The Expansion Joint Test are detailed in this report are part of the work accomplished under Design, Development and Research Contract DDR-111 between General Electric Company, Hanford Atomic Products Operation and Washington State University. The equipment and instrumentation used for the K-Downcomer tests were arranged to permit installation and testing of the expansion joints.

Interim results of analytical investigation of nuclear and thermal characteristics of SM-2 type fuel elements in SM-1, SM-lA, and PM-2Ae reactor cores are reported. Utilizing modified two-proup diffusion theory, predictions of power distribution and core and rod reactivity were performed. The calculations indicate that use of SM-2 fuel elemente in SM-1, SM-lA, and PM-2A is feasible from the nuclear standpoint. A steady state thermal analysis of each plant utilizing SM-2 elements was carried out. This analysis showed that the minimum departure from nuclear boiling ratios were considerably abovs the minimum value ftom the design criteria standpoint at both the operating and scram power levels. The investigation indicated that SM-2 elements can successfully be employed in SM-1, SM-lA, and PM-2A as replacement core elements. (auth)

Abstract; SM-1 Reactor Core I Rearranged and Spiked, and Core II with Special Components were analyzed under various off-design conditions to induce nucleate boiling. The steady state code, STDY-3, written for the thermal analysis of pressurized water cores, was employed for the analysis. The code performs a complete steady state parallel channel thermal analysis for both nominal and hot channels. Thermal characteristics of individual elements were investigated while changing the parameters of primary pressure or inlet temperature to introduce the phenomenon of nucleate boiling in the the core. Reduction of system pressures to 1000, 800, and 600 psia and increasing core inlet temperatures to 465 and 500 degree F were studied as the means to induce boiling in the core. This analysis indicates that SM-1 Core I Rearranged and Spiked can be safely operated at the reduced pressure of 910 psia without introducing extensive boiling in the core. SM-1 Core II with Special Components can be operated at 800 psia or at an inlet temperature of 500 degree F at 1200 psia.

Interest in neptunium recovery became active in early 1958. At this time neptunium chemistry was sketchy, the path of neptunium through the Purex Plant was not clearly defined nor were the effects of operating variables on the path. An intense research and development program carried out in Hanford Laboratories Operation, research and Engineering Operation (CPD), and Purex Operation led to the first recovery attempt in June 1958. Continuing efforts on flowsheet improvement resulted in further neptunium recovery from Purex. In April 1961 a routine neptunium isolation run was undertaken. During the course of this run approximately 75 per cent of the accumulated neptunium was lost to the high level waste storage tanks. It is the purpose of this report to document the facts surrounding this occurrence.

Plans for deactivation of the Sl-1 facility, which underwent a nuclear excursion on Jan. 3, 1961, are discussed, along with results of radiation surveys of the facility area The condition of the reactor is described iid detail. Plans for injecting a boric acid solution into the core are disclosed; subsequently, it was decided to leave the core dry and to decontaminate and disassemble the reactor. All involved equipment are described. (D.L.C.)