Most SRAW consists of dry active waste (DAW) and secondary process waste. The DAW is generated during maintenance and repair of contami­nated systems and includes items such as used parts, paper, clothes, gloves and shoes. Secondary waste is generated from the liquid RAW treatment system and includes concentrated wastes from evaporators, spent resin from demineralizers, and spent filters from liquid purification systems.

Laundry waste ►

Other
liquid
waste
>

Filtration Evaporation desalinization concentration

The DAW is compressed by a conventional compactor (capacity: 2,000 tons) into 200 L drums. Solidification by Portland cement, which had been commonly applied in the past, is no longer used. Instead, the concen­trated waste is now dried and stabilized by paraffin wax in drums, and spent resin is kept in a high-integrity or equivalent container after drying in the spent resin drying facility. Spent filters are stored in shielded high integrity containers (HIC).

To ensure its safe discharge into the environment, liquid radioactive waste has to fulfill very strict requirements connected with the limits of radioac­tive substances and other impurities (suspended particulates, chemical, bio­logical, heavy metals, etc.). To achieve the standards described in national

regulations, radioactive waste has to be treated, including volume reduction and reduction of radioactive compounds and other solutes in the effluent.

NPPs currently in operation in Korea have their own gaseous, liquid, and solid waste treatment facility and on-site storage facilities to ensure the safe management of RAW generated in the process of operation. The gaseous waste treatment system comprises gas decay tanks and/or charcoal delay beds. The liquid waste treatment system is equipped with either liquid waste evaporators or selective ion exchangers. The solid waste treatment facility has spent resin drying systems, spent filter processing and packaging systems, concentrated waste drying systems, and dry waste compactors. The RI waste generated from domestic medical research, industrial RI users, and research institutes is collected and stored at the Central Research Institute (CRI) of KHNP in Daejeon. Around 90% of LILW comes from NPP and the rest arises from industry, medicine, and research institutes.

Generally, the type of LILW is classified as follows:

• power plants: dry active waste, spent resin, spent filter, and concentrated waste

• non-power plant sources (RI waste): dry active waste (combustible or non-combustible), hepatitis waste, organic liquid waste, spent sealed source, spent resin, spent filters, and concentrated waste.

Figure 21.3 summarizes the process steps for treatment of solid, liquid and

gaseous wastes in Korea.

Radioactive wastes arise from the generation of electricity in nuclear power stations and from the use of radioactive materials in industry, medicine, research, and military. There is a wide spectrum of wastes, from those that contain high concentrations of radioactive materials, to general industry and laboratory wastes which are only lightly contaminated with activity.

The Atomic Energy Act (AEA, Article 2.18) of the Republic of Korea defines ‘radioactive waste’ as radioactive materials or materials contami­nated with radioactive materials which are subject to disposal, including spent fuel. The Enforcement Decree of the AEA defines high-level radioac­tive waste (HLW) as radioactive waste with radioactivity concentration and heat generation over the limiting volume specified by the Ministry of Edu­cation, Science, and Technology (MEST). In the strict sense, wastes other than HLW belong to the LILW category in accordance with the AEA. The limiting values on radioactivity and heat generation rate are specified in the MEST Notice No. 2008-31 (Notice of the Standards on Radiation Protec­tion, etc.) [MEST, 2008] as follows:

• radioactivity: >4,000 Bq/g for alpha-emitting radionuclides with a half­life of longer than 20 years

• heat generation rate: >2 kW/m3.

The AEA also defines the clearance level adopted from the ‘exempt waste’ concept of the IAEA radioactive waste classification. The clearance levels in Korea are such that annual individual radiation dose shall be less than 10 pSv/y and the total collective dose below one person-Sv/y concurrently. These are the same as the levels specified in the IAEA Safety Series No. 115 (1996) [IAEA, 1996].

All radioactive wastes are still to be stored in on-site temporary storage until a permanent disposal facility has been constructed. The amount of radioactive waste being stored by April 2012 is 89,865 drums from nuclear power plants (KHNP, 2012). (Hereafter, ‘drum’ means ‘200-liter drum equivalent’ unless otherwise stated.) The total capacity of temporary storage in NPP sites is 109,900 drums and the accumulated radioactive waste stored at each NPP site is around 77.7% of their storage capacity, as shown in Table 21.1 . Although the volume of waste arising from radioisotope use is still relatively small compared to power reactor waste volume, the annual gen­eration rate is expected to rise rapidly as industrial use of radioisotopes increases. The waste type and volume of LILW is shown in Fig. 21.2.

