Lloyd's Register: Lloyd's Register explores the reintroduction of nuclear propulsion for merchant ships

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Research is focused on the application of nuclear propulsion to tankers, bulk carriers, container ships and cruise ships
Dec 10, 2009 (M2 PRESSWIRE via COMTEX) --


Early in 2007, Lloyd's Register began research into the implications of nuclear propulsion for merchant ships.

This initiative was built on Lloyd's Register's extensive experience in the traditional nuclear industries and from studies which led to the formation of its Rules for the Nuclear Propulsion of Ships.

The Rules, available from 1966 until 1976, were developed in response to the interest shown in nuclear propulsion in the early 1960s, which resulted in ships such as Savannah, and Otto Hahn, two ships that were technically successful.

At that time, operational and economic conditions were not conducive to commercial success of nuclear propulsion. But both ships, nevertheless, traded worldwide for some years.

Over the years, there has been a steady, slow development of nuclear propulsion for merchant ships -- principally with ice breakers -- but also extending to a lash barge carrier and a containership.

Indeed, two nuclear ice breakers presently are utilised on popular passenger cruises.

The steady increase in the price of fuel oil -- and the probable introduction of either a carbon-emissions trading scheme or a related tax -- now presents the possibility that nuclear propulsion could be more competitive.

Lloyd's Register's research programme is revisiting the technical challenges of nuclear propulsion for ships, as well as refuelling and waste-disposal issues.

The scope of the programme has been expanded to include public health, manning, training, operational, risk and regulatory requirements. The principle maritime sectors of focus are how these propulsion systems could benefit tankers, bulk carriers, container ships and cruise ships, although a range of other ship types may also benefit.

"The technology is there to commence building nuclear ships. The issues regarding their acceptability and the need for a cultural step-change in shipping still need to be addressed so that society is comfortable any risk is being managed", commented John Carlton, Global Head, Marine Technology & Investigations, Lloyd's Register.

Most nuclear-powered ships and submarines to date have relied on pressurised water reactor (PWR) technology and they have demonstrated an enviable record for reliability and safety when operated correctly.

However, other nuclear technologies soon may be available, including a range of high-temperature reactors, the pebble-bed concept, and designs developing on the original PWR concept.

Modern reactor technology has, since the early designs, progressively introduced enhanced safety and control features which make their use increasingly attractive and practical for merchant marine operations.

Nevertheless, the types of unmanned machinery spaces common in many modern ships are unlikely to be acceptable for nuclear-propelled vessels. Methods of crew-training also will need to undergo considerable modification.

In fact, a cultural shift will be essential in the marine engineering community if the lifecycle and environmental benefits of nuclear propulsion are to be realised, while managing the risks - both real and perceived.

Business models for ship purchases and operations also are likely to change significantly, since the majority of the costs are incurred earlier, during the build and commissioning stages.

In a nuclear-propelled ship, the fuel cost is included in the cost of the reactor. Ships that use conventionally enriched uranium then will be able to trade for up to five years before refuelling.

This refuelling period is not inconsistent with conventional survey periods, except the refuelling process would take about 30 days for a ship featuring a conventional PWR plant, under controlled conditions. The management of spent fuel, although established for the current industry in line with the conventional nuclear cycle, would also need to be thoroughly reviewed.

With conventional propulsion, the cost of the ship is broadly defined by its structure, outfitting and machinery; fuel costs are distributed throughout the lifecycle at frequent intervals.

The greenhouse gas challenge

Public concern for the environment in recent years has focussed on the way greenhouse gases are changing the world's climate. Although the marine industry contributes a relatively small proportion of those greenhouse gases in relation to the amount of goods and raw materials it transports, shipping's CO2 contribution from exhaust emissions is of growing concern.

A number of research initiatives have been introduced to mitigate this component of emissions from slow- and medium-speed diesel engines.

Lloyd's Register has been actively looking for the technological solutions to the challenges arising from ship propulsion to help the marine industry reduce its carbon footprint. Nuclear propulsion is one such technology, one that nullifies the industry's CO2 contribution.