KPVP 2015 년도 연차학술대회(2015.11.19~2015.11.20) 요약논문 Copyright ⓒ 2015 KPVP

AREVA’s Filtered Containment Venting System and Other Technologies for Safety Improvement

† * ** Marina Welker , Norbert Losch and Axel Hill

1. Introduction 2.1.1 Tests and qualification Mitigation of severe accidents in nuclear power plants After an intensive internal full-scale test and qualification focuses on protection of the public, the operators and plant program, AREVA performed and met all national and structures/ systems. The containment pressure might increase international qualification programs, including third party and threaten the containment integrity. The goal of the Filtered testing. Containment Venting System is to allow a controlled reduction International experts recommend testing and qualification of the containment pressure through venting cycles while in programs for containment venting devices under severe various filtration steps trapping the radioactive isotopes, thus accident conditions. AREVA performed extensive tests as per drastically reducing off-site impact. these recommendations. These programs include tests with Apart from pressure reduction in the containment, also accident typical aerosols, Cs, I, hard-to-retain micro aerosols, monitoring systems are required to provide the status of the gaseous iodine as well as tests concerning re-entrainment plant and its equipment / systems. effects in the frame of the US ACE (Advanced Containment In addition, the rooms designated for prolonged occupancy Experiments) Filter Test Program and JAVA Program. AREVA throughout the duration of accidents have to be protected from verified the aerosol and gaseous iodine retention for the whole activity which could leak outside the containment. range of the relevant pressure operation. 2. AREVA’s Filtered Containment Venting (FCVS) 2.1.2 Overview of AREVA’s FCVS product family [3],[4],[5] Due to particular technical requirements of customers and 2.1 Technology overview safety authorities AREVA developed some specific technical AREVA offers the standard FCVS as a combined double- FCVS features. All these developments are part of the AREVA staged process. It uses the advantages of a high-speed venturi FCVS Product Family. scrubber technology (wet stage) combined with an especially Table 1. AREVA’s FCVS Product Family designed highly efficient deep-bed fibre filter (dry stage). All FCVS FCVS FCVS I-CATCH components are installed in a pressure vessel and operate under Plus Standard Basic sliding pressure conditions. This results in a very compact Filtration High speed High speed High speed – system design. stage 1 venturi venturi venturi This unique combination of dry and wet stages enables to scrubber scrubber scrubber benefit from the technical advantages of both solutions. Filtration Metal fiber Metal fiber Demister – The AREVA standard FCVS can be extended with an stage 2 filter filter optional third filtration stage which is targeted to meet higher Filtration Molecular – – Passive requirements regarding organic iodine retention. It uses the stage 3 sieve superheating advantage of the sliding pressure operation mode of the first and (I-CATCH) and second stage to create passive superheating for the downstream molecular third sorbent stage (I-CATCH process). sieve stage This third stage could also be installed as an upgrade to an (I-CATCH) already installed FCVS, e.g., in case of increasing requirements Decontamination factors concerning organic iodine retention. Fine > 10.000 > 10.000 > 100 The combination of the above named three stages allows a aerosols (>99,99%) (>99,99%) (>99%) modular design to meet the constraints regarding possible Large > 100.000 > 100.000 > 1.000 locations / compartments in terms of the installation of the aerosols (>99,9999%) (>99,9999%) (>99,9%) system. Elemental > 1000 > 200 > 200 >10-1000 Iodine (>99,9%) (>99,5%) (>99,5%) (>90-99.9%) † Marina Welker (AREVA GmbH) Organic > 10 - 10001 ~ 5 ~ 5 > 10-1000 E-mail : [email protected] Iodine (>90-99.9%) (~80%) (~80%) (>90-99.9%) TEL : +49 (0) 9131 900-95606 FAX : +49 (0) 9131 900-94008 1 * Norbert Losch (AREVA GmbH ) The organic iodine decontamination factor is subject to customization. ** Axel Hill (AREVA GmbH) KPVP 2015 년도 연차학술대회(2015.11.19~2015.11.20) 요약논문 Copyright ⓒ 2015 KPVP

