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This report describes the development activities for the fabrication of the Thermal Expansion Difference irradiation temperature monitor (TED) at the Oarai Engineering Center (OEC)/PNC. TED is used for various irradiation tests in the experimental fast reactor JOYO. TED is the most accurate off-line temperature monitor used for irradiation examination. The TED is composed of a metallic sphere lid and either a stainless steel or nickel alloy container. Once the container is filled with sodium, the metallic sphere lid is sealed by using a resistance weld. This capsule is then loaded into a reactor. Once a TED is loaded into the JOYO reactor, the sodium inside the metallic container increases as a result of thermal expansion. The TED identifies the peak irradiation temperature of the reactor based on a formula correlating temperature to increment values. This formula is established specifically for the particular TED being used during a calibration process performed when the TED is fabricated. Initially the TED was developed by Argonne National Laboratory (ANL) in the United States, and was imported by PNC for use in the JOYO reactor. In 1992 PNC decided to fabricate TED domestically in order to ensure the stability of future supplies. Based on technical information provided by ANL, PNC began fabrication of a TED on an experimental basis. In addition, PNC endeavored to make the domestically produced TED more efficient. This involved improving the techniques used in the sodium filling and the metallic sphere welding processes. These quality control efforts led to PNC's development of processes enabling the capsules to be filled with sodium to nearly 100%. As a result, the accuracy of the temperature dispersion in the out-pile calibration test was improved from 10 $^{circ}$ C to 5 $^{circ}$ . In 1996 the new domestically fabricated TED was attached to a JOYO irradiation rig. In March of 1997, irradiation of the rig was started on the 30th duty cycle operation, .

JAEA Reports

Field test of the PNC mobile investigation system

*; *; Nakano, Katsushi

PNC TN7410 98-001, 37 Pages, 1998/02

PNC-TN7410-98-001.pdf:2.39MB

Power Reactor and Nuclear Fuel Development Corporation (PNC) has been developing groundwater research instruments in order to characterize hydraulic and geochemical environments in the deep underground. As part of this development programme, a support system was developed in 1996 to conduct groundwater investigations efficiently. This system, called the PNC Mobile Investigation System, consists of 5 units: a data acquisition and analysis unit, a maintenance unit, a hoisting unit, a cable drum for hydraulic tests (Type I), and a cable drum for groundwater sampling (Type II). The system is the following features: (1) Groundwater investigation is possible without a drill machine and rig. (2) Long term investigation is possible without housing facilities and utilities. (3) Maintenance of instruments is possible in the field. (4) Control units, such as the computer, are well protected from the external environment. (5) Groundwater analysis is possible in the field. (6)Recovery of instruments stuck in the borehole is possible using the emergency hoisting unit. The first field test of this system was performed in February and March, 1997. Through this test, it was confirmed that the system had met its performance design when combined with a proper hydraulic test instrument. Much useful information for future improvements to the system was also obtained.

JAEA Reports