the containment shell ventilation unit and the fresh-air supply to all the compartments in the reactor zone. These last-named are kept at under-pressure in relation to the adjacent ship's compartments and to the atmosphere, so that uncontrolled air movements can occur only from outside to inside. The radioactivity in the air passed out of the reactor zone is to be monitored constantly. Numerous tests are planned in an attempt to cut down the cost, weight and size of these installations.

6. The entire ship is monitored by radiation counters, not only on safety grounds but also in order to improve radiation shielding devices. In this connection mention should be made of the fact that the primary unit shielding is so effective that the inside of the containment shell can be entered for brief periods via a spherical lock during operation. This was done to facilitate research work, despite the resultant increase in weight and space.

7. Other equipment is to be used for research in ship-building and operating. For example, detailed investigations are to be carried out on the strength of the ship and also on her propulsion characteristics.

In conclusion, the Otto Hahn can be described as a floating laboratory and no expense has been spared to enable new information to be acquired.

CONSTRUCTION PLANS FOR ECONOMIC NUCLEAR MERCHANT SHIPS

Since 1961 Euratom has been participating under contracts of association in development projects which are being carried out on the one hand by the Reactor Centrum Nederland (RON) and on the other, with the support of the Italian Atomic Energy Commission (CNEN), by Fiat, acting as the reactor construction firm, and Ansaldo, acting as the shipbuilder. Although the programmes of both these contracts have the same aim at present, i.e. the drawing up of construction plans for economic marine-type pressurised-water reactors, the individual technical designs involved are all so different that the current experimental and theoretical studies do not overlap. The draft designs elaborated under each programme are constantly being improved in line with the latest research results.

This work will probably not be completed, and the final construction plans drawn up, until at least some of the results of major experiments carried out with the Otto Hahn are available and can be taken into account.

EXTENDING THE LIFE OF A REACTOR CORE CHARGE

An example of different technical designs fulfilling the same purpose is provided by methods for prolonging the life of a reactor core charge. These involve the insertion into the core, in addition to the control rods, of neutron-absorbers, by means of which it is possible to offset a very high excess reactivity in a new core. This compensating effect must decrease during operation in proportion to the core reactivity drop brought about by the formation of fission products. In the Otto Hahn reactor some fuel rods are replaced by rods filled with boroncontaining material, the neutron-absorbent properties of which decline during operation, and which is thus called "burnable neutron poison". Improved techniques for achieving a more uniform neutron-flux distribution are now being developed. Fiat is conducting investigations to determine whether liquid neutron poison dissolved in the primary water can be used in a marine reactor. The RCN is attempting to mix poison with the uranium dioxide fuel in the form of solid particles.

SAVING WEIGHT AND SPACE

The desire to save weight and space on the one hand and on the other to make for easy maintenance and repairs has likewise resulted in the examination of a variety of solutions, the choice of which will also be influenced by the construction cost factor. Under the RCN project there are two steam-generators which are not, as in the Otto Hahn reactor, to be "integrated" in the pressure vessel but installed alongside the pressure vessel, each forming one single unit with a primary pump, for reasons of accessibility. Fiat and Ansaldo have, however, devoted particular attention to a so-called "compact" design, in which the steam-generators are mounted right next to the pressure vessel, and are examining the advantages of this type of construction in comparison with the fully integrated design. Interest is also being shown in different primary circuit designs, the main purpose of which is to achieve a high power density in the

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core. Dual flow in the core is envisaged under the Italian project. The primary water flows under the pressure generated by pumps from top to bottom in the outer core zone and from bottom to top in the inner zone. The fuel in both zones is enriched to varying degrees with fissile uranium-235:

Under the Dutch project, which also has a two-zone core, the water flows through the core in only one direction, but only some of the heated primary water is passed to the steam-generator, the remainder being recycled to the

core:

As can be seen from the remarks below, the two programmes are also complementary in the sense that various fields are mainly studied in Italy and others in the Netherlands.

