Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1984. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 412-425. / by Shih-Kuei Cheng. / Ph.D.

The 2018 Draft Integrated Resource Plan (IRP) published by the Department of Energy (DoE) of South Africa informs the government’s electricity demand projections until 2050. They are published under the authority of the Electricity Regulation Act (ERA) of 2006. The Electricity Regulations on New Generation Capacity of 2009 stems from the ERA. The draft IRP must, however, be seen in the context of previous IRPs, and policy considerations outlined in Chapter 2. The draft IRP 2018 sets out to estimate the generating capacity requirements and allocates how much of each energy technology will be commissioned during the projection window. The rollout of the nuclear component of the IRP has had many challenges since the first original IRP was published in 2010. Apart from varied policy jockeying regarding the various energy sectors in South Africa (SA), court cases and other factors, allegations of corruption and maladministration have caused major delays in the envisaged nuclear rollout. This dissertation identifies the legal measures that Eskom as the licence holder and various government entities need to comply with to successfully roll out the nuclear component of the draft IRP 2018. It will describe the applicable legislation, processes and illustrative court cases. In so doing the work will provide guidance on the steps to follow to ensure that the nuclear rollout complies with the legal and policy framework of SA and gets delivered successfully and efficiently. The latest draft IRP 2018 which was published for public comments in the Government Gazette dramatically revises the forecast for SA’s energy demand downwards from a projection of 525 Terawatt hours (TWh) of power in 2050 to 430 TWh for the most optimistic ‘high’ scenario. This revision is the main reason the new IRP no longer calls for massive new coal plants and has relegated nuclear to specific scenarios instead of the ‘base case’. The carbon budget (IRP6) and carbon budget plus market-linked gas price (IRP7) scenarios commission nuclear capacity of 4200 megawatts (MW) and 5600 MW respectively for the period 2031-2040. IRP 6 and 7 have 6 per cent (6.3GW) and 7 per cent (7.35 GW) nuclear of 105 Gigawatt (GW) of installed capacity respectively, up from the 3 per cent (1830 MW) of Koeberg Nuclear Power Plant (Koeberg NPP). For the period 2041 – 2050, IRPs 6 and 7 have 6 per cent (7.56 GW) and 8 per cent (10.08 GW) nuclear of 126 GW of installed capacity respectively. The dissertation identifies the legal requirements and issues and makes recommendations on the steps to be followed to enable a legally sound nuclear rollout for SA.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2001. / Includes bibliographical references. / This study demonstrates the first successful implementation of a fission converter to produce a source of epithermal neutrons suitable for BNCT. The final design, construction and characterization of a new epithermal neutron beam is presented. A high intensity source with low contamination is obtained using a fission converter driven by thermal neutrons from the MIT research reactor. The facility is housed in the experimental hall and operates in parallel with other user applications. The fission converter is powered by 10 spent MITR-II fuel elements and employs resonance scattering filters with thermal neutron absorbers to tailor the neutron energy distribution. A lead shield attenuates photon contamination in the beam and lead collimators direct the neutron beam toward the patient. A horizontal beamline leads to the new medical room which is built with 1.1 m thick, high density concrete walls and is large enough to permit various treatment configurations. Ambient dose equivalent rates outside the shielded room are < I mrem/hr with the converter operating at full power and do not interfere with other experimental users and reactor operations. / (cont.) Beam delivery is controlled with three in-line shutters that allow unrestricted access to the medical room while the reactor is at full power. Patient irradiations are controlled by redundant programmable logic controllers that automatically close the beam shutters when the prescribed monitor counts have been accumulated. Measurements were performed on central axis to assess beam performance. An in-air epithermal neutron flux of 8.4 +/- 0.8 E+09 n/cm2s was obtained with concomitant fast neutron and photon absorbed dose rates of 3.9 +/- 0.5 and 11.8 +/- 0.8 cGy/min. Depth dose profiles measured in-phantom are in general agreement with those determined from Monte Carlo calculations and indicate that normal tissue tolerance can be reached in treatment times of less than 10 minutes. The in-beam fast neutron and photon contaminants account for less than 10% of the dose received by normal tissue surrounding the target volume, which approaches the clinical optimum. / by Kent J. Riley. / Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2001.

Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references (leaves 98-109). / The control of oxidative metabolism was studied using carbon-13 (13C) nuclear magnetic resonance (NMR) spectroscopy to determine the ratelimiting steps in 13C labeling of glutamate. 13C NMR spectra were acquired from isolated rabbit hearts perfused with either 2.5 mM [2- 13C] acetate or 2.5 mM [2- 13C] butyrate, and with or without KCl arrest. The tricarboxylic acid (TCA) cycle flux and the interconversion rate between (-ketoglutarate and glutamate were determined by least-square fitting of a kinetic model to NMR data. Rates were compared to flux through glutamate-oxaloacetate transaminase (GOT). Despite similar oxygen use, hearts oxidizing butyrate showed delayed incorporation of 13C label into glutamate and lower TCA cycle flux due to the influence of [beta]-oxidation: 8.0±0.2 [mu]moles/min/g dry weight with butyrate versus 10.5±0.4 with acetate at normal workload; 1.7±0.1 with butyrate versus 2.9±0.1 with acetate at potassium arrest (mean±SD). The interconversion rate between ca-ketoglutarate and glutamate ranged from 4.1±0.9 (butyrate+KC1) to 10.7±1.0 gmoles/min/g dry weight (acetate), at least 20-fold slower than the flux through GOT, and this proved to be the ratelimiting step in glutamate labeling. The results indicate that dynamic 13C NMR is sensitive not only to TCA cycle flux but also to metabolite transport rate across the mithochondrial membrane. To explore the effect of altered transport rates on the kinetics of glutamate labeling, metabolite exchange across the mitochondrial membrane was observed with 13C NMR spectroscopy in hearts oxidizing 2.5 mM [2- 13 C] butyrate at normal (no lactate) or high cytosolic redox state (2.5 mM lactate). High cytosolic redox state showed little effect on substrate utilization and TCA cycle activity. The TCA cycle flux was 9.7±0.5 [mu]moles/min/g dry weight with butyrate only and 10.2±0.3 with butyrate plus lactate. However, lactate induced a more than four-fold increase in the interconversion rate, from 3.1±0.2 gmoles/min/g dry weight to 14.3±2.0. These data indicate increased metabolite transport across the mitochondrial membrane due to stimulated malate-aspartate shuttle activity in response to elevated cytosolic redox state. / by Xin Yu. / Sc.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references (p. 149-151). / Emergency diesel generators are one of the most important contributors to the core damage failure rate of nuclear power plants. Current required testing and maintenance procedures are excessively strict and expensive without any real justification. Probabilistic risk assessment is used to propose a monitoring system and Technical Specification changes to reduce EDG unavailability without jeopardizing safety, and to ease the excessive deterministic requirements. The EDG fault tree is analyzed to identify the critical failure modes of the EDG, the failure of service water pumps, the failure of EDG building ventilation dampers, and the failure of the EDG "supercomponent," which includes the fuel oil, lubricating oil, cooling water, and starting air systems. We use data from the nuclear industry and the U.S. Navy to identify the most significant EDG supercomponent failure modes, including system fluid leakages, instrumentation & controls failures, electrical power output failures, and the fuel system governors. The monitoring system proposed includes instrumentation for twenty-one of the 121 basic events in the fault tree, for a total of 94.9% of EDG failure contributions. The failure modes identified with industry data are monitored, as are diesel engine mechanical failures currently assessed with teardown inspections. With a 50% reduction in these twenty-one basic event failure rates, the EDG system failure rate is reduced by 41.6%, from 0.097 per year to 0.059 per year. With this reduced failure rate, we propose to extend the EDG surveillance interval from one month to twelve months, to lengthen the running tests from one hour to twenty-four hours, and to eliminate the tear-down inspections conducted during refueling outages. To fully assess the benefits of these proposed changes, the monitoring system should be installed on an EDG on a trial basis. The work reported here demonstrates the feasible gains which can be realized, and proposes, a method for evaluating the efficacy of the system as realized through experimentation. / by Jeffrey D. Dulik. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references. / An "electron cyclotron resonance" plasma source, used for physical vapor deposition of copper into sub-micron features, was studied to determine whether parameters, such as gas atom density, electron density and temperature, surface bias, and copper ionization fraction at the deposition surface, influenced fill quality of the features. The results indicated that the fill quality was insensitive to all parameters except for the surface biasing conditions; however, with the use of an argon plasma, the bias was limited to less than ~- 40V due to the sputtering of the dielectric features by the argon ions (a phenomenon know as faceting). Switching to a copper evaporative system allowed for a pure copper plasma, enabling the use of greater (in magnitude) surface bias, ; I- 200V , before faceting by copper ions was observed. The fill quality of the features degraded with moderate bias (</= - 100V) but improved with bias > 150V . These results suggest that one formula for successful metallization is the use of an etch-resistant dielectric material in conjunction with large negative surface bias. / by Khashayar Shadman. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references (leaves 58-65). / Radiofrequency energy loss has been investigated for a resonant NMR surface coil between 20 MHz and 400 MHz. High-field NMR (> 64 MHz) is used increasingly for human imaging and spectroscopy to achieve improved SNR and spectral resolution. RF losses in coils designed using conventional lumped-element principles, however, often limit the practicality of high-field imaging. New design principles are required for the construction of efficient high-field RF coils. The RF energy losses investigated include RF coil losses and losses to a phantom load. These were studied using single-loop, resonant surface coils. Coil Q values, both unloaded and loaded, were measured and used to determine the coil radiation resistance, load resistance, B, field magnitude, and SNR. Radiation resistance is shown to increase like RR ~ f04. It is widely believed that load losses dominate all other losses in biomedical NMR. This study indicates that limiting radiation losses may improve loaded coil SNR at high frequencies. To this end, one may decrease the coil electrical length and/or apply transmission line principles in the construction of RF coils. Decreasing the coil electrical wavelength may be accomplished by decreasing the coil dimensions. Transmission line principles, which have been demonstrated for volume coils, improve performance by minimizing the coil radiation resistance. / by Mark D. Skubis. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references. / The Boron Neutron Capture Therapy (BNCT) treatment planning process of the Harvard/MIT team used for their clinical Phase I trials is very time consuming. If BNCT proves to be a successful treatment, this process must be made more efficient. Since the Monte Carlo treatment planning calculations were the most time consuming aspect of the treatment planning process, requiring more than thirty six hours for scoping calculations of three to five beams and final calculations for two beams, it was targeted for improvement. Three approaches were used to reduce the calculation times. A statistical uncertainty analysis was performed on doses rates and showed that a fewer number of particles could not be used and still meet uncertainty requirements in the region of interest. Unused features were removed and assumptions specific to the Harvard/MIT BNCT treatment planning calculations were hard wired into MCNP by Los Alamos personnel, resulting in a thirty percent decrease in runtimes. MCNP was also installed in parallel on the treatment planning computers, allowing a factor of improvement by roughly the number of computers linked together in parallel. After theses enhancements were made, the final executable, MCNPBNCT, was tested by comparing its calculated dose rates against the previously used executable, MCNPNEHD. Since the dose rates in close agreement, MCNPBNCT was adopted. The final runtime improvement to a single beam scoping run by linking the two 200MHz Pentium Pro computers was to reduce the wall clock runtime from 2 hours thirty minutes to fifty nine minutes. It is anticipated that the addition of ten 900 MHz CPUs will further reduce this calculation to three minutes, giving the medical physicist or radiation oncologist the freedom to use an iterative approach to try different radiation beam orientations to optimize treatment. Additional aspects of the treatment planning process were improved. The previously unrecognized phenomenon of peak dose movement during irradiation and its potential for overdosing the subject was identified. A method of predicting its occurrence was developed to prevent this from occurring. The calculated dose rate was also used to create dose volume histograms and volume averaged doses. These data suggest an alternative method for categorizing the subjects, rather than by peak tissue dose. / by John Timothy Goorley. / S.M.