Development of the residual sodium quantification method for a fuel assembly of SFRs

Kudo, Hideyuki*; Inuzuka, Taisuke*; Hara, Masahide*; Kato, Atsushi; Nagai, Keiichi; Ide, Akihiro*

Journal of Nuclear Science and Technology, 57(1), p.9 - 23, 2020/01

https://doi.org/10.1080/00223131.2019.1651229

In sodium-cooled fast reactors (SFRs), it is necessary to remove the sodium remaining on spent fuel assemblies (FAs) before storing them in a spent fuel water pool (SFP) in order to minimize plant operating loads. A next-generation SFR in Japan has adopted an advanced dry cleaning process which consists of the following steps: argon gas blowing to remove the metallic residual sodium on the FA, moist argon gas blowing to deactivate the residual sodium, and direct storage in the SFP. This process increases economic competitiveness and reduces waste products. In this R&D work, performance of the dry cleaning process has been investigated. This paper describes experimental and analytical work focusing on the amount of residual sodium remaining on FA components, for instance the handling head, the wrapper tube, the upper shielding, and the entrance nozzle which was conducted after investigation of residual sodium on fuel pin bundles as a part of series study of the cleaning process.

Verification of alternative dew point hygrometer for CV-LRT in MONJU; Short- and long-term verification for capacitance-type dew point hygrometer (Translated document)

Ichikawa, Shoichi; Chiba, Yusuke; Ono, Fumiyasu; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*

JAEA-Research 2017-001, 40 Pages, 2017/03

JAEA-Research-2017-001.pdf:5.19MB

In order to reduce the influence on a plant schedule of the MONJU by the maintenance of dew point hygrometers, The JAEA 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 CV-LRT in the 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 weren't 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-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, Testing time: 24 months), the JAEA confirmed that a capacitance type dew point hygrometer satisfied the instrument specification (2.04C) required by the JEAC4203-2008.

Verification test of alternative dew point detector for CV-LRT in Monju

Chiba, Yusuke; Ichikawa, Shoichi; Ono, Shimpei; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Abe, Hisashi*; Kitano, Hiroshi*

no journal, , 

The lithium chloride-type dew point detector was used for reactor containment vessel the entire leak rate test (CV-LRT) in fast-breeder reactor Monju (Monju) which needs the maintenance every three months. But when the plant process is considered, it's desirable for the maintenance periods beyond 12 months. Thereupon the capacitance-type dew point detector made in VAISALA Corporation was nominated as the alternative lithium chloride-type dew point detector in Monju. The lithium chloride-type dew point detector, when it's adopted, for, to have to be satisfied a request of the regulations, it's necessary to estimate the performance of the lithium chloride-type dew point detector. In the condition of the CV-LRT, the dew point data were measured by the capacitance-type dew point detector and the lithium chloride-type dew point detector for 24 hours. These data were compared and the performance of the capacitance-type dew point detector was estimated. Furthermore, the dew point data of Monju under the atmosphere ware continuously measured by the capacitance-type dew point detector and the mirror surface-type dew point detector for 2 years. These data were compared and the performance of the capacitance-type dew point detector was estimated. As a result, the capacitance-type dew point detector was confirmed that had the instrument precision that JEAC4203-2008 required.

Verification of alternative dew point hygrometer for CV-LRT in MONJU; Short and long-term verification for capacitance type dew point hygrometer

Hatori, Masakazu; Ichikawa, Shoichi; Chiba, Yusuke; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*; Ono, Fumiyasu

no journal, , 

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 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.