The International Atomic Energy Agency has issued a final report about the decommissioning of the Fukushima Daiichi nuclear power plant, based partly on a second visit to the site in November-December 2013 and meetings with government and regulatory officials. The visits were requested by Japan.

The report is both supportive, highlighting 19 areas of progress, and elsewhere offers criticisms and Advisory Point, in particular 19 advisory points.

Among other things, the report seems to favour controlled releases of treated water to sea, and seems to have concerns about what might be overly-restrictive radiation levels required for members of the public.

It says:
"The IAEA team considers that Japan developed its efforts towards decommissioning the plant promptly after the accident, and since then, Japan has achieved good progress in improving its strategy and the associated plans, as well as in allocating the necessary resources towards the safe decommissioning of TEPCO's Fukushima Daiichi NPS.

"Since the first IAEA mission in April 2013, the Government of Japan and TEPCO have adopted a more proactive attitude and approach towards addressing the many difficulties at the site.

"The IAEA team also notes that the current situation is very complex, and that there are still some challenging issues (e.g., contaminated water management, nuclear fuel removal, and fuel debris removal) that must be resolved to achieve the long-term stable condition of the plant. In light of these challenges, Japan appears to have adopted a well-oriented set of countermeasures."

An edited version of the acknowledgements and Advisory Point is below.

1. Revised roadmap

Acknowledgement 1: The IAEA team acknowledges that the revised Roadmap was developed based on more- realistic assumptions, a reflection of the current knowledge of the condition of each specific unit, and the feedback and opinions from stakeholders.

Advisory Point 1: The IAEA team encourages the Government of Japan to continue leading and promoting efforts towards the safe implementation of the decommissioning of TEPCO's Fukushima Daiichi NPS.

2. Public relations and communication

Acknowledgement 2: TEPCO has become more proactive in implementing public information and communication activities.

Advisory Point 2: Recognizing the efforts by the Government of Japan to communicate with a variety of local stakeholders, the IAEA team urges METI to move forward for establishing the Fukushima Advisory Board without delay so that it can begin engaging stakeholders in a more structured manner.

Advisory Point 3: TEPCO should consider revising its communication strategy by expanding its targeted stakeholders to include on-site staff and contractors.

3. Spent fuel removal and fuel debris removal

Acknowledgement 3: The IAEA team recognizes the substantial efforts made by TEPCO in transitioning the Unit 4 refuelling floor to a state in which the first fuel assemblies could be removed in November 2013, thus completing a major milestone one month ahead of the original plan.

Acknowledgement 4: The IAEA team recognizes that individual plans for the recovery of fuel from Units 1-3 have been developed and that the plans include hold points and contingency options.

Advisory Point 4: The IAEA team advises TEPCO to consider alternative options and additional measures to support the on-going fuel storage operations in the Common Spent Fuel Pool and future fuel disposition.

Acknowledgement 5: The IAEA team recognizes TEPCO's and IRID's efforts to develop remote technology to identify water leakage locations in primary containment vessels (PCVs) and the supporting development work on techniques for fixing these leaks.

4. Management of contaminated water

Acknowledgement 6: The IAEA team acknowledges the proactive steps taken by the Government of Japan to address the contaminated water issue, including the formulation of policies and the establishment of the Committee on Countermeasures for Contaminated Water Treatment.

Acknowledgement 7: The IAEA team acknowledges the continued successful use of the caesium removal system to treat contaminated water accumulated in the reactor and turbine buildings, with consistently high system availability and performance.

Advisory Point 5: The IAEA team believes it is necessary to find a sustainable solution to the problem of managing contaminated water at TEPCO's Fukushima Daiichi NPS. This would require considering all options, including the possible resumption of controlled discharges to the sea.

Advisory Point 6: The IAEA team encourages TEPCO to continue, and even intensify, its efforts to improve the performance and enhance the capacity of ALPS to be able to meet these goals as planned.

Acknowledgement 8: TEPCO has taken a more proactive role in identifying and permanently controlling leakage issues instead of a reactive role that focused on the mitigation of consequences and the treatment of symptoms by provisional countermeasures.

Advisory Point 7: The IAEA team emphasizes the importance of establishing a thorough and structured impact review process.

5. Management of radwaste

Acknowledgement 9: The on-going treatment of contaminated water is resulting in the generation of large volumes of secondary waste streams that have high levels of radioactivity.

Acknowledgement 10: The IAEA team acknowledges that TEPCO is on the way to optimising the classification and handling of the solid waste to minimise volumes by reducing generation and recycling non- or low-contaminated waste.

Advisory point 8: As radiological characterisation and waste classification are important for developing a long- term waste management strategy, establishing an on-site or near-site facility for radiological characterisation of the waste should be accelerated.

Advisory point 9: As decommissioning activities progress, large amounts of waste will continue to be generated and may require on-site storage for a long period of time.

