Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: Unusual occurrences during the whole operation of BN-250 NPP

Andropenkov, S. (Mangyshlak Atomic Energy Complex (Kazakhstan))

Abstract

Unusual occurrences during the whole operation BN-350 NPP. 1 .Oil ingress in high pressure receiver for the not reveled reason, 12.05. 1994. 2Increase of water radioactivity of circulating water supply system due to heat exchanger leak of spent fuel assembly washing out system, 17.09.1993. 3.Lack of passableness of sodium drain header of primary circuit reveled during inspection on scheduled preventative maintenance, 28.11.1996. 4.Destruction of the blow-off line of MCP-6 due to corrosion damage of the pipeline while unit was being operated at rated power, 23.04.1993. 5.Lack of passableness of blow-down pipeline connecting reactor gas cover with gas-type pressurizer while unit was being operated at rated power, 17.11.1994. 6.Sodium ingress in blow-down pipeline of loop-5 intermediate heat exchanger while loop-5 was being fed of sodium during scheduled preventative maintenance, 27.06,1994. 7.Resistance deterioration of electroheating zones of loop-4 due to heat exchanger leak and water ingress in air-pipeline of primary circuit boxes recirculating air system, 02.05.1997. 8.Resistance deterioration of electroheating zones of sodium drain header of secondary circuit was sopped in the water for the extinguishing the fire of blowing ventilation oil-strainer, 23.12.1994. 9.Sodium ingress in gas-type pressurizer through pipeline of primary sodium cleanup system and blow-down pipeline of failed MCP-2 while primary sodium cleanup system was being connected to the primary circuit, 17.08.1976. As a rule, the main reactor systems are scrutinized more carefully than the auxiliary reactor systems and the order actions are existed for eliminating and mitigating of –consequences of main reactor system fails. Therefore the auxiliary reactor system fails may impact on the main reactor systems through places of its contact in significant measure. The influence of auxiliary reactor system fails on main reactor systems and its possible consequences for behavior of the main reactor systems have been analyzed on the basis of the above-mentioned occurrences. Significance of the above-mentioned occurrences for nuclear safety BN-350 NPP have been analyzed too.

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key words: auxiliary systems; bn-350 reactor; corrosion; engineered safety systems; failures; heat exchangers; primary coolant circuits; reactor cooling systems; remedial action; sodium; water supply
Reference:
Technical committee meeting on unusual occurrences during LMFR operation. Vienna (Austria) 9-13 Nov 1998
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--1180, pp:169-179