SBIR-STTR Award

Phase I of this project initiates research to assess thepotential of radioisotope production and actinide wastetransmutation in small fusion reactors. High revenue radioisotopessuch as "P and "Cd as well as their production methods are beingidentified and investigated for a small experimental fusionreactor. The cost recovery aspect is being examined for thebenefit of a fusion energy development program. An innovativeconcept for the transmutation of actinide wastes-mainly 2"Np, 241@, and 211AM_is also being investigated. The conceptenvisioned converts the actinides to fissile nuclides by doublecapture reactions. An example is ... Np (n,gamma) 23ONP (betadecay) m8Pu (n,gamma) 239PU. Significantly higherreaction rates for these capture reactions are obtainable foractinide conversion and ultimate destruction at moderated neutronenergy range, compared with reaction rates for fission reactions athigh energy (as normally considered in previous studies). Theintermediate, nonfissile nuclides such as 23llpU in the case of"Np, act as catalysts during the transmutation process and maintaina constant inventory at equilibrium. The results of this studywill lead to the development of a viable fusion blanket foractinide waste transmutation at a relatively low neutron wallloading. Phase I efforts are analyzing the technical issues andidentifying developmental needs during the study period.Anticipated Results/Potential Commercial Applications as described by the awardee:The anticipated results of the research project are(1) incorporation of radioisotope production components in theplanning and design for the future experimental fusion reactors and(2) development of a small fusion power reactor devoted to actinidewaste transmutation.

Nuclear waste transmutation can be categorized into threescenarios: (1) fission products only, (2) minor actinides (Np,Am, and Cm isotopes) only, and (3) all transuranium isotopes. In Phase I nuclear performance characteristics for thefusion blankets constructed with ferritic steel dedicated for theabove transmutation scenarios were identified. For eachscenario, the desirable fusion power output of the fusiontransmutation reactors (FTRS) was estimated. The total thermalpower output of each scenario matches the 3000 MW(th) rating of atypical fission power plant (FPP), and the electric powerproduced is: Scenario 1 - about 3000 MW; Scenario 2 - about 300MW; and Scenario 3 - about 30 MW. These are determined based onthe blanket energy multiplication. The fusion power and plasmaamplification (Q) are likely to be important factors that willinfluence the economic aspect of the FTRS. Scenarios 2 and 3FTRs deserve further investigation because they requirerelatively lower fusion power and plasma Q. Scenario 3 (Alltrans-uranium elements (TRU) and fission products (FP) wastes)FTRs are the most attractive option, if (a) the FPPs are tomaintain the present U235 once-through cycle; and (b) only lowfusion power and low Q fusion reactors can be developed in theforeseeable near future. Scenario 2 (minor actinides andpossibly long-lived FPs) ETRs are the best if (a) the FPPs can @ethe Pu isotopes; and (b) modest fusion power output (about 300MW) and plasma Q (more than 1) are among the developmental goalsfor near-term experimental fusion reactors. 14C, 6OCo, 63Ni, and... TI can be attractively produced in an experimental fusionreactor. These radioisotopes are produced through thresholdreactions such as (n,p) and (n,a). "Co and 6Ni products fromfusion can have significantly higher specific activity thanconventionally produced in fission reactors because the parentnuclide, "Cu, is from a different element. Because of thesignificance of nuclear waste transmutation as a solution to thelong-term use of fission energy, Phase II will focus on the tasksrelevant to the development of fusion transmutation reactors.Phase II will develop viable transmutation blankets (particularlyScenario 2 and 3 type) for the FTRS. It will specify theperformance of tokamak FTRs facilitated with these blankets,identify cost-effective, near-term technology based small tokamakfusion reactors for achieving this performance, and examine theeconomic merits of these FTRS.Anticipated Results/Potential Commercial Applications as described by the awardee:The economic aspect of the nuclearenergy system with the planned FTR will depend strongly on theavailable fusion driver. A fusion driver with 50 to 300 MWfusion power, and break-even or better plasma Q, will be the mostdesirable for the development of FTRs to destroy all TRU and FPwastes. If successfully developed, the FTR will help to solvethe environmental issues associated with the use of fissionnuclear energy. The small fusion power reactor can also providesubstantial amount of 14 MeV neutrons for nuclear technologytesting for fusion energy development.