Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1997. / Includes bibliographical references (leaves 98-100). / by David J. Grover. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1996. / Includes bibliographical references (p. 131-138). / by Daniel Timothy Moriarty. / Ph.D.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1996. / Includes bibliographical references (leaves 119-123). / by Sherry C. Wu. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1996. / Includes bibliographical references (p. 115-116). / by Mark van der Helm. / M.S.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1997. / Includes bibliographical references (leaves 85-86). / by Dennis William Klein. / M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1997. / Includes bibliographical references (leaves 137-140). / by Florinel Morosan. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references (leaves 75-77). / by William B. Gerber. / S.M.

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1967. / One blank page included in paging. Vita. / Bibliography: leaves 340-343. / Analytical methods are developed to simulate on a large digital computer the production and use of reactor neutron beams f or boron capture therapy of brain tumors. The simulation accounts for radiation dose distributions in tissue produced by fast neutrons and by neutron capture reaction products such as gamma rays, C -particles, protons, and heavy particles. These techniques are applied to optimize the effectiveness of the M.I.T. Reactor Medical Therapy Facility through a survey of the effects of neutron filters and of modifications to the beam collimation system. Neutron beams reflected from thin slabs of hydrogenous materials are shown to have an improved ability to effectively irradiate a deep tumor without destroying normal tissue above it because relatively few fast neutrons are reflected. Considerable improvements in thermal neutron distribution in tissue are shown to result from surrounding the head with a neutron-reflecting annulus to reduce lateral neutron leakage. A new numerical solution is obtained for the problem of neutron transport in finite thickness slabs with isotropic scattering. Gaussian quadratures are used to evaluate the neutron transport integral equations, yielding transmission, absorption, and reflection probabilities, and fluxes, as a function of collision number. Collision history correlations are devised which use only five paraeters to predict the fate of neutrons incident on an infinite slab having arbitrary thickness and neutron cross sections. A very fast multigroup neutron spectrum calculation is developed by combining collision history correlations with single-collision group transfer probabilities to directly obtain transmission and reflection matrices for multi-slab shielding problems. / Sc.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1999. / Includes bibliographical references (leaves 167-168). / Investigations of unplanned shutdowns at the Seabrook and the Pilgrim Nuclear Power Stations were carried out to improve the understanding of the cause of those events, which had been reported in Boston newspapers. Failures of turbine-generator systems and nuclear steam supply systems reduced plant reliability, while failures of safety-related systems did not. Risk analysis with fault tree modeling was carried out to quantify risk of major components in turbine-generator systems, and in nuclear steam supply systems. The risk was evaluated in terms of the frequency of unplanned shutdowns in order to identify which components are important to plant reliability, As a result, feedwater pumps, major valves installed on main steam lines, the chemical and volume control system, and switchyards are identified as risk significant components, Other equipment was also ranked according to their respective risk significance, Uncertainty analysis for failure rates of components was carried out using Monte Carlo approach to compare the result of fault tree analyses with historical data. Taking uncertainty into consideration, the analytical data and the historical data showed good agreement in regard to reliability over different time spans of operation, Maintenance practices for major components at the Seabrook Nuclear Power Station was investigated in order to correlate this practice and the components I risk significance. Some components, such as Feedwater Pumps and Main Steam Isolation Valves, are maintained by the condition-based methods; however, because they have high risk significance in terms of plant shutdowns, preventive maintenance is preferable for these components. / by Kenichi Tezuka. / S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1997. / Includes bibliographical references. / by James F. McCarrick. / Ph.D.