Spent fuel transportation by sea
M.V.Baryshnikov, A.V.Khudyakov (Sosny R&D Company) V.M.Ovsyannikov (ASPOL Baltic Concern), V.I.Shlyachkov (Krylov Shipbuilding Research Institute)
Nuclear & Enviromental Safety, №1, 2010
Foreign companies have gained a lot of experience of rine transportation of spent nuclear fuel. Use of sea tran port in our country could help resolve the issue of spentfu transfer from the northern naval bases and power plants, well significantly simplify delivery of spent fuel from cou tries that do not share a common border with Russia.
LEGISLATIVE AND REGULATORY SUPPORT
Transport of spent fuel by sea must meet the requirements of the internationally-recognised safety provisions for transport of radioactive materials, as well as the nation codes and regulations of the exporter country, the count of destination, the country whose flag the transport ship carries, and the countries whose ports the ship enters. Such international rules are set forth in the IAEA Regulations fo the Safe Transport of Radioactive Material (TS-R-1, 2005).
Such transport is regulated mainly by maritime legislation. Any vessel is obliged to comply with the requirements of the. regulations issued by the International Maritime Organisation (IMO). These primarily include the International Convention for the Safety of Life at Sea (SOLAS-74), which sets the minimum safety standards for building, equipment and operation of sea vessels, covering floodability, stability, mechanical and power sections of the vessel, provisions for fire safety, rescue, radio communications and safe navigation. Other such regulations include the International Convention for the Prevention of Pollution From Ships MARPOL-73/78, the International Maritime Dangerous Goods Code (IMDG Code), the International Ship and Port Facility Security Code (ISPS Code), the International Standard for the Safe Operation of ships and for Pollution Prevention.
The International Code for the Safe Carriage of Irradiated Nuclear Fuel, Plutonium and High Level Radioactive Wastes in Flasks on Board Ships International (Irradiated Nuclear Fuel - INF Code) determines that there are three categories of vessels that transport spent fuel, depending on the total radioactivity of the cargo:
- Class INF-1 – Ships which are certified to carry INF cargo with an aggregate activity less than 4,000 TBq (4* 1015 Bq).
- Class INF-2 – Ships which are certified to carry irradiated nuclear fuel or high-level radioactive wastes with an aggregate activity less than 2*106 TBq (2*1018 Bq), and ships which are certified to carry plutonium with an aggregate activity less than 2*105 TBq (2*1017 Bq).
- Class INF-3 – Ships which are certified to carry irradi¬ated nuclear fuel or high-level radioactive wastes and ships which are certified to carry plutonium with no restriction of the maximum aggregate activity of the materials.
The Irradiated Fuel Code obliges the ship owner to obtain an international certificate of conformance for the vessel used for transports of dangerous loads and have the ship certified and recertified for compliance as per the provisions of SOLAS-74. The Russian safety code for transportation of radioactive materials (NP-053-04) is based on the IAEA standards and corresponds to their provisions. The code that regulates entry to / exit from ports of the Russian Federation of ves¬sels carrying nuclear materials and radioactive substances (R 31.2.12-04) produced by the Federal Agency of Sea and River Transport of the Russian Federation (Rosmorrechflot) provides the main requirements for all organisations that take part in maritime transportation of class 7 dangerous cargoes (which includes spent fuel and radwaste), and a list of documentation that must be in possession of any Russian shipping company that participates in the transportation of nuclear materials and radioactive substances. The certificate that authorises sea transport of spent fuel by a vessel is issued by the Head Department of the Russian Marine Registry of Shipping (Saint Petersburg).
FIRST TRANSPORT OF SPENT FUEL BY SEA IN RUSSIA
Until recently, there were no certified sea transports of spent fuel in Russia. The Government of the Russian Federation authorised 14 Russian sea ports to engage in operations involving class 7 dangerous cargoes. However, the actual ability to accept ves¬sels carrying cargoes of spent fuel also depends on a number of other circumstances, amongst which are the port's possession of a licence to handle class 7 dangerous cargoes issued by Rostekhnadzor, concurrence of the local authorities with the acceptance of the cargo, etc. All these requirements are observed only by the Murmansk Sea Port, on the condition that the spent fuel cargo is loaded/off-loaded by FSUE Atomflot.
Theoretically, any Russian or foreign company can perform sea transports of spent fuel in Russia, as long as it is licensed by Rostekhnadzor to engage in such activities. However, it is not easy even for Russian companies to observe these requirements. For example, the captain of the vessel must possess a Russian-issued permit for involvement in nuclear power operations, the carrier vessel must meet the Russian sanitary and epidemiology norms. The procedures for distribution and transfer of responsibility for physical protection of the spent fuel cargo must be approved by the Rosatom Corporation.
The first Russian sea transport of spent fuel took place in September 1998. The Kandalaksha motor boat carried from Dudinka to Murmansk the spent fuel assemblies from the Norilsk nuclear reactor using specialised transport overpacks TUK-19. The earner ship was not certified to any of the INF classes.
In 2000, the Yuzhny Sevastopol shipyard used a VNIPIET design to upgrade the Fili dry cargo vessel to meet the requirements for transport of class 7 dangerous cargoes. It was expected to carry fresh fuel in the TK-S4 и TK-S5 casks, and spent fuel in TUK-13 transport over-packs, for which purpose the ship's hold was re-fitted to ac¬commodate special cradles. The vessel made several Izmaii - Taganrog - Izmaii trips to deliver fresh nuclear fuel for the Kozloduy Plant in Bulgaria, but still failed to obtain an international INF certificate.
