[3G03-05] Monitoring and Inspection

[3G03] Verification of Alternative Dew Point Hygrometer for CV-LRT in Monju

Short-Term and Long-Term Verification for Capacitance Type Dew Point Hygrometer

*Masakazu Hatori¹, Fumiyasu Ono¹, Hisashi Abe², Hiroshi Kitano², Nobuo Hashiri³, Taisuke Inuzuka³, Yusuke Chiba¹, Shoichi ICHIKAWA¹, Takanori Kobayashi¹, Ryoichi Uekura¹ (1. Japan Atomic Energy Agency, 2. Advanced Industrial Science and Technology, 3. Mitsubishi Heavy Industries)

Keywords:Monju, CV-LRT, Dew Point Hygrometer, Capacitance Type, Lithium-Chloride Type, High-Precision-Mirror-Surface Type, Maintenance Periods

In order to reduce the influence on a plant schedule of Monju by the maintenance of dew point hygrometers, JAEA Agency examined a capacitance type dew point hygrometer as an alternative dew point hygrometer for a lithium-chloride type dew point hygrometer which had been used at the containment vessel leak rate test in Monju. As a result of comparing a capacitance type dew point hygrometer with a lithium-chloride type dew point hygrometer at the CV-LRT (Atmosphere: nitrogen, testing time: 24 hours), there was no significant difference between a capacitance type dew point hygrometer and a lithium-chloride type dew point hygrometer. As a result of comparing a capacitance dew point hygrometer with a high-precision-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, testing time: 24 months), it was confirmed that a capacitance type dew point hygrometer satisfied the instrument specification (the precision synthesized a detector and a converter: ±2.04 degree C) required by the CV-LRT. There are no other cases where atmosphere measurement has been carried out for a long time by existing measuring instruments.