 271
Alternative Technologies for the Destruction of Chemical Agents and Munitions compounds were destroyed to better than 85 percent but not better than 99 percent. Compounds containing carbon-phosphorus bonds were harder to destroy. Furthermore, it is not known whether the products from irradiations are indeed less hazardous than the feed materials. The major advantage of the radiation technique is that disassembly may not be required to render the contents of rockets or mines harmless. However, there is no experimental evidence indicating that such a level of destruction has been achieved. BY-PRODUCTS AND WASTE STREAMS After irradiation, the components containing agent, propellant, or munitions will need to be analyzed to ascertain that they may be opened and the products of radiation collected for conventional destruction. Conventional destruction includes any of the oxidation techniques such as molten salt, high temperature steam, fluidized-bed oxidation, or catalytic oxidation. Note that these munitions containers may be under substantial pressure from radiolytic production of gases in the closed containers. Leakage of these gases and containment become major concerns. It is very doubtful that complete destruction of agent is achievable (i.e., 99.9999 percent). It is not dear what the radiation products will be. It is possible that two phases will be recovered, namely, a radiolyric gas and polymerized solids. ADVANTAGES AND DISADVANTAGES The procedures for destroying agent by using penetrating nuclear radiation such as gamma rays or X-rays have the advantage that they may not need reverse assembly of weapons. There should be no thermal effects, thus reducing the possibility of explosions. The disadvantages of irradiations of other than penetrating radiation is that disassembly will be required. Thus, mixed radiation from spent fuel elements, electron irradiation, or beta rays will require less absorbing matter between the radiation and the agent. Other disadvantages are that radiation embrittlement of containers may become a problem at very high absorbed doses, and in conjunction with radiolytic gases, containers may have to withstand high stresses in embrittled containers.

OCR for page 271
Alternative Technologies for the Destruction of Chemical Agents and Munitions DEVELOPMENT NEEDS Radiation devices that can emit high-energy ionizing radiation at high dose rates may need to be developed. This is needed to fully destroy the agents in their containers in a reasonable amount of time. Remote handling and sampling become secondary development criteria. Finally, the contents of the irradiated containers should be non hazardous and be able to be transported or otherwise destroyed on site. This final destruction would need to be experimentally verified because the composition of the products may be different from that obtained from other methods of destruction.