[Korea`s nuclear technology (8)] Korea develops world`s best research reactor

This is the eighth in a series of articles that highlight the challenges and opportunities facing Korea`s nuclear power industry. -- Ed.





By Ha Jae-joo



Korea is operating 20 nuclear power plants that account for 38 percent of electricity consumption, with eight new nuclear plants under construction. Korea ranks sixth in the world in terms of nuclear power generation capacity.

Considering that Korea ranks ninth in energy consumption, seventh in oil consumption and fourth in oil import in the world, nuclear energy assumes an important role in the Korean economy as an alternative to fossil fuels.

For the last 20 years, consumer prices in Korea increased by 186 percent, while electricity tariffs increased only by 11.4 percent. Needless to say, this stable supply of low-cost electricity contributed greatly to the continued growth of the Korean economy. Korea could keep electricity rates low thanks largely to its continuous investment in R&D in nuclear technology.

Korea`s investment in nuclear R&D started from the establishment of the Korea Atomic Energy Research Institute in 1959. In the preceding year, the Korean government decided to build a research reactor, selecting a 100 kW TRIGA MK-II reactor as the first Korean research reactor (KRR-1).

Research reactors are different from power reactors. The primary purpose of research reactors is to produce neutron beams used for research and other purposes, while the primary function of power reactors is to produce heat to make electricity. Research reactors are small and simple compared to power reactors. They operate at lower temperatures, need far less fuel, and turn out far less fission products as the fuel is used.



The introduction of a research reactor was the first step Korea made to open the nuclear technology era. KRR-1 was constructed under a turn-key deal, with Korean construction companies participating in its installation. The initial criticality -- the point at which a nuclear reaction is self-sustaining -- was achieved on March 19, 1962.

The Korean government began to discuss the introduction of a megawatt-level research reactor in the mid-1960s, with the final decision to import a 2 MW TRIGA MK-III made in 1968. A plan to introduce nuclear power reactors by the end of the 1970s was the background to the decision.

These two research reactors paved the way for Korea`s rise as a powerhouse in nuclear technology and power generation. They helped Korea develop human resources, develop basic nuclear technology and master research reactor utilization technology. KRR-I and KRR-II were permanently shut down in 1995. The Korean government decided to turn KRR-1 into a nuclear museum. KRR-II was decommissioned in 2005.

Kyung-Hee University in Seoul is one of the seven Korean universities that have a nuclear engineering department. In 1976, Colorado State University of the United States donated an AGN-201K, whose critical assembly was 0.1 W, to Kyung-Hee. This research reactor started operation in 1982. From 2004 to 2007, it underwent a refurbishment and power uprate project. In 2008, it restarted operation as a 10 W reactor. It is being used for training of university students and HANARO reactor operators.

This is a good example that an old facility can remain relevant after an upgrade.

In the mid-1980s, Korea considered the development of a high-power research reactor in recognition of the need to provide a neutron source for basic research and other purposes, including the need for an irradiation test tool for research on reactor fuel and reactor materials. A high-power research reactor would also facilitate radioisotope production.

Korea started to build HANARO, a 30 MW open-pool type multipurpose research reactor, in 1985. The HANARO project was one of Korea`s ambitious projects to advance its nuclear technology. Korea intended to localize not only the design and fabrication of nuclear power reactor fuel but ultimately the design of power reactors.

The HANARO project, led by KAERI, called for a combination of various indigenous technologies ranging from design to commissioning. Its initial criticality was achieved in February 1995 and has since been used for various purposes. Figure 1 shows the HANARO complex which is composed of the HANARO building, the Radio-Isotope Production Facility, the Irradiated Material Examination Facility, and the Cold Neutron Laboratory. The construction of the first three facilities was completed in 1994, while the CNL was added in 2008.

Figure 2 offers a view of the inside of the HANARO reactor building; Figure 3 shows the reactor core; and Figure 4 shows the use of vertical and horizontal tubes together inside the reactor core.

HANARO is one of the world`s best multipurpose research reactors. It is the only research reactor in the world that is capable of undertaking all the functions that a research reactor can carry out. It can be used for neutron science, reactor material and fuel irradiation, radioisotope production, neutron transmutation doping, neutron activation analysis, and neutron radiography.

To accommodate an expanding list of applications, new utilization facilities have been added since the reactor reached initial criticality. In addition, reactor systems have been upgraded and antiaging steps have been taken to keep the reactor in good condition.

