The objective of this test is to determine, through in-reactor testing, the resistance to corrosion of nickel plated fuel elements, plated by a chemical deposition technique. This program may eventually be composed of the following portions, the first of which is authorized by this test: (1) Irradiate ten columns of 0.5 mil chemically nickel-plated C-64 OIIN fuel elements having various heat treatments, each alternated with x-8001 control pieces. Two columns will be exposed to 400 MWD/T and eight to 800 NWD/T. (2) Should results from the above test be encouraging, separate authorization for the following tests may be requested: (a) Irradiate four columns of nickel-plated fuel and four of X-8001 clad fuel, both groups having purposely cocked pieces, until two ruptures are sustained in each group or until a factor of improvements of 400 is demonstrated at the 95% confidence level, unless the nickel-plated elements fail first. (b) Irradiate five columns of chemically nickel-plated C-64 clad OIIN fuel elements, alternating 0.2 mil and 0.5 mil plate, heat treated at 300{degrees}C for six hours. Two columns will be discharged at 400 MWD/T and three columns at 800 MWD/T exposure. (c) Irradiate approximately thirty columns of nickel-plated, C-64 alloy clad fuel elements …

A survey was made of sealing methods and their adaptability to the requirements of the plenum reflector seal on the HTGR reactor vessel. A leak rate through the seal of 43.8 pounds per hour of helium was established as an acceptable leak. Lap joints of steel to graphite or graphite to graphite with a 100 RMS surface finish met the required leak rate and two basic concepts of this type of seal are illustrated. (auth)

The daily check list, the startup procedure both for in-pool and in-air operation, and the normal shutdown procedure for the Tower Shielding Reactor-II are outlined. The sequence of events which leads to each annunciator warning and the automatic corrective action which is then initiated by the control circuits are described. (auth)

None

Artifacts were noticed in the microstructure of multimetallic beryllium samples that were polished on the Syntron vibratory polisher. The artifacts were at first erroneously attributed to diffusion of beryllium into the dissimilar metal. The real cause of the effect is thought to be caused by a galvanic corrosion which takes place during polishing. Small additions of sodium nitrate to the polishing slurry were found to eliminate the corrosion. (auth)

Progress is indicated on various research activities in the fields of exprrimental nuclear physics, reactor physics, and physics of nuclear safety. Separate abstracts were prepared for the 14 sections of the report. (For preceding period see HW-63576. For subsequent period see HW66215.) (W.D.M.)

Oxidation rates for U/sub 3/Si/sub 2/ in air were determined at 100, 200, and 315 deg C. Both as-cast and heat-treated material was considered, with no significant difference being observed. (C.J.G.)

In the past several years the use of neutron monitors for Pu concentration monitoring has been expanded in the Chemical Processing Department. Most of these monitors have been quite successful, and considerable effort is being made to improve the operation of both existing and future monitoring systems. One of the major improvements has been the development and use of a transistorized pre-amplifier or impedance matching circuits. This unit solves several problems associated with the use of boron trifluoride (BF3) neutron detectors in process monitoring; e.g., vacuum tube pre-amp failure because heat is not being conducted away.