KNF obtains a license for its proprietary fuel rod design code

- Its key software technology for the reactor core design code offers opportunities to find channels moving into new markets overseas

KEPCO NF (president & CEO Lee Jae-hee), the one and only nuclear fuel design and manufacturing company in Korea, announced on May 8 that it has been licensed from Nuclear Safety Commission for ROPER code, a fuel rod design code, which finally completed the development project of reactor core design code. The project was designated by the government as a national strategic priority for the development of own nuclear technology and carried out from October 2006 until December 2012 to boost exports in nuclear power-related business.

This newly licensed ROPER developed by KEPCO NF with its own technology is a computation code used for calculating initial conditions of fuel rods in safety analysis for the reactor and as well as evaluating the integrity of fuels rods in use by estimating thermal and mechanical behaviors of the fuel rods during the operation. It already stays one step ahead of the global competition in comparison with other codes imported from nuclear advanced countries through completing verification and application to the latest fuel pellet thermal conductivity model.  

The company earlier developed core design code, which is one of key technologies remained dependent on foreign expertise, and further obtained accreditation and licensing in 2013 for four codes such as two types of nuclear design codes, fuel assembly seismic analysis code, and thermal-hydraulic design code. The ROPER license enabled KEPCO NF to complete the development project of reactor core design codes. The company views that the code will contribute to successful implementation of the second reloading cycle for the APR1400 reactor in Shin-Kori 3 and technology transfer to UAE scheduled for this September.

President Lee Jae-hee stated “A series of success from the development to licensing of KNF’s proprietary nuclear fuels and core design codes proves that now we are fully equipped with patented technologies of nuclear fuel H/W and S/W,” ”this enables us to secure competiveness in international markets and export our products with no restrictions.” 

It is said that the assessment to license ROPER was prolonged by sixteen months from the initial deadline to secure additional database on high burnup fuel performance and development of an uncertainty evaluation method for temperature calculation of nuclear fuel so as to troubleshoot the impact of nuclear fuel pellet thermal conductivity degradation effect due to burnup which was currently raised as an international security issue related to high burnup nuclear fuel.

In October 2009, United States Nuclear Regulatory Commission (NRC) raised a question for the first time about the impact of pellet thermal conductivity degradation effect due to burnup on the safety of nuclear power plants and continued to request major nuclear fuel vendors in October 2012 to submit assessment reports on the issue.

Reactor core design code is a computer program essentially used for nuclear power plant engineering and operation. This is a core technology that major world nuclear energy countries such as US, France would not allow technology assignment to others. From the first operation of nuclear power plant – Kori 1 until now, Korea has paid a huge royalty for the use of design code developed by foreign nuclear power and fuel companies.

It is known that the new codes of KEPCO NF perform more accurate calculation and have better user interface compared to the imported ones used for local reactor core design at the moment. It was possible by applying the latest matrix to the system and KEPCO NF had a key role to develop the codes. Moreover it promoted design efficiency largely by minimizing the number of core design codes about from 350 to 40. 

※ Reference I – [Reactor core design code]

Reactor core design code is a software program that estimates in-pile condition when the uranium inside fuel rods fissions initiated by neutrons. It reads amounts of loaded fuels, locates the loading spot and also shows when to reload. This is a crucial program to produce essential data for safety analysis used for nuclear power plant engineering and operation.

Reactor core design code has been so far resourced from foreign countries with an enormous royalty payment whenever it needed for nuclear power plant construction. This means Korea had barrier in exports of its nuclear power; however with this newly owned technology now Korea views to achieve more exports than ever. There are only two companies in the markets which have their own design codes: WEC of U.S and Areva of France. 

KARMA/ASTRA is a code to read power distribution in reactor, determine safe and efficient fuel loading spot and perform safety analysis, fuel rod integrity test and relevant data output used for plant operation. DYTRAC is a computation code used for fuel safety analysis in case of earthquake. THALES is another computation code that analyses thermal hydraulic behavior.

※ Reference II – [ROPER computation code]

Fuel rods are supposed to experience thermal and mechanical fatigue either during operation or under reactor accident conditions, yet should maintain the integrity.

ROPER computation code is developed by KNF using its own technology to assess the integrity of the fuel rods during operation and under reactor accident conditions. KNF focused on the development of performance model to simulate the thermal and mechanical process that fuel rods may experience during the operation and successfully led to computerizing it into a code. It can be diversely applied to WEC-type, Korean standard type, and APR1400 nuclear power plants as the company completed development and verification of design methodologies considering multiple operational conditions and also aiming at design and material properties of fuel rods.