The 12th International Conference on Environmental ... - Events

Abstracts Session 18
After the evaluation of the experience made during the transport and the radiological measurements and samplings taken from
the RPV unit 1, the strategy for the dismantling of the reactors was changed. <strong>The</strong> reactor pressure vessels of the units 1 to 4 and
the reactor internals of the units 3 and 4 should be removed as complete parts and stored as shielded large components in the ISN.
In summer 2005 EWN applied for the new strategy at the responsible licensing authority and in August 2007 this license was granted.
In November 2007 the reactor pressure vessels of the units 1 and 2 were transported into the ISN. <strong>The</strong> transport of the reactor
pressure vessels and the internals from units 3 and 4 is planned in the period from March till September 2009.
<strong>The</strong>se transports of the reactor pressure vessels and internals show that the dismantling of the reactors with dismantling and
interim storage of large components could not only be an alternative for cutting but could also be favored from the economical and
radiological point of view.
2) TECHNOLOGY DEVELOPMENT FOR DECOMMISSIONING IN FUGEN AND CURRENT STATUS - 16108
Koichi Kitamura, Japan Atomic Energy Agency (Japan);Kazuya Sano, Yasuyuki Nakamura,
Akira Matsushima, Masahiro Ishiyama, Hidehiko Matsuo, Masashi Tezuka, Takahiro
Haneda,Japan Atomic Energy Agency (Japan)Reginald Coomans, Tecnubel (Belgium)
<strong>The</strong> decommissioning program of proto-type Advanced <strong>The</strong>rmal Reactor (ATR) FUGEN has started in 2008 as first decommissioning
of the commercial-scale water reactor. It consists of four periods, considering the transportation of spent fuels and the
radioactive decrease of highly activated materials. It is expected that the whole program of decommissioning will be completed
until 2028.
Now, the decommissioning is under the first period, spent fuels and heavy water has been carrying out from FUGEN, and a
part of the turbine system with relatively low radioactive contamination has been dismantled.
FUGEN has a complicated core structure consisting 224 fuel channels with pressure tubes and calandria tank, etc. and used
heavy water as moderator, unlike other light water reactor (LWR). <strong>The</strong> materials of the core structure were highly activated due to
a long term operation, tritium and C-14 were generated, and the facilities were contaminated by them. Thus, it is important to study
the dismantling technology of the reactor core and the decontamination technology, considering characteristics of FUGEN such as
core structure and radioactive inventory in advance.
In this presentation, the contents of the decommissioning program and its current status such as dismantling work of a part of
the turbine system, the studying situation of dismantling technology of reactor core using Abrasive Water Jet (AWJ) which is a candidate
of cutting technologies, the examination of tritium decontamination in heavy water system, the study of decontamination
technology for C-14 will be presented mainly.
3) SEEKING THE OPTIMUM SOLUTION FOR REACTOR DECOMMISSIONING WASTE – 16391
Lisa Hughes, NDA (UK)
<strong>The</strong> current baseline plan for reactor decommissioning waste in the UK is to package the waste in to approved containers pending
geological disposal. <strong>The</strong> waste arising from reactor decommissioning currently accounts for 35% by volume of the total waste
destined for geological disposal in the UK. <strong>The</strong> majority of this waste (approximately 30% by volume of the UK total) is graphite
from reactor cores.
<strong>The</strong> NDA Strategy published in March 2006 and the current NDA business plan both made a commitment to explore management
and treatment options for reactor graphite waste. Since this commitment NDA has carried out a work programme on graphite
options. CoRWM’s recommendation on reactor decommissioning wastes in 2006 and Governments response also recognised the
need for alternative solutions for all wastes arising from reactor decommissioning.
Since the publication of these reports NDA has initiated the Reactor Decommissioning Wastes project. This project will examine
the hazard reduction and potential cost benefit of options of alternative management of reactor decommissioning waste. This
will focus on Magnox reactors in the NDA estate, but in considering the position with regard to the large waste graphite liability,
will also take account of the eventual decommissioning of graphite moderated AGR reactors owned by British Energy.
This paper will provide an overview of the project, the proposed approach, options under consideration and timescales for
development.
4) MODELLING OF RADIATION FIELDS AND ESTIMATION OF DOSES DURING
DISMANTLING OF RBMK-1500 REACTOR EMERGENCY CORE COOLING SYSTEM - 16247
Povilas Poskas, Audrius Simonis, Lithuanian Energy Institute(Lithuania)
<strong>The</strong>re is only one nuclear power plant in Lithuania Ignalina NPP. <strong>The</strong> INPP operated two similar units with installed capacity
of 1500 MW (each). RBMK-1500 were commissioned in 12/1983 and 08/1987, and the original design lifetime was projected out
to 2010 and 2015 respectively. But the first Unit of Ignalina NPP was shutdown December 31, 2004, and second Unit will be closed
down in 2009.
In relation with this, implementation of new technologies for treatment and conditioning of radioactive waste, construction of
the interim dry storage facility for spent nuclear fuel and preparation of the licensing documents for decommissioning of the Unit
1, and some other projects were implemented or are under implementation at Ignalina NPP. Implementation of dismantling activities
requires detailed knowledge of the radiological situation at the Unit 1. General Radiological Characterization Program for
Ignalina NPP Unit 1 based on NUREG-1575 was prepared in 2005-2006 and approved by Regulatory Bodies.
In 2008 development of the dismantling projects at Ignalina NPP Unit 1 has been started. Dismantling project of the emergency
core cooling system (Building 117/1) is the first project in this field. Based on the radiological surveys data, detailed modeling of
the radiation fields has been performed using VISIPLAN 3D ALARA Planning tool computer program (SCK CEN, Belgium). So,
in this paper detailed information on radiation fields modelling, proposals for optimization of the radiation doses to the personnel,
and emergency core cooling system equipment dismantling is presented.
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