The safe management of RAW is recognized as an essential national task for sustainable generation of nuclear energy and for energy self-reliance in South Korea. Since the early 1980s, the Korean government has attempted to prepare a disposal site for safe management of RAW but failed to secure one due to lack of public consensus and acceptance. In this context, the Atomic Energy Commission (AEC) of the Korean government, the highest decision-making body for nuclear energy policy, approved the ‘National

Radioactive Waste Management Policy’ at the 249th meeting held on Sep­tember 30, 1998. This policy stipulated that a LILW facility would be con­structed and operated by 2008 and a centralized spent fuel interim storage facility by 2016. The key principles of the national policy on radioactive waste management are as follows:

• direct control by the government

• safety as top priority

• minimization of waste generation

• ‘polluter pays’ principle

• transparency for site selection process.

However, a revision of the government policy was made at the 253rd AEC meeting on December 17, 2004, after the government failed repeatedly to find a candidate site for the radioactive waste management complex. There­fore, a new government plan for radioactive waste management was announced, basically to separate the sites for the LILW disposal facility and the spent fuel interim storage facility instead of constructing both facilities on one site. The LILW disposal facility is now being constructed in Gyeongju after local referenda. Conversely, the key decision to directly dispose of or recycle spent fuel has not yet been made in Korea. Spent fuel is currently stored at reactor sites under the responsibility of Korea Hydro and Nuclear Power Co. (KHNP), because the 253rd AEC meeting stipulated that the national policy for spent fuel management will be decided later, taking account of domestic and international technological developments.

Spent fuel (SF) generated from nuclear power plants has been stored in spent fuel storage pools at reactors or in on-site dry storage facilities. Dry storage is currently used only for PHWR (CANDU) spent fuel sufficiently decayed for about six years in storage pools. The low — and intermediate — level radioactive waste (LILW) generated from the NPPs has been stored in on-site radioactive waste storage facilities.

Radioactive waste materials are also generated from fuel fabrication processes and they are stored on-site. In addition, the use of radioactive materials in medicine, research work and industry has increased steadily. These facilities are located throughout the country and generate various types of RAW. Radioisotope (RI) contaminated waste from these facilities is stored at an RI waste management facility. There has been much turmoil concerning public acceptance issues associated with the LILW disposal facility site selection, with a number of unsuccessful attempts to select the site.

The Korean government has striven to secure a disposal site for the safe management of RAW since the early 1980s. After a number of failed attempts, the Korean government issued a Public Notice on the selection of a candidate site for the LILW disposal facility, and the city of Gyeongju was selected as the final candidate site in November 2005 following the procedures involving a site suitability assessment, local referenda, etc. as specified in the Public Notice. The Korea Radioactive Waste Management Corporation. (KRMC) was established in 2009 as a new Korean RAW management agency and is currently undertaking the construction of the LILW disposal facility in accordance with the permit issued.

Spent fuel generated from NPPs is stored in the spent fuel storage facility in each unit. The storage capacity for spent fuel has been expanded as a consequence of the delayed construction schedule of the away-from-reactor (AFR) interim storage.

Korea’s nuclear development has been robust and steady. The data shows an unplanned shutdown rate of 0.3 trips/reactor/yr and capability loss of 0.36% in 2009, the best record in the world. Its long-term energy plan entails increasing the nuclear installed capacity to 41% and nuclear generation to 59% of the total capacity and production by 2030.

The Korean government has maintained a consistent national policy for a stable energy supply by fostering nuclear power industries to offset the lack of other energy resources in the country. Nuclear power accounted for
31.3% of the total electricity generation in Korea in 2010 [MEST, 2010]. Since the commencement of the first commercial operation of Kori Unit 1 in April 1978, 21 nuclear power plants (NPPs) are commercially operating as of 2011 with an installed capacity of 18,716 MWe. Four units out of the 21 operating NPPs are pressurized heavy water reactors (PHWRs) at the Wolsung site. The remaining 17 units, located at the Kori, Yonggwang and Ulchin sites, are pressurized light water reactors (PWRs) (Fig. 21.1). There are seven units (three units of OPR 1000, four units of APR 1400) under construction; in addition, six units are in the planning stage of construction.

