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Factual information on radiation effects needs to be communicated in an understandable and timely manner to individuals in affected areas in order to enhance their understanding of protection strategies, alleviate their concerns and support their own protection initiatives.
Arrangements at the national and local level need to be put in place to share information in an understandable manner with the public who may be affected by accidents with radiological consequences. The arrangements need to allow for person to person dialogue, so that individuals can seek clarifications and express their concerns. These arrangements will require the concerted efforts of the relevant authorities, experts and professionals in supporting and advising the affected individuals and communities. Sharing information is important when conveying decisions to protect these individuals, including the support of their own initiatives.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 4 - Radiological Consequences
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV4-Web.pdf#page=179 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
During any emergency phase, the focus has to be on protecting people. Doses to the biota cannot be controlled and could be potentially significant on an individual basis. Knowledge of the impacts of radiation exposure on non-human biota needs to be strengthened by improving the assessment methodology and understanding of radiation induced effects on biota populations and ecosystems. Following a large release of radionuclides to the environment, an integrated perspective needs to be adopted to ensure sustainability of agriculture, forestry, fishery and tourism and of the use of natural resources.
It may be difficult to substantially reduce doses to non-human biota because of the impracticability of introducing countermeasures. Impact assessments for plants and animals in the aftermath of accidents such as that at the Fukushima Daiichi NPP require consideration of numerous potential stressors — radiation exposure being one of many. Consideration also needs to be given to the potential for the buildup and accumulation of long lived radionuclides in the environment and how this might affect plants and animals over multiple generations.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 4 - Radiological Consequences
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV4-Web.pdf#page=199 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
It is necessary to prepare in advance for post-accident recovery in situations that require the remediation of large areas, for example, in the event of a major nuclear or radiological accident.
Remediation preparedness would include planning, prior to any accident, for the implementation of generic remediation policies and the establishment of criteria for residual doses and contamination levels. Generic remediation plans must be readily adaptable to specific situations.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=67 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Further international guidance is needed on effective implementation of the radiation protection principles of justification and optimization in existing exposure situations.
This could include methodologies for assistance in the selection of case specific remediation action levels defined in terms of residual doses or derived quantities as well as procedures for a periodic review of action levels adopted in the early post-accident period to take account of changing radiological conditions. It could also include guidance on appropriate decontamination and remediation techniques. The guidance needs to address technical and scientific issues in addition to socially relevant factors and could promote the development of a coherent, transparent and collectively accepted decision making process.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=67 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
In choosing the reference level to guide the overall remediation strategy following a nuclear accident, it must be clearly understood by the government, the regulator and the affected public that this level is a long term target (often based on equity and ethical considerations),
whereas short term remediation targets must be realistic and economically defensible, based on sound optimization processes. The challenge is to achieve understanding among the affected public of the short term goals that are most beneficial socially. The choice of the additional dose of 1 mSv/y as a long term objective in post-accident recovery is ethically defensible on equity grounds, but will often be inappropriate for use as a short term target on grounds of feasibility and optimized social benefit.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=67 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Large scale radiation mapping created from aerial or systematic ground monitoring has value in identifying major areas requiring remediation planning.
However, the detailed remediation strategies depend on a more specific evaluation of local radiological conditions supported by area specific monitoring.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=67 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Remediation strategies need to be developed on a case by case basis and need to be flexible to enable adjustment to the situation as it develops.
They must take into account: • The doses received by the most exposed groups of the population. • Natural decay of the radionuclides that comprise the contamination, as well as anticipated natural weathering processes. These processes should be taken into account in determining the remediation strategy, including the timescale over which, in the absence of active remediation activities, these factors will reduce doses to acceptable levels. • The scale of remediation efforts and site specific factors, such as the effectiveness of dose reduction and the doses received by workers. • The amount of contaminated material generated. • The various resource constraints (e.g. financial resources, storage and disposal facilities, logistics and qualified human resources).
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=67 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
As part of the remediation strategy, the implementation of rigorous testing and controls on foods is necessary to prevent or minimize ingestion doses.
The systematic implementation of rigorous testing of and controls on food after the accident demonstrated that ingestion doses can be kept at low levels. To establish confidence in locally produced food, local monitoring stations were set up to allow people in affected areas to bring food to be measured. This control of ingestion doses simplified the recovery by allowing remediation to focus on techniques that reduce external doses.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=67 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Information from pilot projects for testing the effectiveness and feasibility of remediation measures plays an important role in the planning of remediation strategies.
The pilot projects provide training and experience in site specific decontamination and facilitate the development of guidelines for carrying out decontamination activities and procedures for ensuring worker safety. The involvement of stakeholders helps promote understanding and acceptance of remedial actions.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=67 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Decontamination in residential areas and public facilities is an effective way to reduce doses to the public for gamma emitting radionuclides.
