Statement by the United States Representative (Martin) to the Conference of the Committee on Disarmament: Treaty on Underground Nuclear Explosions for Peaceful Purposes, August 10, 19761

At the end of our spring session, I announced to the Committee that the United States and Soviet delegations had concluded their negotiations on the agreement governing underground nuclear explosions for peaceful purposes pursuant to article III of the Treaty on the Limitation of Underground Nuclear Weapon Tests (the TTBT). I added that I expected to be able to report fully on this agreement during the summer session. On 28 May, after a review by both Governments of the ad referendum agreement, President Ford and General Secretary Brezhnev signed the Treaty on Underground Nuclear Explosions for Peaceful Purposes, the text of which was circulated to the CCD on 23 June. I am pleased that I can now report to the Committee on that agreement.

In the view of my Government, the Treaty on Underground Nuclear Explosions for Peaceful Purposes or PNE Treaty-represents a major contribution to the continuing effort to establish effective limitations on nuclear explosives development and to restrain further competition in nuclear armaments. The provisions of the PNE Treaty, together with those of the TTBT, which I described in my statement of 16 July 1974 establish a comprehensive system of regulations which will govern all underground nuclear explosions of the United States and of the Soviet Union.5

The agreement was reached by the two Governments after six rounds of negotiations over an 18-month period. It consists of a Treaty, a detailed Protocol to the Treaty, and an Agreed Statement delineating certain important activities which do not constitute a "peaceful

application," as that term is used in the Treaty. These documents, collectively, will govern all nuclear explosions conducted by either party at any location outside the nuclear weapon test sites specified by the terms of the TTBT, which explosions will be permitted only for peaceful purposes. Thus, the PNE Treaty will also govern all underground nuclear explosions for peaceful purposes that might be carried out by either the United States or the USSR in the territory of a third State. In such a case, these explosions would be subject to the implementation in the territory of that State, of the international observation and procedures contemplated by article V of the NPT and of the verification provisions of the PNE Treaty and its Protocol, including those regarding the necessary assistance, privileges, and immunities.

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An agreed and important goal of the negotiations was to ensure that no underground nuclear explosion carried out for peaceful purposes would provide weapon-related benefits otherwise precluded by the terms of the TTBT. If this goal had not been achieved, the limitations of the TTBT would not be meaningful. Of critical importance in this regard is the yield limit of 150 kilotons that the PNE Treaty places on individual explosions. As members of the Committee are aware, this yield limit is identical to the limit placed by the TTBT on nuclear explosions carried out at weapon test sites. It reflects the fact that a basis was not developed for accommodating individual peaceful explosions above the TTBT threshold without their providing weapon-related benefits otherwise precluded by the TTBT. This is largely because it has not been possible to distinguish between nuclear explosive technology as applied for weapon-related purposes and as applied for peaceful purposes.

Consideration of the question of carrying out individual peaceful nuclear explosions with yields greater than 150 kilotons is provided for at an unspecified future time. It should be emphasized, however, that the PNE Treaty prohibits such explosions, and amendment of the Treaty would be required to provide for them.

The Treaty also defines a category of explosions called "group" explosions: a group consists of several individual explosions in sufficiently close proximity in distance and time that teleseismic means cannot reliably distinguish between, and measure the yields of, the individual explosions in the group. The Treaty provides that the aggregate yield of a group shall not exceed 1,500 kilotons.

For any group explosion with a planned aggregate yield above 150 kilotons, the primary aim of the Treaty's verification measures is to ensure that no individual explosion in that group has a yield above 150 kilotons. In the case of such group explosions, the Treaty provides that observers from the verifving side will have the right to be present on-site before, during and after the explosions. At the explosion site they will be permitted to identify each individual component explosion and to measure its yield by means of instrumentation that meas

"Ibid., 1968, pp. 461-465.

ures the velocity of the shock wave in the close vicinity of the explosion. The observers will also verify that the circumstances of the explosion are consistent with the stated peaceful purposes.

Thus, the PNE Treaty constitutes an important milestone: for the first time nuclear weapon States have agreed to permit the presence of foreign personnel on their own territories for the implementation of an arms control agreement.

In order to measure the yield, the personnel of the verifying side can choose to bring to the site of the explosion their own equipment, the sensing elements of which would be placed close to the explosion. in accordance with the provisions of the Protocol to the PNE Treaty. Alternatively, observers can choose to use equipment provided by the party carrying out the explosion. In the event that the verifying side elects to use its own equipment, there is a procedure for shipment of two identical sets of equipment to a port of entry of the other party, which would then choose the set to be used in the verification process. Each of these sets would, in turn, contain duplicate components to be used for recording data and associated calibration equipment. After the explosion another selection procedure, this one by an agreed process of change, will allow the verifying side to retain in its sole possession one of the two identical sets of data-recording components and associated calibration equipment, while the other party may retain the remaining set for a specified time. In this fashion, the rights of both sides are equitably preserved-the right of the verifying side to a valid set of measurements, and the right of the other side to assurance that the equipment is not being misused to acquire unwarranted information.

