ASSESSMENT OF TRANSPORT OF IRRADIATED NUCLEAR FUEL

There are more than 40 reactor units in operation at 15 sites in Russia (9), Ukraine (5) and Kazakhstan (1), and the spent fuel policy (reprocessing, away from site storage or on-site storage) and the transportation of irradiated nuclear fuel represents an important part within the nuclear fuel cycle of each country. The transport of irradiated nuclear fuel to the reprocessing plant, or to the fuel storage facility is of special importance because of the adherence to the safety requirements that must prevail during the operations. These safety requirements have to ensure the same level of protection for the workers, the environment and the public, regardless of the transport mode selected.

The objective of the project was to assess and evaluate the current way of the transportation of irradiated nuclear fuel (INF) in the New Independent States (NIS): Russia, Ukraine and Kazakhstan and to compare the situation with the international standards, International Atomic Energy Agency (IAEA) recommendations and western practices.

The aspects covered include the design, fabrication and maintenance of packaging; the preparation, consigning, handling, carriage, storage in transit and receipt at the final destination; as well as the quality control, quality assurance, and compliance assurance. They include normal and accident conditions in carriage and in storage during transit.

The specific objective was to provide the beneficiary with the contractor’s expertise in the safety, technological and managerial aspects of INF transportation in and outside the nuclear power plants (NPP) and in storage and reprocessing facilities, taking into account the railway mode of transport.

The project activities commenced in September 1995 and finished in December 1997. They were organized in the following tasks:

Task 1. Assessment of the global transport plan.

The global transport plan in the NIS countries contains a general description of the existing transports of spent fuel within Russia, Ukraine and Kazakhstan as well as between these countries and between foreign countries and Russia.

Spent fuel transportation on a regular basis from Russian and Ukrainian nuclear power plants started in 1974, and the number of shipments increased to a peak in the 80s. After the collapse of the Soviet Union in the early 90s, this activity declined, in particular, the transportation between different countries.

Transportation of the spent nuclear fuel in the NIS countries is based on the principles and equipment elaborated or designed and used in the former Soviet Union. All spent fuel is transported by train.
Most of the former regulations remain valid although they have been renamed or modified. Russia, Ukraine and Kazakhstan have based their transport operations on the International Atomic Energy Agency (IAEA) recommendations. These countries also rely on international standards from the International Commission on Radiological Protection (ICPR) and International Standardization Organization (ISO).

The spent fuel management strategy depends on the reactor type: RBMK and GLWR fuel is stored on site. Because many RBMK pools are close to their maximum capacity, reracking and building of additional storage areas is currently taking place. VVER-440 and BN fuel are sent for reprocessing to Chelyabinsk, and VVER-1000 fuel is stored away from site, in Krasnoyarsk.

Task 2. Assessment of the package.

The systematic evaluation of the packages used in the NIS countries with regard to international standards, IAEA recommendations and western practices yielded the following conclusions and recommendations:

• Regulations in partner countries and EU are principally equivalent
• Certificate of approval: precise instructions for pre-shipment control, maintenance and retesting should be added, but such instructions are in other regulatory documents, which are obligatory for NPP.
• All the technical notes, which currently exist, should be gathered in a comprehensive safety analysis report, in conformance with international practices. The safety analysis report should reflect how the package design and operation protects the public, property and environment from the effects of radiation during transport of radioactive material, by demonstrating a compliance with the containment of radioactivity, the control of external radiation levels, the prevention of criticality, and the prevention of damage caused by heat.
• The design of the existing transport casks should be modified by adding shock absorbing and heat insulating structures.
• To compensate the use of non resilient steels at low temperature, emphasis should be put on ensuring conservative decay heat calculations, adequate maintenance of the heaters in the railcar, and training of staff.
• More drastic Inspection plans should be prepared and implemented because current inspection periods are far from the western practices.
• For VVER 440 type reactors, a new cask design should be developed incorporating a cask body with good low temperature ductility (special forged steel, austenitic steel); double o-ring seals with the test penetrations; protection of the lid area and the bottom to withstand drop and fire, neutron shielding and gas as the primary coolant of the INF.

Additionally under this task, the contractor has drafted guidelines for the design and licensing of a package.

