Browsing by Author "Tjiptono, TW"

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    Ageing management program of Kartini reactor for safe operation
    (International Atomic Energy Agency, 2007-11-05) Nitiswati, S; Syarip, S; Tjiptono, TW; Stathers, PA; Thorogood, KJ; Belvins, RJ
    This paper discusses the regular inspections of the Kartini reactor tank liner as part of the ageing management program. Kartini reactor is located in Yogyakarta, in Indonesia. The aim of the regular inspections is to assess the reactor tank condition as part of the ageing monitoring program to ensure safe operation of the reactor. The reactor was inspected utilizing a series of non-destructive inspection methods between 2001 and 2006. One of the inspection results was the detection of two swelling features seen on the bottom of the reactor tank. Kartini reactor has been in operation for 28 years and the observed swelling has been monitored over the past 5 years. The regular measurements and observations show that the swelling has stopped increasing in size and has now reached a stable size. After assessment and analysis of the cause of the swelling the reactor is considered to be in good condition and safe for future operation. © The Authors
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    Root cause analysis of swelling problem in Kartini Reactor
    (International Atomic Energy Agency, 2007-11-05) Syarip, S; Nitiswatia, S; Sardjono, Y; Sutondo, T; Tjiptono, TW; Stathers, PA; Belvins, R; Thorogood, KJ
    Root cause analysis (RCA) is applied for the swelling problem in the Kartini reactor. The RCA result shows that probable root cause of swelling are as follows: It is probable that the seal on the cover plate in the service pool has deteriorated and allowed water to enter both the thermal column and the space between the aluminium reactor pool liner and the concrete. The water will also saturate the concrete and has the potential to corrode the steel reinforcement close to the surface of the concrete. It is believed that water leakage from the service pool has entered the area behind the aluminium pool liner and has saturated the concrete. It is believed that carbon steel reinforcement close to the inner surface of the reactor block has corroded. The expanding corrosion product (rust) has the forced layer of concrete covering the steel reinforcement and subsequently pushing the aluminium pool liner inwards, causing the swelling. There are two issues: the mechanism for the creation of the swellings or bulges dominated by Iron corrosion, and the potential for corrosion of aluminium dominated by the pH of water in contact with the aluminium. As the evidence for this condition were: the apparent corrosion of steel reinforcement behind aluminium liner and formation of Ca(CO3) on outside of concrete reactor block indicating water saturation of the concrete block. The condition is advancing and will most probably result in a loss of pool liner integrity, this may or may not result in a loss of pool water due to the concrete backing behind the pool liner. Based on the above analysis, the remedial actions that can be considered are as follows: The pool liner would be patched with a welded panel that would allow the features we have observed to keep growing in a harmless way. It is expected that they will reach a finite size as the iron is consumed by corrosion. The area behind the pool liner would be dried out, this should limit further growth of the bulges by improving the corrosion conditions behind the pool liner. The bulk storage facility would be lined with stainless steel (the potential to use the thermal column could be preserved for future use). This would remove what is thought to be the root cause of the bulges and keep the reactor block dry. © The Authors