This applies especially to situations where internal exposure is not a major component of the dose received by the population due to the implementation of restrictions on the production, sale and distribution of agricultural products.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=68 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
The dose assessment approaches used in the decision making for existing exposure situations must be regularly re-evaluated at different stages of the remediation process.
In general, the models need to be sufficiently conservative to be acceptable to all parties involved; at the same time, they need to be sufficiently realistic to allow appropriate optimization of protection from remediation.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=68 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Data must be obtained from environmental and individual monitoring and characterization to provide necessary inputs to dose assessment models.
Use of these data is essential for enhancing the reliability of dose assessments and predictions and for allowing remediation strategies to be tailored to site specific conditions.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=68 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Following an accident, a strategic plan for maintaining long term stable conditions and for the decommissioning of accident damaged facilities is essential for on-site recovery. The plan needs to be flexible and readily adaptable to changing conditions and new information.
Such a plan serves as guidance for managing and coordinating the activities at the site. It is important that it provides a prioritized approach for completing the critical activities, including identification of key interactions between activities, criteria for decision making and the role of R&D in defining alternatives for future activities. A different regulatory approach for post-accident situations is necessary to allow the required flexibility in response to encountering unforeseen issues.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=104 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Once on-site stabilization has been achieved, it is important that the long term reliability of SSCs essential for safety is assured and maintained. Alternatives to the pre-accident SSCs (including backups) may be needed for many functions. In the long term, installation of new systems may be more effective than attempts to repair existing systems.
A combination of traditional and innovative approaches may be needed to ensure reliability of SSCs. In some instances, they need to be tailored to the unique conditions, including the potential for future damage from natural hazards, in which the SSCs are performing within damaged facilities.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=104 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Cooling fuel within a damaged nuclear reactor may require the use of large volumes of water that will entail subsequent treatment, conditioning and storage.
Managing and characterizing cooling water before, during and following its processing will consume resources (money, human resources, time). The selection of treatment systems depends on the type of radionuclides and their concentrations and on other constituents that may be present in the water. The situation is more complex than during normal operations owing to the presence, for example, of boron, sea water minerals, particulate matter and microorganisms. Waste water management at the Fukushima Daiichi NPP is a challenging problem owing to the volume of water requiring processing, storage and/or discharge. Although international guidance exists for discharges during the normal operation of nuclear facilities, further guidance on its application in post-accident situations is needed.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=105 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Retrieving damaged fuel and characterizing and removing fuel debris require solutions that are specific to the accident and special methods and tools may need to be developed.
A reactor accident involving damage to the nuclear fuel results in unique conditions within the reactor and with regard to the fuel debris. Different plans for characterizing and removing damaged fuel and debris will need to be developed and carried forward to various degrees until one of the plans, or a combination of them, is considered to be the preferred method.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=105 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Decisions on interim stages and the end state of the site and the damaged reactors will need to take into account many factors that are difficult to evaluate at present.
Such decisions will depend on the condition of the damaged reactors, fuel and debris, which cannot yet be determined in detail. Factors to be considered in the decision making include the potential dose levels for decommissioning workers, the volume and type of waste generated and the efforts required for waste treatment. The decision making process on the end state will need to include a dialogue with stakeholders.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=105 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
It is essential to establish an integrated management structure for maintaining stabilization, preparing for decommissioning and carrying out decommissioning activities.
The challenges of post-accident preparations for decommissioning are different from those of a normally operating plant. Long term stabilization and preparations for decommissioning depend upon the input from many organizations, and an integrated approach is needed to ensure that these efforts are effectively and efficiently managed. An organizational structure that is focused solely on decommissioning of the damaged site may be necessary.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=105 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
Establishing and maintaining long term knowledge and technical expertise is essential for successful decommissioning.
Post-accident preparations for decommissioning will take decades. Arrangements for maintaining the necessary expertise throughout this entire period are necessary.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=105 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
National strategies and measures for post-accident recovery need to include the development of a generic strategy for managing contaminated liquid and solid material and radioactive waste, supported by generic safety assessments for discharge, storage and disposal.
Such a strategy would assist in the implementation of pre-disposal management (for example, handling, treatment, conditioning and storage) of accident generated contaminated material and radioactive waste. It could also suggest appropriate routes for the disposal of materials. Waste management strategies may involve the use of existing processing, storage and disposal facilities, such as incinerators or leachate controlled landfills, but other approaches may be necessary, depending on the volumes and characteristics of the wastes involved. The development of such strategies could be supported by the development of a generic safety case.
Reference Document: The Fukushima Daiichi Accident - Technical Volume 5 - Post-accident Recovery
Link to Reference Document: <a href=http://www-pub.iaea.org/MTCD/Publications/PDF/AdditionalVolumes/P1710/Pub1710-TV5-Web.pdf#page=145 target='_blank' alt='Open site in new window'><img src='/FukushimaLessonsLearned/Images1/Thumbnails/external-link-xxl.gif' style='height:25px; width:25px;' /></a>
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