Reactor Enclosure Tank

Besides the reactor tank, an elaborate stainless steel system was pro- vided for handling the heavy water. The entire experimental arrangement occupied a two-level concrete cell enclosure so that the heavy water could be raised from a reservoir tank on the lower level into the reactor tank on the upper level by means of dried compressed air. The heavy water could be dropped quickly, if necessary, to stop a chain reaction. Side holes in the reactor tank made possible the insertion of foils to be activated by the neutron flux for flux distribution measurements on a horizontal line through the reactor, and vertical flux measurements were conveniently made in an empty fuel tube hole. Typical horizontal and vertical flux distributions are given in Figs. Al.C and D. 

Calibration of metering pumps to be tested by collecting the discharge in separate tanks. This is to ensure correct feeding of raw materials to process reactors. The instmments can indicate correct readings when the probes are installed in flowing fluids and not at idle pockets of vessels or ducts. The probes should be corrosion-resistant or installed in suitable enclosures (stainless steel/ceramic/ Teflon—coated thermowell instead of stainless steel/ceramic/Teflon coated thermowell). Strainers shall be provided in sampling lines to prevent deposits of salts and ash on the probes especially those for pH measurements and concentration analysers. 

With a second amendment to the core unloading license (7/12a), no-contamination-measurements of components in the turbine hall and in the adjacent feedwater tank building and the disassembly of the steam-feedwater-cycle mufflers on the roof of the reactor hall were permitted. Only the waste water discharge station in the supervised area of the turbine hall continued to be subject to measurement after having achieved the state of safe enclosure. 

---