Task 3. Fuel handling, and Task 6, section transport organization and management
Transport administration, spent fuel handling and cask loading are very closely related and can be considered as a continuous activity.

In general, fuel handling (which includes fuel acceptance, fuel integrity checking, fuel identification, fuel compliance with the package design approval, loading in a cask and cask preparation to transport) appears to be well managed, complete and in compliance with western practices. However, the numerous individual and isolated technical and operational instructions for each of the activities should be completed by an organized formal document structure (to comply with common international practices) linking all spent fuel handling, transport administration and management activities.

It is also requested that the consignor or user shall be prepared to provide the capability for competent authority inspection during use.

Several actions for improvement have been identified:

• Development of the control systems to guarantee through independent checking that input data to the computer programme that demonstrates design safety requirements, is correct,
• Development of document control to certify that the fuel assemblies have been checked and approved against safety related parameters of the design safety report and the package approval certificate.
• Development of means to check for fuel element identification.
• Provide means to measure temperature and gamma dose rates of TK10 cask at Krasnoyarsk RT2.. (in the long term, line temperature and gamma dose rate sensors and written records should be developed)
• Monitor dose rates during the transfer operations with cask TK6, and modify the operations to minimize contamination and individual exposure (in the long term, a redesign of the transfer cylinder should be considered)
• Packagings should be periodically inspected, maintained and repaired (if needed), by developing a controlled record of movements of the casks and wagons available at the site draft of inspection and repair procedures for the wagons and certificates of attendance and identification of the frequency for the maintenance of the wagons.
• Development of a radiation protection programme (task 4)
• Development of an inspection programme.
• The fuel management in Aktau BN 350 is questionable and has a potential danger.

Task 3 also proposed a detailed transport procedure and transport quality plan linking all the activities, and identifying check list, document control, interfaces and responsibilities for the complete cycle, as well as a transport file to accompany the cask and wagon through its complete cycle of operation that will allow for continuous control and provide an auditable account of compliance.

Task 4. Radiation protection.

This task identified the following actions for improvement:

• to perform non-fixed contamination measurement for alpha, beta and gamma emitters. The units should be Bq/cm2. Fixed contamination measurements are not recommended and are not useful because they are also performed by dose rate measurements.
• to prepare a radioprotection programme, which should identify the risks of radiation and/or contamination hazards, the precautions to take, the type of measurements, the equipment to be used, the description of the responsibilities to take the measurements, the procedure to record and report them, the limits, the corrective actions in case the limits are exceeded, etc.

Task 4 proposed detailed guidelines to draft a radioprotection programme, focused on recommendations for measurement (type of measurement: contamination or dose rate, equipment to be used (calibration, qualification of personnel, verification), definition of the measuring points, records, limits, precautionary, corrective or contingency actions and documentation.

Task 5. Quality assurance.

A sound quality assurance system demonstrates that all relevant aspects of the radioactive material transport operations are clearly identified, controlled and documented, which in turn helps to ensure the safety of the public, property or the environment. Organizations and public bodies such as consignors, railway transporters, health physicists, consignees and manufacturers should develop, implement and maintain a quality assurance system for all their activities related to the transport of radioactive material, (specially spent fuel) in order that the competent authority is able to ensure compliance with the regulations.

Task 5 defined the requirements to a sound quality assurance system, like the need of common basic criteria (i.e. ISO 9001 standard), contractual links between organizations, identified and controlled interfaces, common operating procedures for equipment design and maintenance, package identification, handling and shipment, emergency responses, and common dispositions for review by the competent authority.

This task established in detail the method to develop a relevant and coherent quality assurance system:

• Definition of the quality assurance as a systematic programme of controls and inspections applied by every organization or body involved in the transport of radioactive material aimed at providing adequate confidence that the standard, prescribed in the regulations, is achieved in practice..
• Basis of the quality assurance, which states that a quality assurance system is to be prepared and implemented in each organization involved in the different activities related to the transport of radioactive material.
• Contents of the quality assurance system describe what should be incorporated in the system, such as the quality assurance manual, the basic procedures, operating instructions and records and quality assurance lifetime records.
• Quality assurance manual, to cover the whole range of activities related to radioactive material transport. It should be developed for each organization and describes the organization; the quality system; contract review and project organization; design and document control; purchasing; client supplied products; process control; inspection and testing; identification and traceability; discrepancies, non conformities; corrective and preventive actions; radiation protection; etc.

