Underground nuclear explosions detection methods
Developing and perfecting methods to detect venues of underground nuclear explosions the case of STS
Tech Area / Field
- OBS-GEO/Geology/Other Basic Sciences
- PHY-ANU/Atomic and Nuclear Physics/Physics
3 Approved without Funding
National Nuclear Center of the Republic of Kazakstan / Institute of Radiation Safety and Ecology, Kazakstan, Kurchatov
- University of California / Lawrence Berkeley Laboratory, USA, CA, Berkeley
Project summaryOn March 5, 1970, a Treaty on the Non-proliferation of Nuclear Weapons came into force. Control system of compliance with the Treaty consists in worldwide monitoring for the purpose of determining signs of a nuclear explosion. To achieve this goal there is a network of international monitoring stations - seismic, hydroacoustic, ultrasonic and radionuclide. States who signed the Treaty may require on-site inspection (LI) which aims at revealing whether a nuclear explosion was actually performed in violation of the Treaty.
On-site inspection is one of the 3 most important components in the surveillance mode of Comprehensive Test Ban Treaty (CTBT) alongside with the International Monitoring System of 337 stations and the International Data Center in Vienna. According to clause D.35 of CTBT, «…the only on-site inspection purpose consists in clarifying whether a test explosion was really performed in infringement of clause I and, as far is possible, in gathering any facts which could help identify any possible violator…». Kazakhstan like other member-states is obliged to cooperate with the CTBT organization in developing technologies and techniques to solve a challenge of revealing a secretly performed nuclear explosion. Research of this tendency in Kazakhstan within the framework of a specific subject started in 2004 and was carried out for the first time. Before those activities on CNTBTO projects started, two international on-site inspection field experiments were conducted at the Semipalatinsk test site (1999 and 2002), and in the course of works on the subject - two more field exercises (2005, 2008) which stimulated the research on this subject. In support of CNTBT, capabilities of both basic and (clause 69 of CNTBT Protocol) extra geophysical and geochemical methods were studied in terms of their information value with respect to the Semipalatinsk test site conditions and with the emphasis on such LI requirements as maximum reduction of terms to obtain actual data.
When assessing efficiency of these methods it is helpful to remind that at «Balapan» ground UNE were performed in vertical holes with a yield of up to 150 kt 400 to 800 m deep. In this case geologic-geophysical technologies arouse no doubt with comparatively simple and small observation systems: passive seismic earthquake converted-wave methods, resonant seismometry, active seismic method of diffracted scattered waves, magnetic field mapping, electric logging in the modification of field formation in the close-in zone. Using the active seismic method of ping waves despite its reliability in detecting zones of post explosive rock decompaction is complicated if the UNE depth is deep (dimensions for hardware arrangement and a source intensity increase and others.). At «Degelen» ground where UNEs were performed in tunnels at a depth of down to 200 m, inspection technologies are hard to apply due to mountainous terrain conditions. Some seismic technologies are inapplicable at all at a shallow UNE depth due to a complicated way to pick out wave phases or low resolution.
Account must be also taken of the experience in radioecological investigations at the STS, which showed that at «Balapan» ground approximately in 80% cases radioactive contamination of the daylight surface in UNE epicentral zones is insignificant (at the global fallout level). At that relief deformation on the daylight surface is poor or none at all. For which reason in the realistic environment the claimed LI methods efficiency will be poor when inspecting the UNE area in boreholes deeper than 500 m. A tritium method can significantly increase the LI efficiency. Field study findings and estimated data showed that a large amount of tritium is produced by neutron activation at the moment of a UNE was performed. Accumulated tritium in destruction zones of rock enters the daylight surface along with other gases. For which reason it can be indicative of UNE as the main evidence.
A variety of geological conditions in venues of nuclear explosions defines a different efficiency of regulated technologies and the necessity to improve them and to study capabilities of additional methods. The research experience gained in IRSE NNC RK in radiological investigations carried out in venues of underground nuclear explosions (UNE) at the STS territory can promote more successful and accelerated development of the On-site Inspection technologies. The new suggested methods of LI are widely used and constantly improved by IRSE NNC RK when carrying out a phenomenon research of disastrous nature which are related to underground gasification processes of rock at the STS territory. Tasks to create new techniques for finding out UNE venues have not been set so far. Along with that, such techniques can be successfully used in LI both inpidually and in combination with others. Portable equipment is used for this purpose . For which reason they require no heavy costs. And above all, for them to be developed in detail and improved there are real world areas UNE were conducted under various geological conditions.
The main objective of the Project is «Efficiency assessment of new suggested on-site inspection methods to reveal UNE venues via the example of STS objects». To correctly pursue the intended aim the following tasks are assumed to be set:
1. Systemizing and generalizing data on post explosion process behavior in UNE venues at «Balapan» and «Degelen» grounds.
2. Developing new LI methods on revealing and locating epicentral UNE zones at «Balapan» and «Degelen» testing grounds of the former STS.
3. Developing new LI methods on assessing the degree of rock deformation in epicentral UNE zones.
4. Checkup monitoring of identified UNE areas at «Balapan» and «Degelen» grounds.
5. Working out recommendations on using new LI methods.
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