GB2129190A - Controlled maritime storage of noxious material - Google Patents

Abstract

The invention concerns the controlled maritime storage of radioactive waste material packaged e.g. in containers in a floatable and submersible storage space (1) divided into a plurality of sealable compartments (2), each adapted to be cooled with a closed cooling system (9). The arrangement permits the storage of radioactive material into, or the removal of material from, the sunk storage space (1) without the latter being dispaced. Apparatus is provided that is responsive to the condition of the stored material, and the information obtained thereby can be recorded in a remote recording station via a tower (13) mountable on the storage space (1). <IMAGE>

Description

SPECIFICATION Controlled maritime storage of noxious material The invention concerns a storage space for controlled storage of noxious material, and in particular of radioactive waste material packaged in containers or the like.

Various possibilities exist for the storage of this material.

One possibility is that the radioactive material is deposited in sea trenches far away from the inhabited world. Although such a storage is safe in itself over a prolonged period, there is no longer any control of the material once dumped.

It is indeed quite conceivable that possibilities are created in the future which ensure a definitive solution and which are entirely acceptable from an environmental viewpoint.

It would therefore be highly desirable to have a possibility to retrieve the radioactive material from the seabed in order to store it according to the improved technique. The retrieval of this waste material from the seabed, apart from the enormous cost, is extremely complicated, if not impossible for the time being.

Besides the dumping of radioactive material in the sea, it is also possible to store the radioactive waste material, packaged in containers or the like, in so-called salt domes, which are located at a rather large depth underground. Although this has the advantage that the radioactive material can be retrieved in a relatively simple manner and at reasonable cost, and moreover, intermediate corrections in the storage can be made against any undesirable developments, it is generally felt inconvenient that the salt domes are located too close to the inhabited world and that the waste material stored therein might come into contact with ground water destined for consumption, due to a possible movement of the ground layers wherein the salt domes are situated.

It is an object of the invention to provide a storage space wherein the radioactive waste material, stored in containers or the like, can be stored safely and controllably over a prolonged period, and can be retrieved therefrom later on in a simple and inexpensive manner, while moreover the storage space is located far enough from the inhabited world and hence does not constitute a risk for society and the ecosystem wherein the society functions.

The object is achieved in that according to the invention the storage space is a floatable and submersible construction which can be sunk at least partly into the seabed and which comprises a sealable access for the storage of the contaminant waste material in the construction.

Preferably, the storage space is divided into a number of separate compartments, each being sealable with an access hatch. The condition of the material stored in the compartment can be measured, recorded and controlled, e.g. by means of measuring and regulating apparatus. In case of undesirable developments, it is then possible to intervene, e.g. in the form of a forced cooling of the seawater or fresh water present in the compartments, if the temperature of the containers with the radioactive material stored therein threatens to become critical, or e.g. by lifting the storage space from the seabed and transporting the same to a different, better location.

A specific advantage of the above described storage space is that prior to being sunk, it is first entirely or partly loaded on the quay, or if poesible, at the location where the radioactive waste is produced, in order to be subsequently towed to the desired site and sunk at that location.

A great degree of flexibility in handling is obtained due to the possibilities of both a complete or partial loading of the storage space on the quay and in its submerged condition.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal section of a compartmented storage space on the lines I-I of Fig. 2, partly sunk into the seabed, said compartments being filled under water with the waste material e.g. by means of floating shears: Fig. 2 is a top view of the storage space of Fig.

1; Fig. 3 is a side view of the storage space.

The drawings show an elongate storage space 1 divided into a plurality of separated compartments 2, each being sealable with an access hatch 3. The storage space is preferably made of reinforced concrete to make for a long life, and is designed in such a manner that it is floatable and at the same time a submersible construction having sufficient stability and being adapted to be restored to its floating position from its sunk position. Instead of reinforced concrete, a different material or material combination with a long life can be chosen and possibly with a sufficient shielding factor for radioactive radiation.

