Miyuki Akiba

374. 燃料集合体信頼性実証試験―BWR燃料集合体熱水力試験

Nuclear Power Engineering Corporation (NUPEC) has conducted a proving test for thermal-hydraulic performance of BWR fuel (high-burnup 8×8, 9×9) assemblies entrusted by the Ministry of Economy, Trade and Industry (NUPECTH-B Project). The high-burnup 8×8 fuel (average fuel assembly discharge burnup: about 39.5GWd/t), has been utilized from 1991. And the 9×9 fuel (average fuel assembly discharge burnup: about 45GWd/t), has started to be used since 1999. There are two types (A-type and B-type) of fuel design in 9×9 fuel assembly. Using an electrically heated test assembly which simulated a BWR fuel bundle on full scale, flow induced vibration,

BWR 9×9 Fuel Assembly Thermal-Hydraulic Tests: 1 — New Formula for Post Boiling Transition Heat Transfer Correlation and Rewet Correlation

Nuclear Power Engineering Corporation (NUPEC) conducted thermal-hydraulic projects for verification of thermal-hydraulic design reliability for BWR high-burnup 8 x 8 and 9 x 9 fuel assemblies, entrusted by the Ministry of Economy, Trade and Industry (METI). As a part of the NUPEC thermal-hydraulic projects, post boiling transition (post-BT) tests by the use of full-scale test assemblies simulating 9 x 9 fuel were carried out to evaluate BWR fuel integrity. Two kinds of post-BT tests, the steady-state post-BT test and transient post-BT test were performed, and the test results were applied to development of new heat transfer and re-wet correlations for the estimation of fuel rod surface temperature. (authors)

Experimental Study on Improvement of Inlet Orifice in BWR Core

The purpose of this study is to develop the core inlet orifice whose drag coefficient changes according to flow rate without drive parts. We improved on the conventional orifice by giving it a novel shape; the edge of the improved orifice is half-oval in shape. This improved orifice was tested under high-pressure and high-temperature (about 7.2 MPa and 570 K) simulated ABWR conditions. Test results showed that the drag coefficient of the orifice with the novel shape changed according to flow rate. It was found from these test results that drag coefficient was constant and high under ABWR natural circulation conditions and decreased by about 20% under ABWR rated power conditions. In addition, a task for the future was educed.