How does site investigation expertise support the nuclear test ban treaty?


Whilst on-site inspections are unique, it is RSK’s expertise in geotechnical, geoenvironmental and geophysical investigation that helps solve the challenges faced by the UN. These are to:

  • work efficiently
  • have tasks with clear objectives
  • communicate results clearly and concisely
  • use the correct ground investigation techniques in the right places understanding the value and limitations of the information they return

RSK’s ground investigation experts helped write the United Nations procedures for on-site-inspections; a pillar of the Comprehensive Nuclear Test Ban Treaty verification regime. These may be the most high profile and difficult site investigations ever undertaken. An on-site inspection seeks to establish whether or not a nuclear explosion has been carried out. It will be launched at very short notice, and could be in any location in the world.

The inspection identifies locations to collect samples which will be analysed for isotopes diagnostic of an underground nuclear explosion. If the explosion has been contained, the investigation should locate ground zero and request permission to drill. The inspected State Party has the right to see all evidence collected, obtain copies of data, and retain portions of collected samples.

There is a very narrow time window to collect some of the evidence. Seismic aftershocks only occur for a short time after an event, and some radionuclides have short half-lives. The inspection team should be on site six days after the request for the inspection is lodged, and has to submit a first progress report detailing technical findings and recommendations within 25 days. The inspection can take a maximum of 130 days.

Putting in place a legally binding ban on nuclear test explosions is one of the UK government’s key disarmament and non-proliferation priorities. “We contribute world-leading expertise to help build up the treaty’s verification regime. The treaty’s entry into force will strengthen our own national security and will strengthen global security. We will all be safer with this treaty than without it,” William Hague, UK Foreign Secretary, 2011.

RSK helped to develop the concept of operations for on-site-inspections which brings together the requirements of the treaty, the objectives of site inspection, and the deployment procedures for each ground investigation technology into a coherent working system. It defines how the inspection team manages its activities, its internal communication and reporting, its decision making procedures and the search logic. That concept is documented as “Inspection Team Functionality”, commonly referred to now as “The ITF”.

The challenge was to create a method of working that delivers a very technical ground investigation in the time scale of the treaty. The team of just 40 inspectors must include all the technical expertise, logistical and medical support required to operate as a self sufficient unit anywhere in the world. They must search the 50km2 inspection area for signatures of an underground explosion, including geomorphological anomalies, anthropogenic signatures, disruption to geology and hydrology, and radiological contamination. The Treaty prescribes the techniques that can be applied. These include: overflights, visual observation, video and still photography, multi-spectral imaging, radiation monitoring, environmental sampling, seismic monitoring, airborne and ground geophysics, and drilling.

Inspection Team Functionality

The ITF uses discrete field missions as the building blocks of an inspection’s technical activity. The decision process is driven by developing and prioritising missions, which in turn drives the requirements for internal communication and reporting. However, an efficient team does not in itself guarantee the technical aims of an OSI will be achieved. This requires a robust search logic.

The linked concepts provide an excellent approach to the design and execution of all site investigations

It prescribes an efficient, objective, defensible working method. Central to this is asking the right questions to get the right answers, and ensuring that heuristic bias, which is inherent in all decisions based on expert opinion, is recognised and controlled. To take an exaggerated example, an inspector who’s day job is the analysis of soil samples for radionuclides will tend to frame questions in terms of the possible presence of radionuclides in the soil, will design missions based around soil sampling, and will not contribute to the wider aims of the inspection. Inspectors must be trained to recognise this tendency for bias and consciously avoid it.

The concept, co-developed by RSK, seeks to remove all heuristic bias from the questions by making them independent of the methods or technologies that might be used to investigate the site. Other bias that might influence the investigations, including equipment and software limitations, the interpretative experience of expert inspectors, and the pressures and politics of the treaty, should also be recognised, and addressed directly during training.

The linked concepts, and the separation of questions, answers, and ground investigation methods are captured in the graphic below. It is striking how changing “OSI mission” to “ground investigation” provides an excellent approach to the design and execution of all site investigations.

OSI linked concepts, illustrating the separation of bias, which are equally applicable to all site investigations

OSI linked concepts, illustrating the separation of bias, which are equally applicable to all site investigations

Search Logic

An OSI is unique in its requirements for a search logic not only in the complexity of the observables being sought, but because the object of the search would be concealed or may not exist. RSK led the development of a new search logic which takes all available information and provides a rationale for assigning priorities to each activity. It is designed to allow the inspection to progress efficiently, with clarity of purpose, and with the bias of human decisions minimised.

The inspection team must think imaginatively about the information that is available, and consider what it means in terms of the purpose of the inspection. The process relies on the expertise and intelligence of the full inspection team focussed through clear hierarchical communication channels, and the output is a finite number of location specific unanswered questions, which in turn defines the missions.

It is also vital to know the capability of each GI technology to detect the relevant observables. The team must understand the likelihood that a particular technique will return the information required, and must avoid committing resources to missions with little or zero likelihood of success.


The Big Test

IFE14 is the biggest test yet of the ITF concepts, as well as the logistical and technical capabilities of the people in the inspection team. The results of many years of training and development since the last big field exercise in 2008 are on show for the world to see.




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“…it is time for the testing of nuclear weapons to finally be banned.” President Obama, Prague, 2009.