SBIR-STTR Award

The end of the cold war has switched the focus from buildingweapons of deterrence to minimizing the chances for the use orproliferation of nuclear weapons. Thus, arms control verificationand the careful monitoring of the Nuclear Non-ProliferationTreaty are essential components of any international effort toassure safety from nuclear threats and security around the world.Success in verification and monitoring are only possible ifinstrumentation has adequate sensitivity for the radiation typeof interest and gives an unambiguous and immediate readout. Thereare practical requirements as well. The instrumentation should bereadily portable, should be easy-to-use, and should save theradiation fluence history for later analysis. It shouldcomplement other instrumentation designed to support theSafeguards Program of the International Atomic Energy Agency.Superheated drop (bubble) technology (SDD) promises suchcharacteristics and overcomes some of the limitations of gammaspectrometry and 3He coincidence counting. Phase I consists ofthe research and development that will consider the feasibilityof a small, microprocessorbased neutron spectrometer that willcount bubble events produced by neutrons. Spectrometry will beaccomplished by using SDD compositions possessing differentneutron energy thresholds. This system will complement gammaspectrometry in providing immediate display of the radiationfluence and flux as well as immediate or delayed downloading ofthe radiation record to a compact, battery-powered personalcomputer. From such records, on-site inspectors should be able tomake reasonable assays of the amount of plutonium present, withthe possibility of differentiating between spontaneous fissionneutrons and neutrons produced by a-n reactions. The entiresystem, which should fit in an attache-sized case, may also findapplication in lowlevel environmental monitoring of transuranicwastes.Anticipated Results /Potential Commercial Applications as described by the awardee: If feasibility is demonstrated, thenthe project will produce a compact and highly sensitivespectrometer for neutrons that will serve to alert inspectors tothe presence and amount of plutonium. Such instrumentation mayalso have applications for short-term, low level transuranicwaste monitoring and other environmental surveys of importance toDOE.

The non-destructive detection of plutonium 239 represents a substantial challenge for those agencies charged with the responsibility of monitoring the Nuclear Non-Proliferation Treaty. Confidence in the reliability of this process is essential if the treaty is to be renewed by its current signers in 1995, and if those who are currently not signers are to put their faith in the treaty. This challenge is augmented by the problem of monitoring the handling of nearly 200 tons of plutonium created by the superpowers during the cold war. A compact instrument is needed that will allow inspectors to determine reliably the presence or absence of plutonium at a given site, the approximate amount of plutonium at the site, and the nature of that plutonium (e.g. enriched Pu-239). Although gamma spectrometry is sometimes a logical choice for indicating the presence of plutonium, it several instances it may fail. In this project, a simple and compact system, based on superheated drop (bubble) technology, will be constructed that provides sufficient spectral information about the plutonium sources to permit appropriate plutonium classification. Tests performed during Phase I confirmed theoretical predictions of the feasibility of this methodology and allowed the selection of a particular pair of superheated drop compositions to be used in the construction of a plutonium neutron monitor. Circuity was designed, and software was tested. Phase II will continue the tests and construction of the instrument, with the goal of producing a fully operational prototype for testing at DOE sites.Anticipated Results/Potential Commercial Applications as described by the awardee:New instrumentation for plutonium monitoring will be developed that will assist in the effort of verifying compliance with the Nuclear Non-Proliferation Treaty and other nuclear arms control agreements. This instrumentation if modified, may also have application to environmental measurements of small amounts of plutonium in radioactive wastes.