[en] This paper will address the lessons learned during the implementation of International Atomic Energy Agency (IAEA) safeguards at the Rokkasho Reprocessing Plant (RRP) which are relevant to the issue of 'safeguards by design'. However, those lessons are a result of a cumulative history of international safeguards experiences starting with the West Valley reprocessing plant in 1969, continuing with the Barnwell plant, and then with the implementation of international safeguards at WAK in Germany and TRP in Japan. The design and implementation of safeguards at RRP in Japan is the latest and most challenging that the IAEA has faced. This paper will discuss the work leading up to the development of a safeguards approach, the design and operating features that were introduced to improve or aid in implementing the safeguards approach, and the resulting recommendations for future facilities. It will provide an overview of how 'safeguardability' was introduced into RRP.

[en] JNFL have been conducting Active Test with spent fuels at Rokkasho Reprocessing Plant (RRP). In Active Test, the evaluation of radioactivity release to the environment (atmosphere and sea) was obtained. (authors)

[en] The IAEA has never before been experienced with designing a credible safeguards approach for a large scale reprocessing plant. The safeguards discussion was initiated in 1988, but at that time no available model or guideline that could be used as a reference. The IAEA, the State and JNFL have studied and discussed the safeguards approach and safeguards system, and established effective, efficient and credible safeguards for RRP, under extensive cooperation manner. This paper presents overview of the safeguards system at RRP from the operator's viewpoint. (author)

[en] The Analysis Facility of Rokkasho Reprocessing Plant (RRP) has a unit which recovers plutonium from the analytical liquid wastes. From September 2012 to May 2013, we operated 11 batches with this 'Plutonium Extraction Unit'. The operations were successfully completed although the concentration of analytical reagents like sulphate ion in the analytical liquid wastes was higher than design. In this paper, we evaluate and describe the result of the operations. (author)

[en] The On-Site Laboratory (OSL) is committed to providing the IAEA with reliable, accurate and timely results of the inspection samples taken at the Rokkasho Reprocessing Plant (RRP). The OSL is an important part of the efforts to safeguard adequately this large reprocessing plant. It is located on the premises of the RRP, which helps to resolve the timeliness dilemma. The OSL is operated jointly by the IAEA, the Nuclear Material Control Center (NMCC) and Japan Safeguards Office (JSGO). This joint task requires addressing new challenges in destructive analysis (DA) and the sharing of instruments, space and procedures in order to reach the best analytical results possible. The inspector-analysts make great efforts to achieve excellence in the sample chemistry and to ensure that the procedures and results are adequately authenticated. Because the instruments are jointly used, new approaches for the implementation of measures for authentication and continuity of knowledge have been designed and put into practice. The authentication measures include securing the instruments and the data produced. Additionally, special attention is given to maintaining continuity of knowledge of the samples that undergo chemical analyses, securing the procedures and considering measures of deterrence. All these measures build a relatively solid framework for independent DA. It must be understood that a 100% assurance for a tamper-free operation is a great challenge, and the IAEA aims to achieve the best authentication under the given situation. The implementation of authentication in the routine sample chemistry requires additional efforts on the part of the IAEA and has an impact on the time needed to perform the work, compared to the activities of a normal nuclear laboratory. This paper describes the authentication policy in the OSL, the specific measures implemented and the range of confidence expected in different procedures. (author)

[en] During the first step, the second and the third step of Active Test (AT) at Rokkasho Reprocessing Plant (RRP), the performances of the Head-end Facility were checked, mainly for shearing and dissolution: shearing force and shearing time were the values as expected and concentration of U and Pu in dissolution solution were the values as expected. And safety requirement for acidity in dissolution solution was satisfied. (authors)

