Case-by-case reviews of selective world experience with severe local faults, particularly fuel failure and fuel degradation, are reviewed for two sodium-cooled thermal reactors, several LMFBRs, and LMFBR-fuels experiments. The review summarizes fuel-failure frequency and illustrates the results of the most damaging LMFBR local-fault experiences of the last 20 years beginning with BR-5 and including DFR, BOR-60, BR2's MFBS-and Mol-loops experiments, Fermi, KNK, Rapsodie, EBR-II, and TREAT-D2. Local-fault accommodation is demonstrated and a need to more thoroughly investigate delayed-neutron and gaseous-fission-product signals is highlighted in view of uranate formation, observed blockages, and slow fuel-element failure-propagation.

Electron cyclotron resonance heating (ECRH) is necessary for forming and sustaining the thermal barrier in the plasma fan region at each end of the large MFTF-B tandem mirror. 1600 kW of gyrotron-generated power at 28 GHz and 56 GHz is planned to meet this requirement. Cold plasma ray-tracing calculations have been started in order to maximize the antenna-to-plasma coupling efficiency during startup of the experiment. However, a hot plasma formulation is needed at later times. In the cold plasma regime, the X-wave is found to be efficiently absorbed, but the O-wave absorption is still quite inefficient for most of the rays considered thus far.

Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface.

Mechanisms leading to loss of alpha particles from non-axisymmetric tandem mirrors are considered. Stochastic diffusion due to bounce-drift resonances, which can cause rapid radial losses of high-energy alpha particles, can be suppressed by imposing a 20% rise in axisymmetric fields before the quadrupole transition sections. Alpha particles should then be well-confined until thermal energies when they enter the resonant plateau require. A fast code for computation of drift behavior in reactors is described. Sample calculations are presented for resonant particles in a proposed coil set for the Tandem Mirror Next Step.

A fluid-structure-interaction algorithm has been developed and incorporated into the two-dimensional code PELE-IC. This code combines an Eulerian incompressible fluid algorithm with a Lagrangian finite element shell algorithm and incorporates the treatment of complex free surfaces. The fluid structure and coupling algorithms have been verified by the calculation of solved problems from the literature and from air and steam blowdown experiments. The code has been used to calculate loads and structural response from air blowdown and the oscillatory condensation of steam bubbles in water suppression pools typical of boiling water reactors. The techniques developed have been extended to three dimensions and implemented in the computer code PELE-3D.

Experimental programs at Argonne ZGS are reviewed with emphasis on experiments using polarized beams.

Guidelines for decontamination and decommissioning were presented and discussed at this workshop. Statements considered were: (1) the dose limits will be those currently available as federal guidance from the President or as regulation; (2) the actual cleanup will be conducted to provide final levels as low as can be reasonably achieved; (3) DOE will retain effective direction of the work during its progress; (4) a precleanup survey, including both radiological measurements and thorough documentation of the previous use or uses of the property will be made to assist in planning; (5) the use of single radionuclide to serve as an indicator for a group of radionuclides shall be proven to be valid for each area; (6) all operations during the initial survey, cleanup, and final certification of the area will be thoroughly documented; (7) the final judgment on the suitability of the area for its final use will be made from a final certification survey along with consideration of the information collected during the cleanup; and (8) instrumentation, sampling methods and analytical methods shall be properly calibrated, shall have appropriate sensitivity and shall be capable of giving results in a time meaningful to the cleanup operations or certification survey. (DC)

Time-series analysis techniques are applied to nuclear reactor thermocouple data to investigate coolant temperatures measured within the fueled test assembly. The coolant temperature distribution within a fuel assembly affects the length of time a fuel assembly may be operated in a power reactor and, therefore, is an important economic consideration in the design of reactor fuel systems. Frequency-domain signal conditioning techniques were used to reveal the smoothly varying thermocouple signals from the noisy digital data. Examination of the cross-correlation function for thermocouple pairs suggested an alternate surging and ebbing of coolant flow within certain zones of the fuel assembly. These zones corresponded to thermocouples which experienced higher or lower than predicted coolant temperatures. This time series analysis contributed greatly toward the understanding of fuel assembly thermal hydraulics.

This article discusses the specificity of plant defences.