Acknowledgement 11: The IAEA team acknowledges further progress in developing and implementing a comprehensive research and development (R&D) programme to support the management of waste generated during the emergency phase and during pre-decommissioning and decommissioning activities at TEPCO's Fukushima Daiichi NPS.

Acknowledgement 12: TEPCO has provided a comprehensive and multi-barrier approach to control the flow into and out of the reactor and turbine buildings.

Advisory point 10: The IAEA team encourages TEPCO to advance the implementation and careful monitoring of its measures to reduce the ingress of groundwater into reactor and turbine buildings and to prevent radioactive releases.

Advisory point 11: The IAEA team encourages TEPCO to continue to ensure that during the detailed planning stage an evaluation is performed (as a series of 'what if' scenarios) of the resilience of the overall approach to controlling the flow of groundwater into and out of the reactor and turbine buildings (and trenches).

Advisory point 12: As advised by the April 2013 mission, the IAEA team reiterates that the Government of Japan and TEPCO should establish constructive discussions with relevant authorities and stakeholders, including the NRA and local authorities, to assess and balance the risks and benefits of the dose limit at the boundaries and its practical implementation, particularly from direct exposures at the site-boundary arising from contaminated solids and accumulated liquids on the site and for the possibility of controlled liquids discharges from the site.

Advisory point 13: Considering that controlled water discharges to the sea could be necessary in the future to achieve the long-term stable situation on-site and to reduce risks of accidental leakages as well as exposure to workers, the IAEA team encourages TEPCO to prepare safety and environmental impact assessments of this possible practice based on the limit of 1 mSv/year established by the NRA for the population, and to submit it to the NRA for the necessary regulatory review.

Acknowledgement 13: The IAEA team acknowledges all the Japanese stakeholders for the commendable work they are performing on Fukushima's activities towards decommissioning and particularly for beginning discussion about the end state of decommissioning process, even if it involves a several decades schedule.

Acknowledgement 14: Authorization process for the fuel removal from the spent fuel storage pool of Unit 4 to the Common Spent Fuel Pool was conducted in an efficient way between TEPCO and the NRA.

Advisory point 14: The Roadmap introduces hold points prior to the commencement of some activities. These hold points were introduced mainly due to the need to make technical decisions and to select and develop technical options for implementing activities. The IAEA team suggests that the licensing hold points should be integrated into the Roadmap or its implementing documents in order to include points of important regulatory decisions and to account for the time needed for regulatory reviews and approvals prior to commencing certain activities or implementation phases.

Acknowledgement 15: The IAEA team visited the remote-control room for operating robotic equipment that is being used for clearing rubble from the top floor of Unit 3. This is an excellent beginning for what will be ever-increasing needs for remotely operated equipment for many diverse future tasks.

Acknowledgement 16: Establishing a working group for developing remotely operated equipment has resulted in shortening the time between identification of a specific need and delivery of individual remote technology equipment.

Acknowledgement 17: The IAEA team acknowledges the efforts that have been implemented by the focused reliability improvements, quality assurance, countermeasure project, contaminated water treatment organizations and the site personnel as a sign of the utility's progress toward taking a more anticipatory role in identifying and controlling equipment issues instead of a reactive role.

Advisory point 15: The IAEA team suggests that TEPCO revisit the assumptions, especially on service lifetimes and other technical specifications, of the SSCs placed as a prompt action immediately following the accident as well as to consider conservative lifetime assumptions in design of new SSCs.

Advisory point 16: The IAEA team suggests that specific measures to control and to sample run-off storm water from each storage facility are taken to minimise the potential dispersing contamination through ground/storm water.

6. Marine monitoring

Acknowledgement 18: A comprehensive "Sea Area Monitoring Plan" was established with a detailed description of sampling positions, including depth distribution, frequency of sampling, detection limit of the analysis to be performed, and indication of the responsible entity.

Acknowledgement 19: Wherever possible, a number of countermeasures were implemented to protect further contamination of the marine environment, such as isolating and removing the contamination sources and preventing leakages.

Advisory point 17: Because about 10 Japanese institutions are involved in marine monitoring, it is advised to perform interlaboratory comparisons to ensure the high quality of data and to prove the comparability of the results.

Advisory point 18: Interpreting the data and presenting it to the public in an understandable, but scientifically correct, way is extremely important but not always simple.

Advisory point 19: The IAEA team encourages relevant counterparts to consider installing underwater in-situ measurement detectors close to the TEPCO's Fukushima Daiichi NPS site to measure continuously the concentration of gamma-emitting radionuclides in seawater.

Photo: IAEA experts visiting TEPCO's Fukushima Daiichi Nuclear Power Station on 27 November 2013 looked at the fuel assembly removal process in Reactor Unit 4.