The construction should be provided with a seal for preventing osmosis.

It is clear that besides an elongate construction, other forms are possible. With a view to a floating displacement over the sea 4, an elongate form is clearly preferred.

In general, the storage space 1 will be constructed in a dry dock and be towed therefrom to a desired location for being sunk and placed partly into the seabed 5 by means of e.g. suction dredgers, not shown, thereby fixing its location.

The installation of the storage space in the seabed should be such that at least the access hatches 3 project above the seabed.

By means of floating shears the radioactive material supplied by a vessel 7 and packaged in containers 8 or the like, can be placed in the respective compartments via the opened access hatches 3.

Due to the application of separate compartments, different types of radioactive waste can be stored separately, with the additional advantage that the storage space can be filled in stages.

Besides the sealing the with the access hatches 3, additional sealing may be provided by applying submarine asphalt over the access hatches or pouring concrete thereon. Such a sealing ensures substantially that the sea water or fresh water present in the compartments and possibly "contaminated" via the containers, due to the under-water loading, cannot come into contact with the sea water outside the storage space. The packing of the waste material may be provided, if necessary, with cathodic protection.

If desired, each compartment can be separately forcibly cooled, by means of a closed cooling water circulation system 9, by the - insulated - sea water or fresh water present in the compartments. Said cooling water circulation system can serve as an additional safety in case in a given compartment, the temperature of a container present therein threatens to become critical due to heat generation by the radioactive waste material. Here too, the advantage of the separate compartments is obvious, since undesirable effects, if any, remain restricted per compartment.

When the storage space is provided with a closed cooling water system, this can be accommodated in a suitable separate compartment; 10 within the storage space 1. The driving portion of the cooling water circulation system can be forcibly cooled with the outside water, via a socalled interstage cooling 11. Such a compartment may also accommodate measuring and regulating apparatus for measuring, recording and controlling the conditions in each of the compartments 2, the measuring results being transmitted via a transmitter to a central recording station ashore.

There may also be provided an under-water lock for under-water access to the compartment 10.

Underneath the compartment 10, there may be provided a compartment 12 containing a power source for the cooling water circulation system and the measuring and regulating apparatus.

If desired, the measuring and regulating apparatus can be accommodated on a tower 13 constructed on the storage space 1, said tower projecting above the water surface 4, and also accommodating the transmitter. Said tower may have such a construction that access is obtained to the compartments 10 and 12 via the interior of the tower. The tower is an important stabilizing factor during the sinking phase of the storage space, said tower being removably coupled to the storage space in order that the apparatus housed in the tower may be repaired or replaced elsewhere.

The cooling water circulation system 9, at least its driving portion, and the power source may also be accommodated in the tower.

The presence of apparatus compartments 10 and 12 and/or tower 13 may for instance depend on the depth of the seabed wherein the storage space rests. It is clear that even without these elements a highly controlled storage is obtained.

The sinking may be effected by pumping sea water into the compartments of the storage space.

After the application of the access hatches the sea water in the compartments may be replaced by pumping fresh water into the compartments so as to create a less corrosive environment for the containers stored.

Claims (5)

1. A storage space for the controlled storage of noxious material packaged in containers or the like, characterized in that the storage space is a floatable and submersible construction adapted to be sunk at least partly into the seabed.

2. A storage space according to claim 1, characterized in that the storage space is divided into a plurality of separate compartments, each being sealable with an access hatch.

3. A storage space according to claim 1 or 2, characterized in that the storage space contains apparatus responsive to the condition of the noxious material stored in each compartment, while.the information obtained can be recorded in a central recording station.

4. A storage space according to claim 3, characterized in that the apparatus comprises a closed cooling water circulation system for separately cooling each compartment when the noxious material threatens to obtain an undesirably high temperature.

5. A storage space for the controlled storage of noxious material, substantially as herein described with reference to the accompanying drawings.