SPECIAL ASPECTS OF THE ITALIAN PROGRAMME

Before Euratom and its Italian partners agreed in May 1963 that a pressurized-water reactor fitted with primary water pumps ensuring forced circulation in the primary circuit should be taken as the basis for further development work, a comparative study was undertaken of pressurised- and boiling-water reactors with both forced and natural circulation. In addition, tests were conducted to determine the feasibility of a boiling-water reactor without steam generator, i.e. with a direct reactor-to-turbine cycle. This study provided an insight into the basic assets and drawbacks of the various types and revealed that the research and development work necessary to adapt the forced-circulation pressurised-water reactor for marine uses involves considerably lower costs than the other types of water reactors.

With the collaboration of the Ansaldo shipbuilding firm, particularly detailed studies are also being carried out under the Italian contract on naval constructional features aiming at the optimum operation of the nuclear propulsion unit. The dovetailing of shipbuilding and reactor technology results in the emergence of new perspectives which are of decisive importance to further developments. The shape of nuclear tankers, for instance, is to be designed in such a way that the ship can travel at the high speed corresponding to full reactor power when unladen, i.e. when she is high in the water, for a reduction in reactor power does not result in appreciable fuel savings, as in conventional ships.

SPECIAL ASPECTS OF THE NETHERLANDS PROGRAMME

The Dutch programme lays special stress on experimental tests yielding results which may lead to the improvement of existing computation processes and the development of new ones. With Euratom's support, two assemblies have been built at the Petten research centre, in which reactor cores can be simulated and physical measurements carried out, in particular, of the neutron flux distribution with various fuel element geometries and control rod and neutron poison arrangements. In the one assembly the nuclear fission processes are allowed to proceed until a chain reaction is maintained (critical experiment), while the other assembly operates in the sub-critical range.

At the Petten centre there has also been set up a loop for testing the corrosion resistance of reactor construction materials at a pressure of 140 kg/cm2 and a temperature of 300° C. together with an installation for examining complete fuel elements under irradiation at 325° C. and a pressure of 140 kg/cm2 in the Petten high-flux reactor. Furthermore, thermodynamic and hydrodynamic test installations have been installed in the laboratories of the Eindoven and Delft technical universities. An installation now under construction at Eindhoven is to be used for studying heat transfer from a primary to a secondary circuit. The model of a steam-generator with superheater to be employed for these experiments will have a heat transfer power of about 6 MW. On completion of the work for the Dutch marine reactor project, it will be possible to place the unit at the disposal of other interested parties in the Community.

DEVELOPMENT WORK OF GENERAL IMPORTANCE FOR NUCLEAR-POWERED
MERCHANT SHIPS

The Euratom programme would be incomplete if it were confined to participation in individual reactor projects. As was to be expected, Euratom's coordination work slashed costs particularly in those fields involving problems common to all marine reactors and which call for expensive testing and wideranging theoretical studies, especially since in the latter case account must be taken of the cost of computers. The contracts concluded between Euratom and the RCN and the Italian firms of Fiat and Ansaldo cover, besides the work

already mentioned, such fields as research into radiation shielding and model tests aimed at the development of protective structures against collision at sea. Furthermore, in addition to the contract providing for its participation in the Otto Hahn project, Euratom concluded an agreement with the Gesellschaft für Kernenergitverwertung in Schiffbau und Schiffahrt GmbH (GKSS) back in 1961, for a provisional period of five years, covering the optimisation of radiation shielding and tests on the mechanical strength of reactor components.

THE OPTIMISATION OF RADIATION SHIELDING

In marine reactors it is essential to avoid making the radiation shielding bigger than is absolutely required for safety. For this purpose it is indispensable to have precise data on the degree to which the reactor's radiation, consisting largely of neutrons and gamma-rays, is attenuated on passing through "opaque" materials. Since water, owing to its hydrogen content of low atomic weight, is particularly suitable as neutron shielding, while metals such as iron and lead, owing to their high atomic weight, absorb gamma-rays, radiation shields can be made of metal plates with layers of water between them.

