N-bomb tests: it's easier to verify a total ban

The Reagan administration recently announced its intention to postpone talks on the Comprehensive Nuclear Test Ban Treaty (CTBT) until verification problems related to nuclear test limitation treaties can be resolved. The administration has failed to recognize, in public, that a complete test ban and test limitations are two different propositions. It is much easier to monitor compliance with a total test ban than with test limitations. Thus the argument that a test ban treaty must await solutions to the problems of verifying test limitations is spurious.

In truth, the administration's espoused concern about verification is a subterfuge, meant to deflect attention from the fact that nuclear testing is an integral component of the President's arms buildup.

Any arms control treaty or agreement involves the risk that signatories might choose to violate the treaty clandestinely, and succeed. In order to minimize another country's incentives and opportunities to violate an arms control agreement secretly, the United States employs a variety of means: satellite surveillance, radar, seismic sensors, electronic monitors, and human intelligence collection. These verification capabilities are designed to detect actual violations and, more important, deter potential violators by increasing the probability that noncompliance will be detected.

Each party to an arms control agreement must consider the trade-off between risks and benefits: Do the risks of undetected noncompliance outweigh the benefits of compliance? A recent Congressional Research Service report states ''. . .it is generally held that no. . .agreement is completely verifiable. The question becomes how much uncertainty can be accepted in exchange for an agreement, as opposed to demanding complete verifiability, which would preclude any agreement.''

When examined in terms of risks and benefits, the increase in our national security that the CTBT offers far outweighs the very limited risk of failing to detect non-compliance.

The risks associated with a test ban agreement are smaller than those associated with other types of proposed arms control treaties, i.e., START, chemical weapons, etc. There is general agreement that modern seismic verification capabilities permit the detection of even very low yield nuclear test explosions. The problem is to distinguish between seismic signals from smaller tests and those of natural seismic events, and thus to identify a particular seismic event as either man-made or natural. The CTBT would require the Soviets to explain all ambiguous seismic occurrences, thereby resolving the identification problem. As the size of a test exceeds five to ten kilotons, the probability of detecting and identifying nuclear explosions dramatically increases.

The most recent round of CTBT negotiations (completed in November 1980) made considerable progress on verification issues. Britain, the US, and the USSR agreed to place ten tamperproof seismic sensors on the territory of both the US and the Soviet Union. (The number to be located in the United Kingdom was not decided.) Data from these stations would be monitored by all parties to the treaty, and by an independent panel of international seismic experts.

The three countries also agreed on a framework for resolving disputed seismic and surveillance data, including on-site inspection in disputes which cannot be satisfactorily settled through additional data exchange and discussion.

What would be the consequences of Soviet testing if our verification measures failed? The yields of clandestine tests would have to be small, below approximately five kilotons, to avoid seismic detection. Five kilotons is one-thirtieth the size of the smallest Russian warhead currently deployed, and one-hundredth the size of the standard Soviet strategic warhead. Clearly, such tests would provide the Russians with little useful information about full-size weapons.

In addition, because significant military results are likely to be achieved only from a series of tests, rather than from a single test, multiple tests would substantially increase the likelihood of detection.

In sum, the chances of failing to detect Soviet violations of comprehensive test ban are very small.

The benefits of the CTBT are threefold.

First, the CTBT would severely inhibit the proliferation of nuclear weapons to the ''near nuclear'' countries (Argentina, Brazil, India, Israel, Pakistan, and South Africa). An agreement signed by the three nuclear superpowers would put heavy domestic and international pressure on these states to refrain from testing. Since all countries that have developed nuclear weapons have found it necessary to test prior to reaching full nuclear capability, the CTBT, by inhibiting testing, would curb the ''horizontal proliferation'' of nuclear weapons.

Second, concluding the CTBT would increase America's credibility in the world political community. In the Limited Test Ban Treaty of 1963, the US, USSR, and Great Britain pledged to ''achieve the discontinuance of all test explosions of nuclear weapons for all time'' and stated that the parties were ''determined to continue negotiations to this end.'' Therefore, a test ban treaty would redeem an American promise that has been outstanding for 19 years.

Third, the CTBT would halt the momentum of the arms race in both the US and Russia. A ban on all testing would prevent further improvements in warheads that might be used in future weapons systems. It would also establish a better climate for the current Strategic Arms Reduction Talks (START) and Intermediate Range Nuclear Forces (INF) negotiations.

By dropping the comprehensive test ban negotiations, the administration has discarded its most useful tool for checking nuclear proliferation. President Reagan would demonstrate true statesmanship by reversing his position and calling for an early resumption of them.