The integration of all the activities associated with cask design, licensing and manufacturing, with cask handling, fuel acceptance, transport and maintenance of equipment can be addressed in the quality assurance system, explained briefly in the quality assurance manual, but developed with detail in the specific transport quality procedures.

Task 6 has already been summarized under Task 3 above.

Task 7. Emergency response.

Task 7 objective was to propose basic guidelines to prepare emergency response statutory documentation and to rebuild the emergency response planning, using equivalent emergency response organization and planning of France and UK.

Task 7 describes the French and English emergency response systems and suggests the following proposals to improve the existing emergency planning in the NIS

• Determining the broad scale and characteristics of the various potential hazards that could occur and the actions necessary to provide effective mitigating action. To perform this subtask, a study of the cask types behaviour and performance in beyond design basis accident must be carried out in advance.
• Identification of national resources available to respond and undertake effective countermeasures. A survey of industrial and governmental agencies will be required to determine the available resources, which could be required to pool into a common plan.
• Defining the interface between national and local authorities, involving both technical and political inputs.
• Strategic planning
• Implementation
• Training and drills

RECOMMENDED MEASUREMENT IMPLEMENTATION PLAN.

The EU experts, in close cooperation with the NIS specialists drafted a set of proposals and recommendations to improve the present situation of spent fuel transportation in the three NIS. A brief description of the actions as well as a proposal of the composition and functions of the administrative committee for the implementation and follow-up of the actions is also outlined as an outcome of the project. A brief summary of the proposals, time schedule for implementation and tentative budget is presented below.

Proposal 1. Regulations

To offer (to the competent authorities of the three NIS countries) recommendations, advice and expertise of EU specialists to ensure that the national regulations and standards comply with the international practice. This proposal is specific for each country and a time schedule cannot be suggested. The assistance budget equals 15 man-days of senior EU experts (for each country)

Proposal 2. Cask modification package

The proposal consists in modifying existing casks by adding shock absorbers and insulation, and in evaluating the feasibility of a new design.
The overall time schedule is 10 months, and the budget is 50 man-days of senior NIS experts, 20 man-days of junior NIS experts and 5 man-days of senior EU experts.
The time schedule for the feasibility study is 3 months and the budget is 30 man-days of senior NIS experts.

Proposal 3. Design of a new cask to replace TK6.

The overall time schedule is 18 months:
The budget is 400 man-days of senior NIS experts, 100 man-days of junior NIS experts, and 20 man-days of senior EU experts.

Proposal 4. Design and manufacture a new spent fuel transfer cylinder, including a feasibility study, inventory of sites and needs, assessment of risks, alternatives, cost and schedule evaluation and comparison.

The overall time schedule is 13 months. The budget is 80 man-days of senior NIS experts, 20 man-days of junior NIS experts, and 10 man-days of senior UE experts. The time schedule for the feasibility study is 2 months, and the budget is 20 man-days senior NIS experts.
Proposal 5. Develop a complete quality assurance system in each of the countries, plus the organization of a seminar to train and indoctrinate NIS specialists.

The time schedule is 13 months for each country, and the budget is 300 man-days of senior NIS experts, 100 man-days of junior NIS experts, and 100 man-days of senior EU experts. The seminar takes 1 week and the budget is 25 man-days of senior NIS experts and western consultancy.
Proposal 6. Development of an emergency response programme, including the identification of hazards, physical and human resources, organizations, responsibilities and interfaces as well as drafting the emergency response plan.

The time schedule for each country is 12 months, and the budget is 500 man-days of senior NIS experts, 100 man-days of senior EU experts, and 100 junior NIS experts.
Proposal 7. Inspection and test after loading, including the preparation of inspection procedures, design and engineering work of the hardware necessary for their implementation (vacuum drying, leak tests, gas sampling, etc).

The time schedule is 9 months, and the budget is 110 man-days of senior NIS experts, 20 man-days senior EU experts.

Proposal 8. Design and manufacture of transport capsules for leaking BN 350 fuel assemblies. The time schedule is 6 months and the budget is 30 man-days of senior NIS experts.