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6. MITIGATION AND REMEDIATION OF FOREIGN MATERIAL INTRUSION

6.2. Mitigation of a current foreign material

6.2.3. Detection

Before any plans, actions and efforts taken or put into place, the situation surrounding the FMI need to be properly known, understood and interpreted. This requires first a visual search and detection of the FM (i.e. an acute detection) and, if its location is not easily visible (and/or its condition cannot be absolutely known20), then a more detailed FOSAD process (i.e. a planned detection). Whether it is acute or planned, the detection process aims, as a minimum:

— Identification of FM that initially intruded and any other FMs that are generated during the FMI from the impact of that FM;

— Determination of shape, condition, location and position of FM(s);

— Determination of equipment damage from the FM(s) and by the sequence of events during FMI.

The detection of FM(s) can be initiated by directly observed/witnessed FMI or by an indication of a potential FMI, for example:

— Acute observation of FM entering the SSC, witnessed by the workers, observers, monitors, inspectors, etc., during the activity performance;

— Reporting/notification by individual(s) of a missing or lost item (or part of an item);

— Individual or work group encountering physical damage/defect while opening the SSC (e.g. gasket material is crumbling);

— Discovery of failed or damaged internal barriers or external covers that are found to be degraded or missing (for example, while the area has been left unattended);

— Materials, tools, parts, items which cannot be accounted for during FMM Log reconciliation (i.e. unresolved log keeping issues, such as the item still in the log, but not in the area or described/identified differently);

— Parts/materials that are found to be missing, damaged or defective during disassembly or reassembly of components;

— Measured anomalies in SSC operating parameters (temperature, flow, pressure, vibration, etc.) or unexpected sensory indications coming from the SSCs (e.g.

unusual/unexpected colour, odour, noise, smoke, leak), particularly when they are started, or have been running for a period, following the activity that was performed on them;

— Findings of analyses and assessment that are conducted for the characterisation of a FM and FMI event.

In addition to naked eyes, FOSAD can include various methods and tools (and associated qualification and skills), including:

20 Absolute knowledge includes not only the knowledge of FM but also of any FM that might have been generated during the event. For example, it might be a dropped adjustable wrench which has a possibility of some small parts coming apart as a result of impact from the fall.

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— Simple direct visual tools, such as mirrors, magnifiers, telescopes;

— Special confirmatory tools and analysis for internal detections, such as:

 Borescopes;

 Remotely operated video cameras;

 Radiography;

 Ultrasonic testing;

 Infrared thermography;

 Ferrography;

 Fibreoptic technology;

— Monitoring and detection systems (e.g. leak detection, vibration monitoring).

Before the FOSAD activity is implemented, a planning of the work may be necessary and a FOSAD Plan need to be prepared in accordance with the guidance, requirements and expectations provided in the FMMP administrative procedure (or by applicable implementation procedures). In some cases, such as the FM is visible and it can be confirmed that is it intact and that there is no possibility of further movement or any further impact on SSCs (which also requires an independently review and confirmation), a FOSAD Plan may not be necessary. In such cases, even the whole FOSAD process may be skipped and the FORAR process can be considered and started with appropriate review and approval.

The preparation and implementation of FOSAD Plan and its implementation are based on:

— Weighted scale of the graded approach;

— What the known and potential FMs are, including their types, materials, potential locations and forms;

— Sensitivity of the FM and its location to the movements during detection activities;

— Necessary and applicable detection methods and tools;

— Risks to components or personnel associated with detection type, process, tools and methods;

— Operability and maintainability of detection activities, such as accessibility, confined spaces, etc.

Accordingly, the specific contents of a typical FOSAD Plan include (noting that graded approach will determine its contents and scope, as well as the reviews and approvals of the plan, which are defined by the FMMP and other plant/project programmes):

— Description of the FM that is going to be searched for, including type, material, quantity, anticipated quantity, condition, shape and location of FM;

— Description of the FMI sequences, as available

— Existing equipment damage that is known or anticipated;

— Identification and description of, and options for (including options’ ranking based on, among others, safety, ALARA, schedule, resources, risks, hazards, retrievability of FM):

 Detection methods and tools to be used, including the location and type of conduct, e.g. infield/remote, intrusive/non-intrusive, continuous/intermittent;

 Detection activity areas, SSCs, and pathway, including systems to be opened, paths to be used, locations for system entry/intrusion, e.g. manholes, drains, vents, and starting with the systems and flow paths/locations with the high possibility or probability of finding the FM;

— Entry conditions and prerequisites for FOSAD procedure/process/activity implementation;

— Anticipated/known hazards, risks and consequences associated with detection methods, tools and activities regarding:

 Industrial, radiological and nuclear safety;

 Equipment reliability;

 Creation of new and additional FM;

 Existing equipment damage and creation of further damages;

— Measures to eliminate or minimise FM risks and hazards during the activity, for example, for preventing:

 Further spread or transport of FM during recovery activities;

 Further FM risk and hazards, as well as new targets and paths, during detection activities;

 Detection tools from becoming FM themselves (as there are several OPEX on broken or stuck tools, for example lost camera lens in a steam generator header, as one plant representative indicated);

— The necessary activities for locating FM(s) including all the measures to be taken for other programmatic and technical requirements, expectations and actions, such as:

 Temporary SSC and equipment modifications (opening, disassembly, etc.) for accessibility needs, including the FMM/FMC measures around those SSCs and equipment;

 Operability, availability, functionality of SSCs that will be modified/worked on for the implementation of FOSAD activities, including tagout;

 Radiological protection and ALARA assessment;

 Environmental and confined space conditions assessment;

 Normal and emergency ingress/egress/movement paths for personnel and equipment;

 Power and other sources needed and their configuration;

— The schedule and resources to be utilised for the search and detection, including:

 Qualifications, knowledge, skills and competencies needed for the activity;

 Training needs (including mock-ups) of personnel performing the retrieval;

— Methods for the monitoring and, if necessary, maintenance of detection equipment and their status during the retrieval efforts;

— Exit conditions from FOSAD and entry to FORAR process and activities, including hold points to wait for needed parallel assessments, such as the analysis, characterisation and confirmation of detected materials (i.e. confirmation of FM type, material, quantity, anticipated quantity, condition, shape and location);

— Possible ‘Plan B’ and readiness to act on it.

It is also important (and a good practice) to collect as much information and knowledge about the FM and FOSAD evolution during the conduct of the FOSAD activities, as such information could be utilised in parallel or subsequent analyses to support FORAR, FORAA and event investigations. More importantly, the collected information and knowledge during FOSAD will

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support future activities and the improvement of FMM and FMMP. This information and knowledge can be obtained, collected and preserved by various methods and tools including photographs, videos.