This document consists of information about the cooling systems of Hanford Production Reactors. It is the purpose of this letter, written May 8, 1961, to update recommendations of high-tank temperatures required to insure acceptable high-tank backup support. It does not appear practicable to relate the somewhat arbitrary standards of reference for backup support to process operating limits, i.e., reactor power levels, particularly as a mandatory requirement. For this reason, we have chosen at this time not to include these limits as a process standards` requirement. Considerable emphasis should be placed on insuring that the high-tank backup support be maintained in the maximum practical manner. Tables are attached showing high-tank temperature versus reactor power level relationships to satisfy the intent of our backup criteria and, through compliance, will insure that high-tank flow rates will be adequate during a reactor emergency following the loss of electrical power and steam.

The following data represents processing conditions used in fabricating prototypic (except for supports) natural and enriched NPR element assemblies and K-type I&E{sup 2} for the following production tests: ETR, 6{times}6 Loop; GEH-10, Nos. 52, 53, 54 and 55; KER Loops; PT-377; MTR Loop; GEH-4, Nos. 68, 69 and 70. The purpose in documenting the data is to provide a permanent record of processing conditions and dimensions which may be referred to for post irradiation analysis and possible future process work. Post irradiation results will be issued by the Fuels Development Operation, Hanford Laboratories Operation, and the test loop operating conditions will be issued by Process and Reactor Development Operation, Irradiation Processing Department, as outlined in the Production Test Procedure.

Tube-tube type fuel elements require support devices to maintain concentricity both between the element components and between element and process tube. A variety of support devices have been conceived. all require welding of a tab or other attachment device to the Zircaloy clad. Ultrasonic and resistance welding were evaluated for this application. Investigation showed ultrasonic welding to be not acceptable in its present state. Resistance welding proved satisfactory. This paper will briefly cover the work done in evaluating the two methods of attachment.