The GKSS swimming-pool research reactor at Geesthacht near Hamburg, which with its two cores can produce a thermal power of 5 MW, is fitted with devices for the measuring of the radiation absorbed in small (60 x 60 cm) and large plates (2 x 2.5 m). Since the smaller plates, which are made of various materials and can be used in different thicknesses, are cheaper, they are suitable for preliminary tests in which particularly effective combinations of plates and water-filled spaces can be selected. In order to improve the measuring accuracy the reactor radiation is first converted into parallel beams (collimated) and directed through an opening at a test shield, the total thickness of which can amount to 60 cm: For thicker shields of up to 120 cm and to obtain accurate measurements (in which all the secondary radiations and phenomena stemming from the irradiated substances can be picked up), the larger plates are used. They are set up near the reactor core in a cradle which can be placed into one of the reactor's swimming-pools by a crane. In addition, the Geesthacht reactor is fitted with an aluminum-lined tunnel extending into another of the three swimming-pools. A trolley carrying shielding plates can be driven into the tunnel to the vicinity of the reactor core situated in the adjacent pool. The tunnel can be filled with either gas or any liquids required.

The measurements carried out with these units were supplemented by experiments with the swimming-pool research reactor owned by the Sorin company at Saluggia, near Turin, which is being used under the Fiat-Ansaldo contract. This work was found to be valuable, since a different type of radiation is available there. 1 x 1m3 plates are penetrated by radiation emitted from a uranium plate which is exposed to the reactor's radiation. By measurements carried out on similar plate geometries at Saluggia and Geesthacht with identical instruments, a better understanding can be gained of the nuclear processes involved. The results are used for checking and improving computing methods which, once their reliability has been experimentally proved, can serve to calculate shielding specifications accurately and at low cost. The RCN and Euratom's research centre at Ispra are participating in the theoretical work.

RCN experts are participating in the experiments which are being carried out at Geesthacht for the Dutch marine reactor project. While substantial progress has been achieved in the last few years, the studies devoted to possible ways of improving the measuring and calculation methods are still in full swing, so that the optimisation of radiation shielding cannot be regarded as completed yet.

OPTIMISATION OF COLLISION PROTECTION

Thanks to statistics on collisions which have actually occurred between conventional ships, which were of course not fitted with collision barriers, it proved possible to determine the amount of impact energy absorbed by different types of hull. Probability calculations based on these statistics showed that the anticollision structures designed and built hitherto afford a high degree of safety. The results of model tests are to be analysed in order to achieve even greater safety margins and to single out those types of structure which, while being more efficient, make possible lighter and cheaper collision barriers.

Four models of the bow section of the striking ship and four of the midships section of the struck vessel (scale 1:15) have so far been built and tested under the Fiat-Ansaldo contract.

A unit consisting essentially of a ramp for the bogie-mounted striking model, an attachment device for holding the struck model, and the measuring instrumentation, was made available by the University of Naples with CNEN backing. This rig differs from a GKSS-financed installation in Hamburg only in the method of fixing the struck model. At Euratom's suggestion, a collision will be produced on both test rigs between an identical pair of models, the struck model, as a conventional ship, having no collision barriers. By comparing each set of results both with one another and with those of an actual ship collision, their validity can be assessed.

The tests already carried out in Naples have shown that the degree of concurrence with actual conditions is adequate for comparison of the effectiveness of various anti-collision structures. The test programmes under way in Naples and Hamburg were drawn up jointly, and the results obtained are exchanged. Professor Spinelli, who is using the above-mentioned installation at the University of Naples for more general research on behalf of the CNEN, is also taking part in this exchange of information.

INCREASING THE MECHANICAL STRENGTH OF REACTOR PARTS

The risk that nuclear plant components, such as fuel elements, control rod drives, electronic control equipment, etc., might fail on board owing to inadequate mechanical strength can be largely discounted thanks to the test-rig set up at Geesthacht with Euratom's participation. On this installation, which is electrically-operated and is of unique design, test samples weighing up to 2.2 tonnes can be simultaneously moved with a vertical 3 m travel and oscillated with a maximum amplitude of ±45° for unlimited periods. In this way it is possible to simulate a ship's movements in a rough sea. The test samples can be subjected to accelerations up to a maximum of three times the acceleration due to gravity.

This "rolling-rig", which has been in constant use since its completion in 1962, has proved highly successful. In several cases unexpected mechanical flaws were detected in the test samples, leading to improvements in the design.

