TELEVISUAL INSPECTION OF CLEANLINESS IN SECONDARY SIDE OF STEAM GENERATOR
ZHOU SHOUKANG;DING XUNSHEN(Research Institute of Nuclear Power Operation)
For U-type tube steam generator(UTSG),the deposit will be piled on the low velocityarea of tubesheet,tube bundle and support plates in the period of operation,For example,on theupper surface of tubesheet,if the deposit piled up over given depth,the secondary water and tubewould separate in the piled region, causing the tube wall temperature increase,and acceleratingthe IGSCC of tube. If this deposit comprises a large amount of granular iron,then,it would leadto denting of tube end, and the lcose foreign object on the tubesheet would strike the tube andcause the tube plugging. The deposit is the hidden region of pollutant, and the concentration ef- fect will create the corrosion situation in secondary side of steam generator. So, it is very neces-sary to inspect the cleanliness of SG.The paper introduces the technique of cleanliness inspection with the VP3 1TV apparatus. The steam generator cleanliness inspection of GNP unit 1 and 2,after installation、 major tran-sients and commercial operation,shows that the 1TV technique not only provides the cleanlinesscondition of tubesheet,and removes the loose foreign object, but also provides the basis for thedetermination of lancing procedure,confirms the result of lancing,and gets the cleanliness con-clusion according to the appropriate qualified standard.
【CateGory Index】： TL353.13