When the planned yield of a group explosion is between 500 and 1,500 kilotons, the observers will, in addition, have the right to deploy a network of seismometers in the vicinity of the emplacement points of the explosives, to assist in verifying that no undeclared explosions are detonated along with the announced group explosion. The procedures described a moment ago for selecting and using yield verification equipment also apply to the equipment used for a local seismic network.

For explosions having yields between 100 and 150 kilotons, observers will be present if the need for their presence is mutually agreed to between the parties on the basis of information made available by the party carrying out the explosion or by the verifying side. Under these circumstances, the principal functions of the observers will be to confirm geological and other information in order to assist in the teleseismic determination of the yield of the explosion.

Observers will also confirm the geological and other information provided by the party carrying out the explosion at aggregate yields above 150 kilotons.

From this brief description of observers' rights it can be seen that the scope of observer functions increases with the aggregate yield

of an explosion. This is because at higher yields there would be greater opportunity for evading detection of a violation of the 150-kiloton limit on the yield of individual explosions. For example, the possibility of detonating an unannounced explosion of a yield above 150 kilotons under the cover of a group explosion with an aggregate yield in the range of 500 to 1,500 kilotons is greater than if the group ex-· plosion had a lower aggregate yield. Therefore, as I have noted, provision is made for a local network of seismometers in the higher yield range to provide additional assurance of compliance in such cases. Below 150 kilotons (unless the presence of observers is permitted as described above), the PNE Treaty provides for verification on the basis of national technical means alone, supplemented by detailed information supplied to the verifying side by the party carrying out the explosion. National technical means, assisted by such data, will provide adequate assurance that individual explosions having yields greater than 150 kilotons are not being conducted. Again, there is a scaling of yields and verification measures, this time with respect to the amount of information provided. For example, for each explosion with a planned aggregate yield greater than 50 kilotons, information would be provided about the purpose, location, date, planned yield. depth of burial, geology, number of explosives and their relative locations, the specific geological features of the project which could influence the determination of the yield, and the specific technological features which could influence the determination of yield and confirmation of purpose. This information would be provided at least 30 days in advance of the beginning of emplacement of the explosives. For explosions at lower yields, and for explosions at yields greater than 75 kilotons, respectively less or more extensive information provisions are established. For explosions with planned aggregate yields exceeding 100 kilotons, the information must be provided no later than 180 days in advance of the beginning of emplacement of the explosives. For all explosions, additional information, including the actual time and aggregate yield, must be provided to the verifying side not later than 90 days after the explosion.

The PNE Treaty also provides that any underground nuclear explosion for peaceful purposes must be carried out in compliance with other international agreements to which either or both sides are party. In particular, the Treaty reaffirms, in an operative article, the obligation of the parties to comply with the provisions of the Limited Test Ban Treaty of 1963, which prohibit any underground nuclear explosion that causes radioactive debris to be present outside the boundaries of the State in which the explosion was conducted."

In addition to the provisions for supplying information, the PNE Treaty provides for the establishment of a Joint Consultative Commission to facilitate additional exchanges of information, the establishment of procedures for the efficient implementation of the 7 Ibid., 1963, pp. 291–293.

verification procedures, and consultations regarding any questions of compliance which might arise.

The interrelationship of the TTBT and the PNE Treaty is further recognized by their identical 5-year durations, and by the provision that neither party may withdraw from the PNE Treaty while the TTBT remains in force. Conversely, either party may withdraw from the PNE Treaty upon termination of the TTBT.

By the terms of the Treaty, both parties also pledge to continue to fulfil their obligations under article V of the NPT, and 'to assist the International Atomic Energy Agency with regard to the international agreements and procedures referred to in article V.

The PNE Treaty also provides for the development of mutually beneficial co-operation in various areas related to PNEs. The sides will keep IAEA appropriately informed of the results of such cooperative efforts.

The Protocol to the Treaty spells out the procedures to be followed during the observation process, including such specifics as the number of observers, the geographical extent of their access, the provision of certain information, such as maps of the area of the explosion to assist in the planning of their activities, and essential matters of a legal nature that mainly provide for immunities for the observers, their quarters, equipment and records.

The Protocol also provides for certain additional constraints in order to assure proper functioning of verification procedures and to limit the opportunity for gaining weapon-related information. An example of the former is the set of formulas on allowed maximum and minimum distances between individual explosions constituting a group explosion. An example of the latter is the minimum depth requirement on any explosive emplacement point. Explosives buried at a lesser depth could provide militarily significant information, such as blast and electromagnetic effects produced by the explosion.

The Agreed Statement that accompanies the Treaty specifies that a "peaceful application" of an underground nuclear explosion would not include the development testing of any nuclear explosive. Such testing must be carried out at the nuclear weapon test sites specified by the terms of the TTBT, and, therefore, is treated as the testing of a nuclear weapon. Furthermore, it would not constitute a "peaceful application" if test facilities, instrumentation or procedures related only to testing nuclear weapons or their effects were associated with any explosion carried out under the terms of the PNE Treaty. Mr. Chairman, I realize this presentation has been somewhat lengthy and complicated. Nevertheless, it seems consistent with the length and complexity of the PNE agreement, which in turn reflects the difficulties, now successfully overcome, faced by the American and Soviet negotiators in developing an agreement that effectively complements the TTBT. The agreement demonstrates the ability to resolve