[en] Burnup credit is taken in criticality safety control at the Spent Fuel Storage Facility (SFSF) and at the Fuel Dissolution Facility in the Rokkasho Reprocessing Plant. Spent fuel burnup value is measured using a burnup monitor at the SFSF. Storage rack types are selected with U²³⁵ residual enrichment derived from initial enrichment and measured average burnup value. At the Fuel Dissolution Facility, the necessity of neutron absorbers for nitrate solutions are judged based on initial enrichment and top 50 cm average burnup values. The burnup monitor was calibrated against operator declared burnup values through measurements of 100 spent fuel assemblies. The monitor has measured about 10 thousands spent fuel assemblies during these 10 years and operation is steady. The burnup monitor consists of two Ge detectors for gamma spectrometry, four fission counters for passive neutron counting and twenty ion chambers for relative burnup profile measurement on each opposite side of an assembly. The burnup monitor has under water driving units for fuel elevation, centering fuel position and setting fission counters on the surface of the fuel assembly. Presently, an improved type of burnup monitor is being developed for the purpose of reducing waste and exposure during maintenance work. The improved equipment has a few ion chambers at the top region only. They measure the axial profile of gross gamma-ray intensity while inserting an assembly into the equipment. The fuel elevating driver will be reduced. Fission counter driving units serve as fuel centering guides. The fuel scanning system determines effective fuel regions using depressions that appear at the position of spacers or grids in a measured profile. Thus, average burnup measurement is performed independently from the information relating to the position of the fuel handling machine. Moreover, some additional self diagnostic functions will be applied for gross gamma-ray scanning measurement. This includes for example, the checking of signal noise and fuel swinging during measurements. (authors)

[en] Full text: Accurate determinations of volume are a fundamental component of the accountancy of nuclear material (NM) in a facility that processes such material in liquid form. In the Rokkasho-mura Reprocessing Plant (RRP), the inlet accountancy is performed in a tank (IAT) that has been initially calibrated during the cold tests in 2002. To ensure that the calibration curve V = f(H) is remaining valid during the whole life of the plant, the operator performs a specific test once a year during a long time shutdown. This test consists in pouring known amounts of water in the tank and measuring the resulting height of liquid with the dip tubes (fast bubbling rate). The IAEA is measuring independently the levels and densities in the tank using its own manometers, part of the SMMS-1 system. The temperature and mass values are operators data. During the test, inspectors randomly survey the data collected by the operator. Samples are taken in the tank before and after calibration, and also in the feeding tank. These samples are independently measured in the OSL. In order to limit the errors, the procedure and conditions of the calibration check are very close to the ones of the initial calibration. Yet some differences cannot be avoided, such as the presence of the heel in the bottom in the tank, the presence of a hydraulic seal on the feeding line, the operation of the ventilation off gas system, the use of humidified bubbling air, and so on. The evaluation of the calibration check results by the IAEA must take into account all the possible errors or biases in order to detect any significant change in the way volumes are measured in this tank. Many technical issues are discussed internally (SGOA2, PSA) and with the operator during technical meetings. (author)

[en] Japan has established the commercial nuclear fuel cycle with LWR as a non-weapon state (NWS), and now has been developing FR fuel cycle as the next generation technology. The Government of Japan intended to start the discussion in 2010 on the second reprocessing plant next to Rokkasho Reprocessing Plant (RRP) in the 'Framework for Nuclear Energy Policy', October 2005. 'Five Party Council' has established a working group for the preparations toward the national discussion on the second reprocessing plant, and will submit the report in December 2008. It will be the transition period from LWR cycle to FBR cycle, therefore, the reprocessing plant may be required to receive the spent fuels from both LWR and FBR. The challenges in the aspect of nuclear nonproliferation will be complex depending on what technologies will be adapted, how it will be developed, and its R and D schedule. JAEA is expected to continue being responsible on the R and D including nonproliferation technologies. The key is the close communication between the designers of the nuclear energy system and the process, and nonproliferation analysts including safeguards and proliferation resistance. In this regard, the four key areas, which are critical in order to acquire the international acceptance and are needed to work together with the designers and nonproliferation experts, are identified. They are 1) Technology that enhances proliferation resistance, 2) Advanced safeguards technology, 3) Development of proliferation resistance evaluation methodology, and 4) Nuclear security and physical protection technology. They are all needed to be developed on the international consensus basis. This paper presents 1) Japanese R and D programs for future nuclear energy system including the transition period, 2) Four key areas of nuclear nonproliferation, 3) JAEA's efforts for the establishment of international consensus. (authors)

[en] The Rokkasho Reprocessing Plant is owned and operated by Japan Nuclear Fuel Limited (JNFL). The main part ol the plant is based on AREVA process used in French reprocessing plants La Hague. The plant originally planned to put into operation in 1995, but the problems constantly emerge during construction and test phases. In January 2016, JNFL announced to change the work plan, pushing back the scheduled completion date to September 2018. The date for completion of construction and testing of the plant has been postponed for the 23 th time. This paper will review construction process of the Rokkasho Reprocessing Plant, and study the experiences and lessons. (authors)