2.2 AREVA’s FCVS experience worldwide containment to the atmosphere of the plant), containment Since 1987, AREVA has designed, licensed and delivered leakages or containment bypass to adjacent buildings. more than 80 FCVS for different reactor types worldwide: PWR To ensure that the workforce’s exposure to radiation doses (including VVER), BWR and PHWR (CANDU). While the does not exceed specified limits (according to OECD detailed system designs may differ with the reactor types, the recommendation, doses within the control room should be kept unique AREVA design has shown to be sufficiently flexible for below 100 mSv over a 7-day period), special measures need to the respective required adaptation. Moreover, AREVA addresses be taken both during and after a severe accident to prevent customer-specific requirements by partnering, scope split activity from entering the control rooms. flexibility (engineering, hardware delivery, turnkey) and AREVA has developed a Control Room Air Filtration localized manufacturing. AREVA has broad experience with the System (CRAFT) to protect control rooms and emergency stringent application of different national codes and standards. response centers – or other rooms designated for prolonged 2.2.1 AREVA’s licensing experience with FCVS occupancy throughout the duration of accidents – from Based on AREVA’s experience with safety authorities radioactive releases. CRAFT filters airborne radioactive around the world AREVA has gained a unique understanding of pollutants (e.g., iodine, aerosols) and poisonous gases and also the important key points regarding licensing aspects. By now, retains noble gases by means of dynamic adsorption. AREVA has gained broad and long-term experience with FCVS CRAFT has no limitation of operation time. It is designed licensing worldwide. Quick and qualified support of the to operate during the complete accident progression and is customer and regular technical exchange are essential during the suitable even in case of multiple venting scenarios. licensing process. AREVA’s technical expertise [2] allows to 4. Conclusion support customers in an optimal way and to participate in AREVA has broad experience in severe accident analysis discussions with safety authorities. and mitigation. Thus, AREVA can offer the full range of 2.2.2 JAVA facility guidelines, instrumentation and mitigation measures for Regarding AREVA’s FCVS all main parameters and management of severe accidents in NPPs. With this AREVA dependencies have been verified by large-scale tests. Moreover, helps NPP operators to upgrade their plants to meet stricter AREVA’s JAVA facility as backup is available in AREVA’s requirements that supervisory authorities have imposed or may Technical Center in Karlstein/ Germany to perform additional impose. tests in case new authority questions should arise. Detailed information regarding AREVA’s entire portfolio of 3. Other solutions for plant safety severe accident management solutions can be found in 3.1 HERMETIS – Containment atmosphere AREVA’s Safety Alliance Catalogue [1] and on our website. monitoring [6],[7] This portfolio represents AREVA’s worldwide contribution to Monitoring of the containment atmosphere, e.g., the level of safety improvements of NPPs. hydrogen and other combustible gases, is required in case of References severe accident in order to timely provide the baseline decisions 1. AREVA Safety Alliance, Products, Services and Solutions, November 2012, AREVA 2012 for mitigating actions, e.g., filtered venting. AREVA 2. The European PASSAM Project on severe accident source HERMETIS Monitoring System is proven to operate under core term mitigation, https://gforge.irsn.fr/gf/project/passam/ melt accident conditions. 3. Containment Venting System Technologies for PWR´s and The system works with in-situ micro sampling based on BWR´s to mitigate Severe Accidents; B.Eckardt, N.Losch; AREVA NP GmbH; PBNC March, 2012, Busan, South capillary pipe technology. Thus, only fully metallic components Korea are placed in harsh environment, and the entire measuring 4. OECD/NEA/CSNI Status Report on Filtered Containment equipment is installed outside of the containment and easily Venting, NEA/CSNI/R(2014)7, 02-Jul-2014 accessible for operators. The system measures the concentration 5. AREVA’s Filtered Containment Venting System (FCVS) - Basic Design, Performance and Verification Test of FCVS of, e.g., hydrogen, oxygen, CO (and CO2, if needed) and steam. for BWRs; N.Losch, S.Buhlmann, Ch.Hutterer, Ch.Stiepani; With the information of HERMETIS the combustion regime AREVA GmbH; In joint collaboration with: F.Totsuka, prevailing inside containment can be reliable assessed by the T.Tsukahara, Hitachi-GE Nuclear Energy Ltd.; K.Hosomi, crisis team. Furthermore the CO concentration measurement Toshiba Corporation, SPES 2014, Japan 6. New Multi–Functional Containment Atmospheric indicates whether the plant is in an in-vessel or ex-vessel Monitoring System Technology HERMETIS for Severe situation. Accident Management. Test Results and Implementation, 3.2 CRAFT - Control room accident filtration [8] A.Hill, B.Eckardt, J.Koch, AREVA NP GmbH, TOP Safe In case of a severe accident in NPPs radioactive releases Helsinki 2012 7. Multifunctional Containment Atmosphere Monitoring, may leak into control rooms – such as main and emergency A.Hill, AREVA GmbH, NUSSA, Beijing 2012 control rooms. These radioactivity releases could be caused by, 8. Noble Gas Control Room Accident Filtration System for e.g., discharge of activity, (e.g. of noble gases, from the Severe Accident Conditions N-CRAFT, A.Hill, Ch.Stiepani, M.Drechsler, ICMST, Kobe 2014