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发表于 2017-4-19 11:24
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来自: 中国辽宁沈阳
Nuclear Merchant Ships - Fall
Attempts have been made in the past to development nuclear merchant ships, but these projects have failed for technical, economic, or political reasons. The U.S.-built NS Savannah and the German-built Otto Hahn were decommissioned because they were too expensive to operate, partly due to safety concerns and insurance issues involving the use of nuclear power in civilian ports. The Japanese Mutsu was dogged by technical and political problems.
It was essential to establish the marine plant with excellent safety and reliability which is capable of competing with the conventional ships in economy, and being accepted by the people and the international society in order to be prepared for the practical application of the future nuclear powered ship. For this purpose, it is important not only the demonstration by the model or test device to simulate the actual condition, but also the establishment of various environment necessary for the operation of the nuclear powered ship such as the establishment of the safety standards which are operationally and internationally common as the ship.
Development of operation support system such as automatic operating system and anomaly diagnosis systems of nuclear reactor is very important in practical nuclear ship because of a limited number of operators and severe conditions in which receiving support from others in a case of accident is very difficult. The goal of development of the operation support systems is to realize the perfect automatic control system in a series of normal operation from the reactor start-up to the shutdown.
By 1980 some shipbuilding authorities and ship fleet owners were predicting that nuclear powered merchant ships will be sailing the high seas before the end of the century. In that only a few private shipyards in the United States have had the opportunity to construct and repair nuclear powered ships, the other private shipyards must be made aware of what is involved if they are to meet the challenge of nuclear shipwork. If the builder of a nuclear powered merchant ship is acting as the agent for the prospective shipowner-operator and is responsible for the entire design and construction of the ship, he would need designers who are knowledgeable of nuclear ship construction and highly skilled craftsmen. He would also need an enlarged workforce that would possibly include a legal staff, extra security guards and clerical help and other support personnel plus special tools for the nuclear work. If, on the other hand, the ship's nuclear system is the entire responsibility of a vendor, the shipbuilder's needs could be less, possibly about the same as that needed for conventional shipwork.
A detailed and comprehensive Code of Safety for Nuclear Merchant Ships was adopted by the IMO (International Maritime Organization) Assembly in 1981. The International Convention for the Safety of Life at Sea (SOLAS) [the SOLAS Convention] in its successive forms is generally regarded as the most important of all international treaties concerning the safety of merchant ships. The 1974 Convention has been updated and amended on numerous occasions. Chapter VIII "Nuclear ships" gives basic requirements for nuclear-powered ships and is particularly concerned with radiation hazards. It refers to the detailed and comprehensive Code of Safety for Nuclear Merchant Ships which was adopted by the IMO Assembly in 1981.
Chapter VIII is supplemented by the Code of Safety for Nuclear Merchant Ships and the Safety Recommendations on the Use of Ports by Nuclear Merchant Ships. In view of the risk posed by nuclear merchant ships, SOLAS regulation VIII/11 introduces special control measures. In addition to the general powers of control conferred upon port States by regulation I/19, regulation VIII/11 provides that nuclear ships "shall be subject to special control before entering the ports and in the ports of Contracting Governments, directed towards verifying that there is on board a valid Nuclear Ship Safety Certificate and that there are no unreasonable radiation or other hazards at sea or in port, to the crew, passengers or public, or to the waterways or food or water resources". Accordingly, port States are authorized to enforce control measures in respect of foreign vessels in innocent passage through the territorial sea provided these vessels have clearly shown their intention to enter port.
The marine reactor as a main engine for general merchant ships is difficult to be used due to limitation of the port of cal1. However it is expected to greatly contribute to the advanced marine transportation, ocean development, etc. when the base for putting the reactor into practice is prepared. The design, evaluation and research of the improved marine reactor which is more miniature and lightweight and highly safe compared with the existing design are continuously conducted in Japan since 1983 in order to obtain the concept of the reactor which is suitable to the required perform-ance and limitation condition corresponding to use of the future rnarine reactor.
Nuclear power may have proved enormously effective for warships, requiring refuelling only once at the mid-life of a submarine or aircraft carrier, but experience with the experimental merchant ships failed to demonstrate that such vessels could be commercially viable. First costs were very high, in comparison with a diesel-driven or steam turbine propelled vessel. The importance of nuclear safety was clearly enormous, and the costs of nuclear trained specialist engineers were found to be prohibitive. Perhaps as important were the reactions from many members of the public, who were understandably nervous at the prospect of nuclear-powered merchant ships entering their ports.
The Japanese nuclear ship Mutsu was blockaded by her country's fishermen, and she was eventually demolished. Otto Hahn was re-engined to become a containership, and Savannah, her reactor removed, went into long-term layup.
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