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references. / There is a need for high intensity and low contamination epithermal neutron beams, for boron neutron capture therapy research and for routine treatment if this becomes a successful modality for treating cancers. A fission converter based design for high performance epithermal neutron beam was developed at the Nuclear Reactor Laboratory of the Massachusetts Institute of Technology. This epithermal beam has the capability of delivering a treatment within minutes with negligible background contamination. This thesis deals with the engineering design of this facility. This fission converter based epithermal facility will be installed in the present thermal column and hohlraum of the MITR-II. The fission converter tank, which contains eleven MITR-II fuel elements, was designed with minimum front plate thickness to minimize neutron absorption. The converter tank structural analysis was performed analytically, and numerically with the finite element code ADINA. Three heat removal designs, natural convection, forced convection with bypass channel and simple forced convection, were considered to remove heat from eleven fuel elements in the fission converter tank. For all three designs, steady state and transient analyses were performed. The transient analysis includes loss of flow, loss of flow with shutter failure (converter scram) and loss of coolant. Most of these steady state and transient analyses were performed by both analytically and numerically. The results show that the fuel disruption will not occur during credible and incredible accident scenarios. Three shutters, cadmium shutter, water shutter and mechanical fast acting shutter were designed to control the beam at the patient position. The shutters were designed using the Monte Carlo radiation transport code MCNP. A medical irradiation room was designed for patient irradiation. The shielding computations for the medical room were also carried out with the MCNP. Fuel handling was investigated and proposed two options for refueling, which are similar to the MITR-II refueling. / by Balendra Sutharshan. / Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998. / Includes bibliographical references (leaves 115-121). / The technique of in vivo neutron activation analysis has been used for the determination of various elements in the human body. There are two methods of measuring nitrogen in vivo: (n,2n) method and prompt gamma neutron activation analysis (PGNAA). The first method utilizes the fast neutron reaction 14 N(n,2n) 13N and the second uses the thermal reaction 14N(n,y)1 N. Both methods are currently in use at several different facilities for evaluation of the nutritional status of surgical patients or metabolic study of normal human subjects. In order for the absolute determination of nitrogen, it is necessary to obtain the uniform sensitivity of detection in the subject. Experimental factors which influence the sensitivity are the activating neutron flux and the absolute detector efficiency. The distribution of the two factors in the human body is dependent on the spectral characteristics of the neutron source, the geometries of irradiation and counting systems and the size of the subject. In this thesis investigations of sensitivity and absorbed dose of the two nitrogen methods are made based on the results of Monte Carlo simulation. Two experimental facilities utilizing the (n,2n) method and the PGNAA method are simulated to assess the suitability and the feasibility of in vivo measurement of nitrogen. The potential of the use of an electrostatic tandem accelerator as a neutron source for nitrogen measurement is examined by simulating hypothetical experimental set-ups. Furthermore, those results obtained by the simulation are verified by performing accuracy measurements by the (n,2n) method. The counting system designed for human thigh measurement is described. The (n,2n) method delivers about half of the equivalent dose of the PGNAA method with same irradiation time. The simulation results showed 10 - 20 times higher sensitivity for the (n,2n) method than the PGNAA technique, depending on the patient position for the irradiation. The simulation results for the accelerator sources presented higher sensitivity than the 238Pu-Be radionuclide source conventionally used. / by Aiko Ishikawa. / S.M.