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Turning the Mirror on Ourselves


By Guillermo Arroyo, WANO Interface Officer, Nucleoeléctrica Argentina S.A.

Internal Technical Support Missions: A valuable tool for improving company expertise

With the Internal Technical Support Missions (called MISTI in Spanish abbreviation) Nucleoeléctrica Argentina S.A. (NA-SA) has resulted in more effective and efficient method for problem solving by the interchange of knowledge and experience, obtaining realistic and feasible solutions under a systematic approach by using best practices in the company and the industry.

A great differentiator in today's worldwide nuclear power business is the continuous effort to achieve levels of excellence in safety, quality, reliability and performance.  

WANO leads its members to the nuclear safety excellence, considering the experience exchange as a valuable tool towards the continuous performance improvement.

In this way, NA-SA recognised the importance of sharing personnel experience and it made this sharing part of the personnel daily work, within and outside of pertinent organisations.

With this aim, in 2011 NA-SA started the implementation of an internal review process in which a review team with experience in particular subjects assist to other organisation to identify problems to make suggestions for improvement. This process was named MISTI (Internal Technical Support Missions).

This process has been applied mainly between NA-SA plants, including support organisations allowing improvements according to the support experience and useful insights provided by the team of colleagues performing the mission. Since 2011, a number of 23 MISTI missions were performed as per Annual Programmes previously elaborated and approved.

For each mission, part time dedication work starts two months ahead of the mission planned date, by exchanging documents and by designating the Team Leader, the Expert Team and the Host Interface. The mission itself takes between three or four days full time, in which the Host and the Reviewers develop intensive and motivated efforts oriented to results.

The main idea behind the MISTI missions is the possibility to perform factual analysis of problems and issues. Such methodology, which is successfully used in the WANO Technical Support Missions, attempts to focus the Experts' attention to existing organisation concerns. 

The gap analysis between facts, standards and procedures according to each field experience allows detecting important findings during the first MISTI stage.

In the second stage, the findings are reviewed and grouped in key issues that require solutions. This allows also to identify areas of improvement.

Finally, the solutions to be implemented are defined, considering resources, time, priorities, and interfaces by the host organisation. 

The MISTI process achieved good results in many subjects, for instance: Housekeeping, Maintenance Human Performance, Operational Conduct in Control Room, Administration and Control of Dose Instruments, Monitoring of Corrective Actions, and other subjects contributing to safety and quality were also benefited.

In 2013, NA-SA asked to WANO a Technical Support Mission (TSM) to observe one MISTI mission in action with the objective to obtain opinion concerning the convenience of these internal missions and potential opportunities of improvement.

As a conclusion of this TSM, WANO stated that: "The WANO TSM highlights that the process established by NASA to conduct crossed support missions between their two sites based on the WANO TSM methodology is innovative and valuable for its potential use in other organisations with multiple sites".

After that, during the Embalse Peer Review in 2014, MISTI process was declared as strength for enhance exchange of experience among its plants and contribute to improvement of their performance.

Recently in 2016, WANO London Office has identified the MISTI process as a Good Practice and recognised the singularity, convenience, and added value of this methodology.

As the MISTI process was implemented within NA-SA, the different organisations and departments had the chance to focus and resolve problems more effectively and efficiently. The process led to feasible cost-effective solutions.

In this regard, the MISTI mission results have exceeded original expectations, consolidating in NASA a simple, effective, and profitable process towards continuous improvement, which is an extremely important and distinctive objective in the nuclear industry worldwide.


Guillermo H Arroyo is a graduate in Mechanical Engineering, having completed a post graduate degree in Operating and Running Nuclear Power Plants issued by the National Commission of Atomic Energy at Atucha Nuclear Power Plant in 1976.

During his 40 years of experience in the nuclear industry, he was involved in Embalse Nuclear Power Plant construction as a Supervisory Engineer and he was member of the Head Office Engineering Management. In Atucha I Station, he held the positions of: Quality Assurance Manager, Mechanical Maintenance Manager, Production Manager and Manager of the Management Technical Assistance Department. Currently he is Deputy Production General Management that represents the Operating Plants of Nucleoeléctrica Argentina S.A.

He has participated in several IAEA missions, WANO Peer Review and Follow-up Missions, and he was Host Interface Representative on several occasions.

In August 2010 he was appointed WANO Interface Officer.