Ageing Management in TR-2 and Related Legislation and Experience in TAEK

Transcription

1 Ageing Management in TR-2 and Related Legislation and Experience in TAEK Yasin ÇETİN Technical Meeting on Research Reactor Ageing Management, Refurbishment and Modernization, and Test Research and Training Reactors conference 2015 Brewster, Massachusetts, United States of America 5-9 October

2 Outline Turkish Atomic Energy Authority (TAEK) Structure of TAEK Nuclear Facilities in Turkey Current NPP sites National programme Research Reactor TR-2 Reactor Main Features Ageing Management in TR-2 2

3 Turkish Atomic Energy Authority In 1956, General Secretariat of Atomic Energy Commission was established in Ankara Turkey is a founder member of IAEA. In 1982, the Commission was restructured as Turkish Atomic Energy Authority affiliated to Prime Ministry 3

4 Structures of TAEK 4

5 Nuclear Facilities in Turkey TRIGA Mark II Research Reactor in Istanbul Technical University (1979) TR-2 Research Reactor in Çekmece Nuclear Research and Training Center (1962) In Turkey, nuclear technology has been used in various areas such as medicine, research, industry etc. many years. There is no nuclear power plant in operation or decommissioned. 5

6 Current NPP Sites in Turkey Akkuyu Site is the only licensed site for NPP s (in 1976) Studies started to determine the other new candidate site(s) for NPP in 2004 Site survey phase was completed in 2006 Sinop Site was selected as the second NPP site (but not licensed, yet) According to the Decree, there are three licensing steps for NPPs, Site License Construction License Operating License 6

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8 National Programme Akkuyu Nuclear Power Plant (ANS) Inter Governmental Agreement with Russia 4x1200 MWe VVER BOO model, including decommissioning Project will be subject to all applicable laws, regulations and codes in Turkey. All necessary licenses, permits and approvals from related governmental organizations shall be obtained by the Project Company 8

9 National Programme Sinop Nuclear Power Plant (SNS) Inter Governmental Agreement with Japan 4x1100 MWe Atmea-1 Enhancing the regulatory capabilities of TAEK Developing further regulations Developing human resources 9

10 TR-2 RESEARCH REACTOR 10

11 Reactor Main Features French design (Granoble), Constructed by Belgonucliare and General Atomic (electronics-instrumentation) ID: TR-2 Research Reactor Location: Cekmece Nuclear Research and Training Center, Istanbul Type : 5 MW, Open Pool, Fuel : 23 plates, LEU (MTR) 11

12 HISTORY of TR-2 RR 1981 First criticality of TR Operated at 3MW between (limited power operation) Operated at 5MW between (nominal power operation) Utilization: Radioisotope production (99Mo, 192Ir) Neutron Activation Analysis Training 1995 Reactor was shutdown to re-assess the seismic safety Operated at 300kW (limited by RB because of seismic safety) 2005 Feasibility studies for power increase (9 MW) 2009 Spent fuel elements transferred to USA (HEU Fuels) Fresh fuels deposited in storage room (LEU Fuels) 2013 Reinforcement of reactor building was completed in June 2016 We are planning to resume operation of TR-2 step by step 12

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15 Modifications Done when Installing TR-2 Pool The TR-1 reactor pool had ceramic lining. The old lining was causing water leakage from the pool. The pool surface was coated with stainless steel. Primary coolant loop Aluminium pipes in the primary cooling circuit of the TR-1 reactor were embedded in concrete under the pool. Pipes were investigated for leakage after disassembly of the TR-1. Several tests were conducted. After these tests, usage of the old aluminium pipes was cancelled. Stainless steel pipes were installed for the TR-1 and TR-2 reactors. Demineralization system Pipes of the TR-1 demineralization system were embedded in pool walls and the bottom part of the pool. The old demineralization system was intended for use by TR-2. However, investigations after disassembly of TR-1 showed that usage of the old system for TR-2 was impossible. A new system was implemented with stainless steel pipes. Reactor hall Airlock doors were added in order to decrease air leakage from the reactor building. The TR-1 reactor facility, however, was not constructed as an airtight volume. There were numerous factors that affected the sealing of building. Many systems were also changed or modified for these reasons. 15

16 Ageing Management Programme Ageing management in TR-2 is performed in three stages. 1) Ageing prevention It consists of actions taken in order to minimize corrosion ph and conductivity values of pool water are investigated on a daily basis for this reason. Regeneration of ion exchangers is performed due to these water values. 2) Ageing investigations Routine investigations in systems are used for inspecting ageing, as sometimes ageing can be seen during unsatisfied operations. In these cases, aged SSCs are found as the reason for unsatisfactory operation. 3) Ageing handling Repair is the first option in ageing handling. It has a cost advantage but can cause obsolescence in SSCs. If repair is not possible for aged SSCs, modernization is undertaken. 16

17 AGEING MANAGEMENT BASED ON SSCs The building The reactor was shut down because of concern for the seismic safety of the building. A refurbishment project for the building was finished in

18 Secondary coolant loop A huge amount of rust was seen at the filters. Three years of shutdown caused an air inlet to the pipes. The existence of air in secondary coolant pipes increased the corrosion rate by oxidation. These pipes were used until the previous shutdown in Pipes were replaced in Modernizations in secondary coolant loop Pipes were connected to new cooling towers 18

19 There are six cooling towers in the secondary coolant loop. These cooling towers were replaced with newer versions. Two new cooling towers were installed but have not yet been connected to the system. New pumps of secondary cooling circuit 19

20 Control rods The nickel coating of the control rods contains small amounts of Co impurity. This causes 60Co contamination of the pool water. Since the reactor was not in continuous operation after1995, the contamination level was not so high. Replacement of control rods is being considered for future operations. Drive mechanisms were unloaded for malfunction inspection. Drive motors consequently must be changed. Electromagnets were investigated. Huge amounts of rust were seen on the stainless steel surface of the electromagnets. This rust flowed through the pipes that connect the electromagnets to the drive mechanisms. Rust at magnets 20

21 Heat exchanger Stainless steel plates of the heat exchanger were damaged during routine maintenance and then replaced with titanium plates. Stainless steel plates of heat exchanger were replaced with Ti plates 21

22 Air conditioning system The air conditioning system was changed. Demineralization system The recirculation pump and some of the pipes were changed. Also, there is corrosion at the welds of stainless steel water softeners. Electric system Some modifications were done in the electric system. Connectors at the TK3 electric panel were changed, but the whole system needs refurbishment. I&C system There have been malfunctions in some relays in the safety logic of the I&C system, and the fission chamber need to be changed. Mechanical problems in recorders have also arisen in recent years, necessitating replacement by digital recorders. 22

23 Thank you for your attention 23