All nuclear plants are operated by KHNP (Korea Hydro & Nuclear Co.). In addition to the domestic nuclear plant construction, Korea is building four nuclear units of Korean design (APR 1400) in the United Arab Emirates.

In August 2008, the government set out a plan to significantly reduce the nation ’s dependency on fossil fuels and more than quadruple the use of renewable energy by 2030. In addition, nuclear power will expand to account for 27.8% of total energy consumption in 2030 compared to 14.9% in 2007. The International Atomic Energy Agency (IAEA) officially recognized the Republic of Korea’s nuclear transparency by approving the broader conclu­sion at the regular meeting of the IAEA Board of Governors held in June

2008.

The energy situation in Korea is worse than in many countries, as Korea has no viable natural energy sources and must import primary energy. In 2011, Korea imported approximately 97% of its primary energy. South Korea is the world’s No. 5 crude oil buyer and No. 2 liquefied natural gas importer and has boosted spending to acquire assets and develop oil and gas reserves, with a heavy focus so far on the Middle East and the Arctic. As a result, Korea is currently the ninth largest emitter of greenhouse gases in the world. Korea’ s greenhouse gas emission rates are increasing at the fastest rate (2.8%) in the world.

An important agenda in Korea’s energy development plan is to promote nuclear power as a strategic response in the post-fossil fuel era and as a pillar of energy security and independence. Korea mapped out its long-term energy development plan based on the 3Es — energy security, economic efficiency and environmental protection. Korea hopes to reach its long-term energy goals by

• improving energy efficiency and reducing energy consumption,

• promoting clean energy including nuclear and renewable energy to reduce dependence on fossil fuels,

• boosting the green energy industry, and

• making energy sources accessible and affordable to low-income households.

Korea’s total installed electricity generation capacity, standing at 72,491 MWe as of 2008, is projected to grow to 95,115 MWe by 2020 and further to 105,195 MWe by 2030. According to the Carbon Dioxide Information Analy­sis Center (CDIAC), Korea is the ninth highest country in carbon dioxide emissions in the period 1950-2005. USA (25%), China (10%) and Russia (8%) are the top countries in carbon dioxide emission in 1950-2005.

The Korean government is focusing its efforts on nuclear power as part of a national strategy to reduce greenhouse gas emissions and to achieve low carbon sustainable growth, Korea aspiring to become a green power country with low carbon, green growth. The national vision is to become the world’s seventh largest green power by 2020 and the fifth largest green power by 2050.

J.-I. Y U N, Y. H. J E O N G and J. H. KIM, KAIST, Korea DOI: 10.1533/9780857097446.2.673

Abstract: Republic of Korea currently operates 21 nuclear units providing one-third of the nation’s electricity. Low and intermediate level radioactive materials emanating from these plants, medical facilities, research reactors, and industry need to be safely stored and managed. Disposal of spent nuclear fuel is also an important national issue. This chapter reviews the current state of affairs in Korea and examines the national policy, strategy, and direction for managing spent fuel and radioactive waste (RAW) materials. Decontamination of waste materials is also discussed.

Key words: Republic of Korea, radioactive waste (RAW), spent nuclear fuel (SNF) storage, disposal, decommissioning, decontamination.

21.1 Introduction

The twenty-first century’s grand challenges are aptly characterized by energy, environment, and economy — the so-called tri-lemma of sustainabil­ity. These three Es are intricately interconnected, and balancing them is necessary for a healthy society. Many of this century’s issues are global in nature, such as global warming that cuts across national boundaries and requires global cooperation in energy, environment, and economy to solve them. We are all in the same boat and must work together to meet these formidable challenges.

According to the International Energy Outlook 2011 reference scenario, the world’s energy consumption is expected to grow by 53% between 2008 and 2035. Global electricity generation will grow from 19.1 trillion kWh in 2008 to 35.2 trillion kWh in 2035, an increase of 84%. Likewise, nuclear generation is expected to increase from 2.6 trillion kWh in 2008 to 4.9 tril­lion kWh in 2035. As for Korea, energy is particularly crucial for its national growth planning, as Korea has virtually no natural resources.

During the time when economic sanctions were in force against South Africa, many nuclear fuel cycle activities were developed indigenously. Uranium production has generally been a by-product of gold or copper mining but, with the increased demand and prices today, further exploration is in progress. Originally, fuel for Koeberg was imported but, because of

(a)

(b)

20.14 ( a, b) Decontamination of historical conversion plant to re-use facility [1].

sanctions, the Atomic Energy Corporation set up conversion, enrichment and fuel manufacturing services for Koeberg. Enrichment was done at Pelindaba. For research reactor and military use, 45% enriched uranium was produced and for Koeberg low enriched material. Operations were halted in 1990 and 1995, respectively.