Recent achievements include the installation of a fuel test loop and a cold neutron research facility. The fuel test loop in HANARO enables a simulation of the thermal-hydraulic conditions of the power reactor. A commissioning test including the test fuel irradiation was successfully completed in September 2009.

With the introduction of a fuel test loop, Korea can now conduct the whole process of reactor fuel production -- from designing and fabricating to testing new power reactor fuels -- without recourse to foreign assistance. Previously, it had to rely on foreign facilities to test the performance of its newly developed reactor fuels, risking the exposure of its expertise in fuel development to foreign rivals.

Development of new reactor fuels is needed to increase the operating efficiency of power reactors and lower the cost of reactor fuels. Hanaro has been using KAERI-made fuel since 2005.

KAERI has become a world leader in research reactor fuel technology. It has developed an atomized technique which produces high quality research reactor fuel material. Recently, the Japan Atomic Energy Agency has informed KAERI that it would introduce Korea`s reactor fuel technology to the Japan Materials Testing Reactor, an indication that Korea`s reactor fuel technology is internationally recognized.

The cold neutron research facility represents another important milestone in Korea`s nuclear technology development history. A cold neutron is a very low-energy neutron with a long wave length in the nanometer range. In radiography, cold neutrons increase the image contrast and improve the detection of small amounts of water and hydrogen-containing materials in metal matrixes. HANARO`s production of cold neutron beams makes it an inevitable tool for research on biomaterials and nanomaterials.

On Sept. 3, 2009, the first cold neutron measurement was conducted at 30 MW, and the results satisfied neutron scientists. Its neutron flux, or the number of neutrons passing through 1 sq. centimeter of area per second, was measured at 6.0 x 107, a level that matched the estimate made in the design phase. In terms of neutron quality, Hanaro ranks third in the world, following ILL of France and FRM-2 of Germany.

The cold neutron research facility and other utilization facilities will help HANARO emerge as a major neutron source available in the Asian region.

KAERI has long sought to share its experiences in development, management and utilization of research reactors with foreign countries. Its efforts have resulted in the training of foreign research reactor operators, exports of fuel materials and overseas supply of small equipment used for radio-isotope production and neutron beam research.

In 2007, Netherlands Research and Consultancy Group of the Netherlands invited KAERI to participate in a bid for an 80 MW research reactor, called PALLAS. NRG has operated HFR, a 45 MW research reactor, since 1961 and has considered building a replacement of HFR.

In contrast to a power reactor, the design of a research reactor should reflect the specific requirements of the customer. NRG intended to use PALLAS for radio-isotope production, material irradiation test and semiconductor production -- areas where KAERI has experiences in terms of facility design and utilization.

KAERI`s experience obtained from the construction, operation and utilization of HANARO encouraged it to participate in the Dutch bid. Even though KAERI was not chosen as the most competitive bidder, it was a good chance for KAERI and its consortium partners to develop an ability to pursue a foreign research reactor construction project.

KAERI achieved its first small success in exporting research reactor system technology in March 2009. Greece, which has been operating a 5 MW research reactor, opened a bid to upgrade its primary cooling system. The KAERI-KOPEC team participated in the bid and was selected as the contractor.

Meanwhile, in February 2009, the Jordan Atomic Energy Commission invited KAERI to participate in the bidding for a 5 MW multi-purpose research reactor, called the Jordan Research and Training Reactor. On Dec. 3, 2009, the KAERI consortium was selected as the preferred bidder, the first time that Korea won a contract to export a nuclear reactor system.

Last year marked the 50th year since Korea`s first research reactor, KRR-1, was introduced. After half a century of painstaking efforts to master nuclear technology, Korea has finally succeeded in exporting its homegrown nuclear technology. Korea has now established itself as a reactor vendor in the global nuclear market.

Korea has strengths in research reactor supply capability: KAERI has a long history of operating a research reactor and a good track record of developing reactor and utilization facilities. In addition, Korea has strong construction companies and reactor component suppliers. Furthermore, it has a well-established regulatory system and universities that have the infrastructure to foster nuclear manpower.

It is widely accepted that the need for research reactors will increase in the future with the development of biotechnology and nanotechnology. This explains why many countries wish to have up-to-date research reactors, either to replace their old ones as a tool for the development of nuclear technology, or as part of the preparations to introduce a nuclear power reactor.

KAERI will continue to serve for the public by creating valuable scientific achievements and providing indispensable nuclear technologies. The institute is ready to share all of its experience with foreign countries.