Experimental investigation of quenching of a single exposed heated channel of 220 MWe IPHWR

• Published in: Nuclear engineering and design Vol. 382; p. 111397
• Main Authors: Dutt, Nitesh, Kumar Sahoo, Pradeep, Gokhale, Onkar S., Mukhopadhyay, Deb
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2021; Elsevier BV
• Subjects: Accidents; Boiling points; Decay; Exposure; Fire fighting; Flooding; Fuels; Heat exchangers; Heavy water; Injection; LCDA; LOCA; Low temperature; Mitigation; Nuclear fuels; Nuclear safety; PHWR; Quenching; SCDA; Suspended debris; Water injection; Suspended debris; LOCA; SCDA; PHWR; LCDA; Quenching
• ISSN: 0029-5493; 1872-759X
• DOI: 10.1016/j.nucengdes.2021.111397

•After quenching CT temperature remains below boiling point of water.•PT cools indirectly through cooling of CT.•Fuel pin simulators cool indirectly through cooling of PT. Postulated Beyond Design Basis Events without operator interventions may lead to moderator boil-off in Calandria of Pressurized Heavy Water Reactor (PHWR). The boil-off of moderator results to slow uncovey of fuel channels that leads to formation of suspended debris. An experimental setup is designed and fabricated to study the quenching behavior of a 220 MWe PHWR specific exposed fuel channel at 1–1.25% decay power level through flooding. The experiment simulates In-Calandria Fire Fighting Water injection as a part of Severe Accident management Guideline. During quenching, temperature of exposed calandria tube of fuel channel comes below boiling point of water. Cooling of exposed calandria tube indirectly cools the pressure tube and fuel pins, which attains steady state after a long time. In all case studies, the maximum temperature drop is observed at the bottom of pressure tube and found to be 187.5 °C and 192 °C for 1% and 1.25 % of decay power respectively. Fuel pins near the bottom of the PT attains the maximum temperature drop of 98.7 °C and 114.2 °C at 1% and 1.25 % decay heat levels respectively. Attaining low temperature of calandria tube is an important aspect in safety as it indicates mitigation of progression of Severe Core Damage Accident (SCDA). The experiments establish success of in-Calandria injection under Severe Accident Management Guidelines (SAMG) as designed by the utility.