Evatech 2003
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DRAFT Version 1 5 May 2003 Draft version of a hypothetical accident scenario for the EVATECH seminar on May 12 -14 Finnish workshop on clean-up actions for residential areas after a nuclear accident: Accident scenario and background information FOR TRAINING PURPOSE ONLY EVATECH project under EC’s 5th framework programme --------------------------------------------- Michael Ammann STUK - Radiation and Nuclear Safety Authority Research and Environmental Surveillance Laippatie 4, FIN-00880 Helsinki P.O. Box 14, FIN-00881 Helsinki E-Mail: [email protected] Tel: ++ 358 9 75988/488 Fax: ++ 358 9 75988/498 --------------------------------------------- 1 Contents Contents........................................................................................................................... 2 Introduction ..................................................................................................................... 3 Accident scenario .......................................................................................................... 3 Accident site and affected region...........................................................................................................................3 Events of the accident day.......................................................................................................................................5 State of affairs a week later.....................................................................................................................................8 Received and future doses ...............................................................................................................................9 Consequence assessment and interventions ...............................................................................................11 Zone 0: Loviisa close to the site...................................................................................................................13 Zone 1: Loviisa, Gislom, and partly Liljendal and Lapinjärvi................................................................14 Zone 2: Liljendal, Lapinjärvi, Pernaja, Ruotsinpyhtää.............................................................................16 Zone 3: Pernaja, Liljendal, Lapinjärvi, Myrskylä, Artjärvi, Orimattila, Ruotsinpyhtää.....................17 Zone 4: Rest of the province Uusimaa ........................................................................................................18 Workshop.......................................................................................................................19 Intervention strategies............................................................................................................................................19 References.....................................................................................................................21 Appendix ........................................................................................................................22 Clean-up techniques and their applicability .......................................................................................................22 Roads and pavement.......................................................................................................................................23 Roofs and walls ...............................................................................................................................................23 Lawn..................................................................................................................................................................24 Trees and bushes .............................................................................................................................................24 Soil ....................................................................................................................................................................24 Selected attributes...................................................................................................................................................25 Averted collective dose..................................................................................................................................25 Averted dose per caput...................................................................................................................................25 Collective dose to clean-up workers............................................................................................................25 Costs..................................................................................................................................................................25 Waste disposal.........................................................................................................................................................25 Models for dose assessment, cost and resource quantification.......................................................................26 Model output............................................................................................................................................................28 2 Introduction International organisations have been advocating for many years that radiation protection authorities should involve stakeholders (different braches of industry, trade, service, and also the public) in the national planning for protective actions in case of a nuclear accident. Facilitated workshops provide a valuable instrument for this involvement. Within the EVATECH project of the 5th framework programme of the European Commission facilitated workshops are planned in a number of European countries to learn about the practical needs of decision makers and stakeholders. The intention is to improve decision support systems and in particular to shape further their evaluation subsystems. The workshops concentrate on later phase countermeasures for residential areas (EVATECH WP4, Description of work). A case study of a hypothetical accident at a national nuclear power plant provides the basis for the workshop, which is arranged seven days after the accident. A variety of stakeholders is invited to broadly evaluate the options that are available a week after the accident to protect the urban population from undue exposure and to clean up urban areas. The underlying accident scenario is presented here. Accident scenario An objective of the EVATECH project is to learn from the decisions made in the different participating countries. Since it would be helpful to directly compare the advised intervention strategies, each country uses the same accident scenario and it is strived to have a comparable population distribution in the vicinity of the accident site. In this way the release and dispersion of radioactive material are the same in all participating countries; but the boundary conditions also mean for many countries that the NPP has to be fictitious both in respect to type and other characteristics and in respect to location. In Finland, the site of the Loviisa NPP is chosen, but the reactor is in accordance to the guidelines for the workshops and not the actual one. Accident site and affected region The assumed NPP at Loviisa is a PWR with a large, dry steel containment and around 2000 MW(t) power. It is located on a sparsely populated island about 10 km southeast of the city Loviisa. Loviisa with a population of 7,600 is a small town at the southern coast of Finland, about 90 km to the east of Helsinki. Helsinki and surroundings on the other hand are the most densely populated regions in Finland. Other important population centers of the region are Porvoo, Lahti, and Kotka (Fig. 1 and Tab. 1). 3 Fig. 1 Municipalities and population distribution of the region (above) and of Loviisa and surroundings (below) Tab. 1 Population of the municipalities in the region Municipality Population Muncipality Population Anjalankoski 18459 Lammi 5886 Artjärvi 1696 Lapinjärvi 3219 Askola 4259 Liljendal 1534 Elimäki 8626 Loviisa 8105 Espoo 177100 Luumäki 5565 Hamina 10012 Myrskylä 2033 Hausjärvi 8027 Mäntsälä 15191 Helsinki 487876 Nastola 15073 Hollola 20074 Nurmijärvi 28946 Hyvinkää 40047 Orimattila 14168 4 Hämeenkoski 2331 Pernaja 3734 Hämeenlinna 43444 Pornainen 3471 Iitti 7700 Porvoo 45500 Janakkala 15339 Pukkila 1828 Järvenpää 32839 Pyhtää 5434 Kauniainen 8140 Riihimäki 25297 Kerava 28184 Ruotsinpyhtää 3275 Kotka 55731 Sipoo 14978 Kouvola 31875 Tuusula 28050 Kuusankoski 21417 Valkeala 11291 Kärkölä 5304 Vantaa 157156 Lahti 92525 Vehkalahti 12296 Fig. 2 Population centers of the region. In Finland about 80 percent of the population lives in such urbanized areas. Events of the accident day Various decisions are made at different points in time. The narration of the events is kept in the present time in order to facilitate arbitrary entry points into the flow of events. Wed May 14 00:00 The Radiation and Nuclear Safety Authority (STUK) receives a notification from the operator of the Loviisa nuclear power plant reporting that a fire broke out at 00:00 in the electrical cabinet of reactor 1 and caused the shutdown of the reactor. 5 01:00 The effects of the fire and an independent failure of the emergency core cooling system prevent core cooling. The containment is isolated. Site emergency is declared. 02:00 The 5-km zone is being evacuated (Fig. 3). Fig. 3 Five-kilometre zone and population distribution 03:30 The core is