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Whiskers are electrically conductive, crystalline structures of one metal that sometimes grow from surfaces where this metal is used as a final finish. Whiskers have been observed to grow to lengths of several millimeters (mm) and in rare instances to lengths up to 10 mm. Whiskers are not a new phenomenon. Indeed, the first reports of zinc, cadmium and tin whiskers date back to the 1940s.
A single accepted explanation of the whisker growth mechanisms has not been established.
But according to the literature and many recent observations, whisker growth might be driven by two key factors: Formation of intermetallic compounds, which is accompanied by a build-up of bi-axial microstress in the metal layer, and the ability of such metal layers to release this stress by pathways different from whisker growth. The amount of intermetallics is mainly a property of the substrate. It will therefore be determined how much intermetallic is formed depending on time, temperature, and substrate.
With the introduction of legislation, the RoHS-directive (Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment, 2002/95/EU), the date of lead-free electronics is now fixed as 1 July 2006. The change from tin/lead compounds to lead-free ones creates a potential reliability risk at electronics.
Specific Goals in 2005
1. The influence of whiskers on the reliability of electronics
The influence of whiskers on the reliability of electronics has studied by collecting information from Finnish and international research projects. At the same time the changes of materials in electronics due to the RoHS-directive has studied. This has partly done with participation in international conferences.
2. Participation in IEC TC45 standardisation work
The development of the new IEC-standard, IEC 62342: Nuclear power plants – Management of aging of nuclear power plant instrumentation and control and associated equipment (45A/441/NP), has continued.
Deliverables
Palmén, H., Turtola, A., Hossi, H. Influence of Whiskers to Reliability of Electronics (in Finnish), VTT research report, NRO VTT-R-00856-06, Espoo, 31.1.2006, 15 p.
IEC 62342 Ed. 1.0 B CCDV Nuclear power plants – Instrumentation and control important to safety – Management of aging.
PNW 45A-597 Ed. 1.0 E PNW Methods for nuclear power plants – I&C systems important to safety – Management of aging of electrical cable systems.
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in Finland and internationally has been discussed and reported in the reference group meetings in some extent.
2.5.1 Organisatorial culture and management of change (CULMA)
The main objective of the CulMa-project (2003-2006) is to increase the understanding of the effects of organizational factors on nuclear safety. The project aims to produce knowledge of the effects of organisational culture, organisational changes and the different ways of organising work on the safety of nuclear power production. The project continues the work done in the FINNUS/WOPS-project to develop a methodology for contextual assessment of organisational culture (CAOC) in safety-critical environments. The practical goal is to develop methods and models with which to take organizational factors into account e.g. in change situations and development initiatives so that all of the criteria for an effective organisation (safety, productivity and health) are adequately considered. The project is carried out in case studies in close cooperation with the power plants.
Specific goals in 2005
In 2005 the work in the CulMa-project aimed at studying the safety effects of organizational changes at NPPs and at studying and developing the learning of newcomers in maintenance organizations. Also, aim was to model the demands of work and organizational culture at the department of Power Plant Engineering at TVO. These aims promoted the clarification of the effects of organizational factors on nuclear safety.
Deliverables in 2005
• The project delivered in 2005:
• One Finnish language book on the special characteristics of safety-critical organizations
• NKS report on management of change in the nuclear industry
• Two non-scientific communications (Kunnossapitolehti and ATS Ydintekniikka)
• Two internal reports to the power plants on the results of the case studies
• A scientific article on the assessment of maintenance culture at FKA and TVO
• An edited book on safety management in Nordic countries together with Swedish and Norwegian editors
• Also three conference presentations have been held, one scientific article has been submitted, and one full paper and one abstract to conferences to be held in 2006 have been submitted.
• Case study on the training and socialisation of newcomers in maintenance at TVO (2004-2006) has been continued. Results and recommendations concerning the change in attitudes, change in conceptual understanding, experiences of the training has been
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presented to the training department of TVO and to the maintenance unit in a confidential report.
• Two year case study on organizational culture at the Power Plant Engineering at TVO was started. Interviews and document analysis were done and the schedule for 2006 was planned together with the project group.
• Case study on process thinking in nuclear power plants has been started. Production management process at Loviisa NPP was modelled together with the plant personnel.
Several meetings were held were the process models have been iterated. The process modelling has been focused on the current way of working first. The pros and cons of process thinking in the nuclear industry have been identified.
• Co-operation with Mälardalen University has been continued within the NKS- R/MainCulture project. Organizational changes and their safety consequences in Nordic NPP maintenance units have been analysed and a final report on managing change in the nuclear industry has been written. The report will be published in the NKS-series.
• The project personnel have also participated in the NKS-R/Safety Management Network co-ordinated by Prof. Ola Svenson and co-authored a book on Nordic perspectives to safety management (Svenson et al. 2006). Two articles have also been written to the book by the CulMa personnel.
2.5.2 Disseminating Tacit Knowledge and Expertise in Organizations (TIMANTTI)
The main objectives of the TIMANTTI-project is to enhance, increase and develop the sharing of tacit knowledge between experienced and inexperienced employees, to motivate employees of different ages to share knowledge, and to identify, understand and develop factors affecting the effectiveness and successfulness of knowledge sharing.
Specific Goals in 2005
The specific goals for the year 2005 were to create new understanding of the role and content of tacit knowledge in two selected case units and develop and implement methods for preserving it by enhancing knowledge sharing between experts and novices. In addition the goal was to evaluate the usability of these methods and create new knowledge about the preconditions of effective and useful tacit knowledge sharing in NPP context.
Deliverables in 2005
• A case study in Loviisa was carried out, including pre-interviews, a workshop with the interviewees, implementation of methods supporting knowledge sharing and follow up group discussions in order to evaluate these methods and develop them further. The results were reported in the workshop and as a written report.
• A case study in Olkiluoto was carried out, including pre interviews, a workshop with the interviewees, implementation of methods supporting knowledge sharing and follow
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up group discussions in order to evaluate these methods and develop them further. The results were reported in the workshop and as a written report.
• Altogether four conference papers were written and presented in two workshops:
• INAC 2005 – International Nuclear Atlantic Conference, NKM Workshop
• CSNI Workshop on Better Nuclear Plant Maintenance: Improving Human and Organisational Performance
• Two journal articles were approved for publishing:
• Kuronen, T. & Rintala, N. (2005). The Classification of Knowledge and Expertise in Finnish Nuclear Power Plants. International Journal of Nuclear Knowledge Management, 2 (2), in press.
• Rintala, N. & Kuronen, T. (2005). How to Share Tacit Nuclear Knowledge.
International Journal of Nuclear Knowledge Management, 2 (2), in press.
• A visit from Forsmark HR department was realized in order to outline possibilities for research co-operation.