Abstract: The primary coolant of the SM-1 (APPR-1) was analyzed for short-lived and fission product activities. Manganese-56 was found to be the predominant non-fission product nuclide contributing to the short lived activity. Fission products were found in the coolant. It is concluded these fission products originate from a defects in the cladding and from surface contamination of the fuel elements.

Abstract; This technical report describes the changes in the SM-1 incurred by the experiment, Core Temperature and Flow Instrumentation (Task XIV), and evaluates the possible hazard involved in these changes. Temperature and flow measurements will be taken on a Task XIV instrumented stationary fuel element, instrumented control rod fuel element and other selected points in the SM-1 core to provide data on the core steady state and transient performance. The hazards evaluation consists of a nuclear evaluation, thermal and hydraulic analysis, description of tests to be performed, and discussion of containment integrity and maximum accident considerations.

Abstract: This technical report describes the changes incurred in the SM-1 by the insertion of the SM-1 Core II and special components. The special components consist of impact specimens, a boron gradient rod, SM-2 elements, a PM-1-M element, and high burnup SM-1 Core I elements. The change in hazards, due to operation of SM-1 with Core II and the special components is evaluated. The analysis indicates there is no change in hazards.

Abstract: This technical report summarizes the results of research and development tasks performed during Phase I of this contract and presents recommendations for future development work. Work is reported in the areas of plant assembly and relocation, housings and footings, waste heat dissipation, instrumentation, refueling systems, waste disposal, shielding, core nuclear thermal and hydraulic studies, gaseous waste processing (BWR), and critical experiments on a 5 x 5 array of Type 3 fuel elements.

Abstract: This technical report contains a comprehensive analysis of the nuclear characteristics of the SM-1 Core I. Comparison of analytical and experimental results for neutron ages and core reactivities of a variety of cases investigated shows that the MUFT III with P-1 slowing down approximation gives the best results. At startup the core reactivity and rod bank worth under various operating conditions are investigated and compared to experiment. Core lifetime was calculated to be 16.8 MWYR compared to 16.4 MWYR experimental. The temperature coefficient has been calculated and compared to experiment as function of burnup. In Appendix A, flux distribution, temperature coefficient, effective delayed neutron fraction and core life are analyzed by Dr. R. L. Murray by one and two group modified theory series expansion calculations.

Abstract: A detailed description of the PM-2A reactor, primary system and instrumentation is presented. A general description of the secondary system and plant arrangement at Camp Century, Greenland is included. The results of the startup physics, shielding, thermal and hydraulics and radiochemistry test are presented. the analysis performed on the shielding and thermal and hydraulic tests is included. The shielding problem at startup and the shielding modification made to the plant are described along with the radiation measurements made in these areas.

Abstract: Neutron flux and gamma radiation measurements through the SM-1 primary shield were made at the startup of Core II in June 1961. They extend previous measurements (APAE-35) both vertically and horizontally in the primary shield and in the rod drive pit. Dose rate measurements on spent fuel elements under water are also reported.

Abstract; The heat exchanger and steam generator for the U.S. Atomic Energy Commission Sodium Components Project will be constructed entirely of type 316 stainless steel. Because of the susceptibility of this alloy to stress corrosion cracking, it is proposed to clad all areas of the steam generator with Inconel where the stainless steel will be exposed to water and steam. This report includes a discussion of the work by numerous investigators that justify the selection of Inconel for this service. A discussion of Inconel type welding alloys is also included.

Abstract: This report presents metallurgical .analyses and corrosion tests conducted to determine :causes of failure of two SM- 1 reactor vessel studs due to fracture in the threaded areas, after 23 months' operation (March 1959). Conclusions of corrosion tests are: (1) failure of the studs was caused by stress corrosion cracking, (2) contributing factors to failure of the studs were improper control of heat treatment of the studs and absence of treatment for stress relief after thread grinding operation.

Abstract: An element by element reactivity check for SM-1 Core II fuel elements and control rod absorber sections was performed and the burnable nuclear poison loading in the SM-1 Core II stationary fuel elements was established. An approach to criticality of the SM-1 Core II was performed by the inverse multiplication method and the critical rod bank position obtained as a function of fuel loading up to the full SM-1 Core II loading. Maximum and minimum core reactivity measurements were obtained by selective loading of stationary fuel elements and the total "excess K" for the core established. Power distribution measurements in the region of the core-reflector interface and the fuel-absorber interface in the control rod assemblies were performed. The effectiveness of europium flux suppressors in the top of control rod fuel elements and the power peaking in stationary elements adjacent to water gaps in control rod assemblies were measured. Survey measurements established the worth of spiking cold clean SM-1 cores with SM-2 elements, and of water holes in the SM-1 core which might be utilized as flux traps for materials irradiation.

Abstract: This technical report contains a summary of experimental and analytical work performed on cold clean SM-1 Core II with special components and PM-2A Core I each with thermal shield and vessel mockups. The purpose of this work was to define the neutron intensity and spectra to which the pressure vessels are subjected in order to assess the effect of irradiation on the vessel lifetimes. The radial distributions of the energy dependent neutron flux per unit power in the core and vessel mockups are presented. The uncertainties associated with the measurements are also given. In addition to graphical and tabular presentations of the test results, discussions are provided on the experimental techniques and theory. A review of the analytical models is provided in addition to the calculational results. A special analytical study of the the PM-2A Core I power distribution and absolute power level determination is given. A comparison of the experimental and analytical results is made and conclusions and recommendations presented.

Abstract: In the March-April 1962 shutdown of SM-1 Core II, the SM-28 element will be re-inserted in SM-1 Core II and an SM-1 Core I element will be removed. An SM-1 Core II europium absorber will be replaced by a Ag-Cd-In absorber, and surveillance specimens will be inserted above the core support structure. Analysis of these changes concludes that re-insertion of the SM-2B stationary element and insertion of surveillance specimens do not affect hazards potential previously defined for SM-1. Replacement of the europium absorber by the Ag-Cd-In absorber will have negligible effect on reactivity control worth of the rod. The absorber meat section is encapsulated to prevent exposure of silver alloy to the primary coolant; postulated release of silver due to a cladding defect, after 2 years irradiation in SM-1, would not cause a hazard such as to restrict access to the vapor container. Possibility of steam formation in the air gap between the absorber core and cladding, causing a cladding failure, is remote. Deformation of the absorber section sufficient to cause the rod to stick, would not impair the ability of the other rods to shut down the reactor safely.

Abstract: This technical report covers the zero power experiments performed on PM-2A Core II at the Alco Critical Facility. PM-2A Core II is the first replacement core for a portable pressurized reactor at Camp Century, Greenland. Core II is the same as Core I with the exception that Core II has an increased burnable poison (B-10) content. The zero power experiment consisted of fuel element uniformity test; core assembly test, development of an on-site loading procedure and an analysis of experimental data. Physical characteristics determined include distribution of fuel and B-10 in the fuel plates, minimum critical mass, control rod bank calibration, and integral rod worth. The report concludes with an analysis of the experimental data including estimated uniform and non-uniform burnup rates.