The new South African nuclear policy advocates re-development of the country’s nuclear capabilities. It potentially allows for the country to imple­ment conversion and enrichment facilities in order to gain more benefit from its uranium reserves. The ambitious programme goes still further and spans the full nuclear fuel cycle, to include fuel fabrication, reprocessing and recycling. The explicit policy goal is ‘attainment of global leadership and self-sufficiency in the nuclear energy sector in the long term’ [17]. An inves­tigation commissioned by the Department of Minerals and Energy con­cluded that it would not be advisable to exclude the reprocessing, conditioning and recycling of used fuel. Both national and foreign reproc­essing options are conceivable and the government has requested that these options be investigated.

An integrated waste management strategy must take into account all of the radioactive wastes from all nuclear activities — in the past (legacy wastes), currently (mining, power production, medicine, industry and research) and in the future (decommissioning and, potentially, enrichment, fuel fabrication and reprocessing). This implies that, despite its present modest nuclear programme, South Africa must address a range of waste management issues as wide as that in the most developed nuclear countries of the world. New issues will arise if fuel cycle activities are expanded. For example, experience in the UK and other countries has shown that, if reprocessing is undertaken, then waste streams become significantly more diverse and new questions, such as whether surplus plutonium is a resource or a waste, must be addressed [18]. This emphasizes the need for a compre­hensive and integrated waste management strategy and operational pro­gramme. In the present report, however, attention is focused on the management of the wastes from power production and, in particular, on the SF and HLW.

Regardless of any HLW management strategy chosen in the future, a deep geological repository is needed, as long-term storage of SNF and HLW is not considered attractive but recognized as an interim option. Suitable high isolation environments are available in South Africa to host a deep geological repository. However, the development of a deep geological

repository is a multidisciplinary process, by nature involving legal, technical, safety, economic, but also societal requirements/constraints. For the selec­tion of a site for long-term management of SNF and HLW, public participa­tion will be included.

The following has been completed as part of the process to establish a deep geological disposal repository:

• The potential of the current Vaalputs site to be used as a deep geological disposal site was investigated by Necsa during the early 1990s. The initial schematic concept can be seen in Fig. 20.16.

• Eskom completed feasibility studies with regard to geological disposal site selection, repository design, R&D requirements, interim storage, encapsulation plant, SNF transportation in 2007.

• Eskom ‘Technical SF Management Plan’ based on direct disposal (for costing and planning purposes).

Similar to nuclear programmes worldwide, the uranium conversion and enrichment research and production projects in South Africa were termi­nated in the early 1990s. During this time, the decommissioning strategy was aimed at returning the Necsa site to greenfield. To achieve this, the final disposal of waste, demolition of all buildings and the remediation of a site to conditions prior to any development was considered. Currently, demoli­tion is no longer considered as a final decommissioning phase and, as the demand for nuclear facilities increases (nuclear renaissance), redevelop­ment and re-use (R/R) after decommissioning are currently envisaged for the buildings on the Necsa site. This will ensure a holistic approach based on current and projected future redevelopment demands. The new redevel­opment and re-use plan aims to allocate previously licensed buildings to similar or the same nuclear projects as housed originally in the specific building, thus meeting most of the design requirements. There are various buildings on the Necsa site that are currently in a decommissioning or a care and maintenance phase that will now be evaluated to ensure the opti­mization of decommissioning costs and waste minimization. The possible reutilization of process equipment could prevent unnecessary generation of waste and the implementation of additional radiological protective meas­ures resulting in decommissioning costs.

Currently, conceptual decommissioning plans exist for most nuclear facil­ities and these plans will be explored to include possible redevelopment options. Emphasis shall be on the preservation of buildings and infrastruc­ture, to keep them structurally sound and operable. For example, the decom­missioning, decontamination and possible reutilisation of the uranium conversion facility at Necsa (Fig. 20.14) could have a major influence on the new Necsa nuclear fuel cycle initiative ’s business strategy and plan and waste management. Decommissioning projects aim at waste minimization by ensuring effective equipment and technology are used and proper seg­regation of waste is applied.