Some solutions to problems of compressing and containing tritium gas to 200 MPa at 700 K are discussed The principal emphasis is on commercial compressors and high-pressure equipment that can be modified easily by the researcher for safe use with tritium. Experience with metal belows and diaphragm compressors has been favorable. Selection of materials, fittings and gauges for high- pressure tritium work also is reviewed briefly.

The plateout distribution of gamma-emitting nuclides in the primary circuit of the Peach Bottom HTGR at end-of-life has been determined by in situ gamma scanning. The specific activity was mapped by scanning the accessible ducting at 12 locations with a Ge(Li) detector and by axially traversing 79 steam generator tubes with travelling CdTe detectors from the water side. Following destructive removal of trepan samples, a travelling intrinsic germanium detector was inserted sequentially into two vertical ducts and the plateout mapped along 6-m runs of ducting. Calibration measurements on mockups allowed reduction of the spectra to specific activity. The measured plateout profiles were in excellent agreement with those predicted with the PAD code. The dominant gamma emitters were Cs-137 and Cs-134; their relative distributions were similar. Little local structure to the plateout in the ducts was observed, only a gradual decrease in specific activity in the direction of coolant flow. In the steam generator, a significant entrance effect was observed in the superheater section; the activity was highest where the inlet jet impinged and lowest at the ends of the bundle despite the presence of a flow baffle. The effect damped out with penetration into the bundle, and the axial profile …

The effects of D. C. electric fields on high lying Rydberg and valence states in atomic uranium have been studied. Results of measurements of Stark shifts, lifetime lengthening via l-mixing, critical fields for ionization, barrier tunneling, and the appearance of zero-field parity forbidden transitions are presented for atomic uranium along with the observation of field induced autoionization of valence states. 3 figs. (GHT)