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This report has the following sections: Summary; Civilian Power Reactors; Applied and Reactor Physics; Reactor Fuels and Materials; Engineering Development; Plutonium Recycle Program; Advanced Systems; and Nuclear Safety.

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Insertion of target materials into a reactor displaces fuel. The remaining fuel must have higher enrichment to maintain reactivity and must operate at higher power density, or higher specific power, to maintain total reactor power. A specific power increase of about 20 percent has been demonstrated power. A specific power increase of about 20 percent has been demonstrated in the U-233 program and in preliminary coproduct irradiations in the N Reactor. Some extension above this is probably feasible with present fuels. However, substantial increase, such as doubling the specific power, may require a change in fuel element design configuration, in fuel core alloy, and in materials used for fuel cladding. In addition, optimum utilization of the N-Reactor recirculating cooling system will require thorough study and perhaps some limited development work. Increasing specific power to improve reactor flexibility with minimum modification of the reactor is especially attractive for the K and N Reactors. It is a possible, though more difficult, alternative to reactor modernization at the small reactors, but it forgoes operating savings and introduces difficult reactor safeguards problems.

As the military needs for plutonium decline, the Commission`s production-oriented reactor complex should develop and demonstrate pure non-defense operating modes to serve non-defense needs. The alternative is production reactor shutdowns coupled with needless expense in producing necessary products elsewhere or doing without them. Although the use of fully enriched fuel (partial or complete loadings) for the Richland production reactors was once practiced, renewed study and research to reestablish practical incentives, demonstrate technical feasibility (including reactor safety), and firm up product capability must be undertaken. It is unquestionably true that fully-enriched uranium can be utilized as fuel for the Hanford reactors. It is the purpose of this mission to develop the conditions under which this may be accomplished safely and productively, to determine the necessary plant modifications required to achieve this processing capability, to disclose the inherent plant limitations to such processing, and to evaluate the incentives for operating on fully enriched uranium fuel. The scope of this study will include: physics behavior of highly enriched fuels (prompt kinetic effects, total reflectivity effects, control system worths, and transient reactivity effects); fuel material studies; reactor effects (moderator and zirconium tube temperatures); and critical mass considerations in fuel handling. A separate, but coordinated, …

The Nuclear Safety Mission consists of a broad, integrated program of experimental and analytical studies designed to permit more accurate assessment of the consequences of accidents at Hanford nuclear facilities. Information obtained will assist in the design of facilities to further mitigate the consequences of accidents involving the release of radioactive materials from the Hanford nuclear reactors and chemical processing facilities. The Safety Mission consists of seven programs described briefly below and more fully in the contractor summary sections. These seven programs, named 13RLa through 13RLg, involve studies of the effects of a loss of coolant accident on fuel element temperature and fission product release, mitigation of noble gas release, meteorological studies at the N Reactor site for evacuation planning, soil retention characteristics and ground water flow patterns, mitigation techniques for plutonium spread in the case of fire, and building response to seismic events.

The plutonium production reactors operated by Douglas United Nuclear, Inc., use treated Columbia River water as coolant on a once-through basis. Thus, radionuclides formed largely from the activation of river salts are released to the river. In addition to the radionuclides, heat and other chemicals are also added to the river by the reactor effluent. These discharges give rise to a program which includes three separate and distinct areas of study. The first involves devising practicable methods of reducing the amount of radioactivity released. The second addresses the mechanisms by which the radionuclide releases could result in radiation exposure to people. The third area of study concerns determining the effects of reactor effluent on the quality of Columbia River water. Both the heat and the chemicals added by the effluent are being investigated in the third study area.

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Selected masonry structures in Mercury, Nevada, were inspected for cracking before and after certain nuclear detonations and during periods of no significant nuclear activity. Detonations gave peak particle velocities whose magnitudes approached those experienced in Mississippi during the Salmon event. Findings include evidence that peak particle velocities of 0. 1 to 0. 3 cm/sec caused more cracking than normal; however, cracks at these low levels of motion are not more severe than those occurring naturally.

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