Prime pagine RA2010FUS:Copia di Layout 1 - ENEA - Fusione

078
progress report
2010
Operability Studies”. After a first preliminary phase dedicated to developing the background information
required for the analysis, such as to define the scope of the analysis, appoint a team leader with approval of
ITER Responsible Officer, assemble the team to perform the HAZOP Study with approval of IO, collect
relevant information and supporting documents, review the system and define the segments of the system to
analyze and, review the ITER “Consequences of interest and hazards table”, team of experts performed the
studies in dedicated meetings by applying the following procedure:
• Review the segments of the system to be analyzed and the “Consequences of interest and hazards table” in
order to get team consensus.
• Select process variables (flow, pressure, etc.) and define operation modes to investigate.
• For each segment, evaluate the potential consequence of the deviation of the process variables by applying
guidewords.
• Determine cause(s) leading to deviation, and identify whether no cause can be determine or the condition
of the cause.
• Evaluate potential consequences and the corresponding hazards resulting from each deviation condition,
and identify whether no consequence is identified or the consequence.
• Develop detection and controls to mitigate effect of the deviation.
• Determine the residual risk associated with the cause with the identified detections and controls, (e.g.:
estimation of the likelihood of the cause occurring and the severity of the cause with the identified detection
and controls).
• Identify the corresponding residual risk (minimal, low, medium or high) by using a risk matrix.
• When the residual risk is high or medium it will be noted as an action item to review whether additional
controls and detection are needed to mitigate the hazard.
• Repeat procedure for each item: deviation of a process parameter (no, less, more, etc.) for the specific
segment; for all process variables (flow, pressure, temperature, etc.) for the specific segment; for all segments
in a section; for all sections in a system.
• Document the identified detection and control for the system.
• Assign responsible individual and due date to address action items.
• Integrate action items into detection and controls for system when complete.
The HAZOP study has been concluded by the identification of limiting conditions of operations (LCOs) for
the overall events that might induce hazardous (incidental/accidental) conditions. LCOs have been
qualitatively identified in order to collect under common categories the detections and the controls most
significant from the safety point of view.
Most of the identified events inducing hazards for the environment and the workers have been classified with
acceptable level of residual risk, as “No additional detection and/or controls needed”, and “Detection and/or
controls reasonable”. Only few events have been judged with a residual risk such to require “Review additional
detection and/or controls”. These events have been highlighted with an indication about consequences, in
terms of the plant conditions and hazards, and additional detection and/or controls required.
In this frame, ENEA developed a software tool to generate a HAZOP spreadsheet database, in agreement with
the “ITER Guide to Performing Hazard and Operability Studies”.
3.8 Broader Approach
JT–60SA
Layout study of JT–60SA coils power supplies and switching network units. According to the Broader Approach
(BA) program development, ENEA and Commissariat à l'Energie Atomique (CEA) had updated and reviewed
the layouts of the new power supplies for JT–60SA PF coils, fast plasma position control coils, toroidal field
(TF) coils and switch network units.
JT–60SA will be located at JAEA NAKA Fusion Institute. Most of the existing building, infrastructure,
available for the JT–60U devices, will be re–used for JT–60SA.