In September-October 2008, under the Repatriation Programme for spent fuel from Russian-made research reac¬tors, a one-off spent fuel transport trip was made from Koper, Slovenia, to Murmansk. The spent fuel from the Institute of Nuclear Research of the Academy of Science of Hungary was packaged into the SKODA VPVR/M transport over-packs, which were in turn secured inside reinforced 20-foot ISO containers. The fuel was transported by the Lynx motor ship (run by Edlow International of the United States) specifically fitted for transport of spent fuel (class INF-1 and INF-2 international certificate). Nonetheless, the Lynx had great difficulty reaching Murmansk (the voyage 4,500 nautical miles long took 24 days) as it was ill-prepared for navigation in the northern seas.
That trip was an exceptional case when a foreign vessel was al lowed to enter the territory of FSU E Atomflot. It only became possible because the responsibility for the spent fuel cargo before Russian laws was assumed by a Russian carrier. ASPOL Baltic Concern, which is licensed by Rostekhnadzor for marine transports of dangerous cargoes, contracted Lynx for the trip and received authorisation for this one-off transport of spent fuel. The supervisor captain that was placed on the ship by ASPOL Baltic Concern was personally responsible for the cargo and had all the necessary permits for involvement in nuclear operations.
DOMESTIC-MADE CLASS INF-2 VESSEL
The experience that was obtained by Russian companies as a result of first practical transports of spent fuel by sea has demonstrated that it is possible and essential for Russia to create its own class INF-2 vessel. The function of Client for this vessel is being performed by the Repatriation Programme for spent fuel from Russian-made research reactors.
In 2008, the firm Sosny of Moscow developed a technical specification for re-fitting a motor ship operated by ASPOL Baltic Concern of Saint Petersburg to make it suitable for transport of spent fuel and preparation of the appropriate detailed design documentation. The design development was contracted to the leading Russian science and technology centre for ship-building and watercraft - the Krylov Shipbuilding Research Institute (Saint Petersburg).
During the development process, limitations were iden¬tified for permissible releases and discharges, levels of radia¬tion in on-board rooms and on external surfaces of the vessel body, additional protection measures for the crew, including calculations to determine the thickness of additional shield¬ing for the cargo hold, list of potential accidents. Evaluations were made of the potential consequences of accidents (along with recommendations for radiation protection of crew members) and their impact upon the environment. In ad¬dition to that, also developed and accepted by the Russian Marine Registry of Shipping was the set of key operational documents, which included information about the vessel's stability, cargo loading and securing instructions.
The re-fitting of the vessel was carried out in June-August 2009. As a result, ship stability in a damaged condition and its floodability became compliant with part B-l of chapter II-l of the SOLAS-74 convention (resolution MSC/19(58)). Structural strength of the decks, cask securing supports and hold bottom are now in line with the requirements associated with the transport of 15 ISO-containers each weighing up to 31 tonnes, with two-tier arrangement possible.
The cargo space is separated by a cofferdam with the whole lateral bulkheads 10-12 mm thick, which, if completely flooded with outside water, may act as biological shielding (in that case it becomes an additional ballast tank with the volume of about 60 m3). Near the cofferdam there are shafts for emergency ex from the cargo space.
The cargo space thus consists of two separate holds. On the fore hold (hold No. 1) is designed to contain class INF-2 cargoes as it is the farthest from the crew accommodation superstructure; this hold was fitted to meet the requirements of the Spent Fuel Code.
Separate drainage is provided for the fore hold (No. l), the after hold (No. 2) and the cofferdam. The electric motor of the drainage pump is powered from the emergency switchboard. The deck of the fore cargo hold is equipped with special seats that are made flush with the flooring. The fastening of the cask does not provide for any rope or chain lashing or tam-buckling so as to minimise the time spent by people in the hold during the fastening and unfastening of the cargo. For the purposes of provision of additional shielding for the crew, the casks containing spent fuel are covered with a special composite screen made of a concrete slab 200 mm thick lined on both sides with 10 mm thick plates of steel.
Using a set of ID and FD fans, the ventilation system of the cargo hold is divided into two systems of forced exhaust ventilation: one for the fore hold, another for the after hold (at any time, ambient temperature in either of these will not exceed 55°C).
The system of carbon-dioxide fire extinguishing is also split into two parts; the number of carbon-dioxide bottles in each corresponds to the new volumes of the cargo spaces (hold No.1 - 2,200 m3; hold No.2 - 2,400 m3). Also installed in the holds are additional CO2 release jets and additional piping.
The vessel is equipped with additional electrical equipment, in particular, a system for emergency lighting of the exits from the holds, a system for control of ventilation the on-board cofferdam, alarms to signal water ingress into the holds, a system for remote shut-down of hold fans when CO2 starts releasing. Provided for the fore hold separately are a ventilation control system (for automatic start of the back-up fan in case of main fan failure), control of the additional draining pump, CO2 release alarm and fire alarm.
Additional physical barriers prevent unauthorisd access of intruding trespassers into the cargo rooms. The vessel is also equipped with intrusion detection and surveillance equipment and intrusion alarms. The re-fitted motor ship has obtained the international certificate of conformity for transport of spent nuclear fuel (INF-2 certificate). The conditions of the licence issued to ASPOL Baltic Concern have been amended to include transportation of packages containing spent nuclear fuel.
In September 2009, within the framework of the Repatriation Programme for spent fuel from Russian-made research reactors, spent fuel from the Polish Eva reactor, packaged into 16 SKODA VPVR/M overpacks, which, in turn, were placed inside eight 20-foot ISO-containers, was successfully delivered from the port of Gdynia to Murmansk by the Russian class INF-2 vessel.
Количество просмотров: 523