Based on the findings made by scholars and experts in technology, safety, economy, politics, culture and natural environment, the government has adopted the following management strategy for spent nuclear fuel: "storage in spent fuel pools for the near term, onsite dry storage for the mid-term, and final deep geological disposal for the long term".
"Deep geological disposal" is generally adopted worldwide for high level radioactive waste (HLRW) management. The spent nuclear fuel is encapsulated in a metal canister and then placed into an engineered facility within the bedrock at 300-1000 meters depth. Such a multiple barrier system, comprising both engineered and natural barriers, will efficiently retard the migration of radionuclides, long enough for them to decay to a safe level before reaching the biosphere.
Since December 1983, several organizations were involved in a task force to draft the "Research Plan on Spent Nuclear Fuel" and they carried out all 4 stages of HLRW final disposal research and development. These organizations included the Atomic Energy Council (AEC), Taiwan Power Company (TPC), Institute of Nuclear Energy Research (INER), Central Geological Survey (CGS) and Energy and Resources Laboratories (ERL) of Industrial Technology Research Institute (ITRI).
The "Nuclear Materials and Radioactive Waste Management Act" was issued in December 2002 and its Enforcement Rule was issued the next year. The Act states that the producer of HLRW (TPC) is responsible for the implementation of final disposal and is required to submit a final disposal plan for HLRW within two years after the Act came into effect. In Dec. 2004, TPC submitted the "Spent Nuclear Fuel Final Disposal Plan" to AEC. The plan was reviewed and approved in July, 2006. The "Spent Nuclear Fuel Final Disposal Plan" will be carried out in five phases: (1) Potential host rock characterization and evaluation; (2) Candidate site investigation and confirmation; (3) Detailed site investigation and testing; (4) Repository design and license application; and (5) Repository construction. Finally, a deep geological disposal repository is expected to be operational in 2055.
The Act required the TPC to carry out the scheduled disposal plan. The enforcement rule required that TPC shall submit to the AEC an annual report on the implementation of the plan for the previous year before the end of February, and the work plan for the next year by the end of October. The disposal plan shall also be reviewed and revised every four years. In 2010, 2014 and 2018, TPC submitted a revised version of the disposal plan for reviewing. The latest version of the disposal plan was approved in January, 2020 by AEC.
According to the schedule of the plan, TPC was required to submit the "Spent Nuclear Fuel Disposal Program - 2009 Progress Report" (which is a technical feasibility progress report) by September 2009. This progress report was submitted to AEC in September, 2009, and was reviewed and approved in July, 2010. In addition, TPC is also required to submit The "Spent Nuclear Fuel Disposal Program - 2017 Progress Report (SNFD 2017 report)" to demonstrate the technical capability of spent nuclear fuel final disposal in Taiwan by the end of 2017. AEC has requested TPC to carry out an international peer review to ensure the sufficiency and credibility of the report.
The main regulatory activities in the future will be the review, approval and on-going inspection of construction, operation, design changes and equipment modification.
Key requirements for the final disposal of HLRW are as follows:
- Site requirements
- The HLRW disposal facility shall not be located in the following areas: (1) where there is active faulting, (2) where the geochemical conditions are unfavorable for effectively suppressing the diffusion of radionuclides, (3) where the surface or underground hydrologic and geologic conditions are likely to endanger the disposal facility, and (4) areas of high population density.
- In addition, the site selection shall avoid areas: (1) where there is a possibility of landslide, land subsidence and volcanic activities, (2) where the geologic structure may obviously change, (3) where the hydrologic conditions could easily change, (4) the host rock for disposal shows obvious deterioration, or (5) the lithosphere is obviously raised or corroded. If the aforesaid conditions exist, the operator shall provide solutions for ensuring the HLRW disposal facility complies with the safety requirements.
- Site characterization investigation application and operational stipulations
The applicant for the HLRW disposal facility shall submit a detailed site investigation plan to the AEC. The detailed investigation can only commence after being approved. The plan shall contain (1) site description, (2) conceptual design of the operating area, (3) necessity and planning for drilling and excavation, (4) research and testing activities, (5) counter-measures for investigative activities that may compromise the isolation capability of the site, (6) quality assurance plan, (7) rehabilitation plan, and (8) financial statement for the investigation.
- Design requirements
The HLRW disposal facility shall adopt the multi-barrier design; the facility shall be designed so as to ensure that the annual effective dose equivalent to the general public outside the facility is less than 0.25 mSv, and the annual risk is less than 10-6 for a representative individual in the offsite critical group.