Eurotom and the GKSS, which consult annually to decide on requests from interested parties who would like to use the rolling-rig, bear the cost of staffing and operating the installation. The construction and mounting of the test samples, on the other hand, are financed by the client.

COLLABORATION IN THE EUROPEAN COMMUNITY

The above survey of the Euratom-backed programme for the development of nuclear-powered merchant ships clearly testifies to the value of collaboration between the parties concerned in the European Community. Further evidence of this are a number of sub-contracts, drawn up under the Euratom contracts already mentioned, with research institutes and firms throughout the Community. These include participation by the German Allgemeine Elektricitäts-Gesellschaft AG (AEG) in tests conducted by Fiat and Ansaldo in the field of boilingwater reactors, collaboration by the French firm of Indotom in the drawing up of construction plans for the Otto Hahn reactor, and the preparation of critical experiments to be carried out for the Italian project on the Dutch installation at Petten. Apart from certain individual areas of study, collaboration on fundamental matters is in the hands of a Community liaison committee, in which, in addition to Euratom and its contract partners, the governments of the Community countries and Euratom's Scientific and Technical Committee are represented. This committee regularly discusses and compares all the activities now in progress or projected in the Community in order to single out starting points for the orientation of further joint action.

In conclusion, it should be noted that while the development work on marine reactors now in progress in the Netherlands and Italy has not yet led to the adoption of a final design, those technical solutions which show promise are being followed up under the co-ordinated working programmes and there is good reason to expect that the nuclear merchant ships built in the Community after the Otto Hahn will at least reach the threshold of profitability.

The CHAIRMAN. Our next witness will be Mr. Herbert Hansen, vice president of the marine department of the Waterman Steamship Corp.

STATEMENT OF HERBERT HANSEN, VICE PRESIDENT, WATERMAN STEAMSHIP CORP.

Mr. HANSEN. Mr. Chairman and members of the committee, I am vice president of the Waterman Steamship Corp., in charge of the marine department, responsible for the operation, maintenance and repair of the vessels owned and operated by Waterman.

For the past 30 years, I have been directly involved with the operation of oceangoing vessels, having spent 10 years aboard ship in several capacities, including that of chief engineer. For 20 years I have served in various shoreside capacities in the industry. During the period 1958-63, I was project marine superintendent of the NS Savannah when the vessel was being operated by States Marine Lines, Inc. During 1963, 1964, and 1965, I served as consultant to the Maritime Administration on the Savannah before joining Waterman in mid-1965.

The management of Waterman Steamship Corp. has, for the past 2 years, been following the development of merchant marine applications of nuclear power and the performance of the Savannah with great interest. We are convinced that nuclear power is well suited for use in the large, fast merchant ships now being planned to serve the various trade routes in our foreign commerce where a large volume of high revenue cargoes is involved. It is our belief that nuclear power will develop its full potential in vessels of this type operating on the long trade routes and will, when fully developed, place us in a good position to produce a fleet of highly productive vessels which will, in turn, permit us to compete with foreign vessels on a favorable basis.

The day of very large, specialized, high-speed merchant ships is here and it does not appear practical to use conventional powerplants in these vessels due to the large quantities of fuel such ships must carry and consume, particularly in the long trade routes. Nuclear power appears to be the most promising source of power for ships of this type.

Approximately 1 year ago our company replied to a questionnaire prepared by the Maritime Administration to the effect that we would be interested in building and operating a fleet of 12 nuclear ships to be used on the various trade routes we serve. At the time we prepared our reply to the MARAD questionnaire, we were of the opinion the Savannah would be operated for the next few years and were quite surprised to learn a few months ago that the early layup of this vessel is contemplated.

It is our opinion that the Savannah should be kept in operation, for many reasons, if we are seriously interested in revitalizing the U.S. merchant marine and in building a new generation of nuclearpowered merchant ships. Other companies apparently feel as we do— generally sharing our views.

The Savannah is, in addition to being a proud symbol of the American merchant marine, a valuable training and development facility. In spite of the problems she has encountered during her rather short life, she has added immeasurably to our knowledge of nuclear vessel operations, opened the ports of the world to nuclear merchant vessels and, in the process, the program has produced a significant number of trained and knowledgeable seamen and staff members.