3. FOREIGN MATERIAL MANAGEMENT THROUGHOUT NUCLEAR POWER
3.3. Construction phase
The construction (and reconstruction3) stage includes erection of the buildings and installation of SSCs, as well as both onsite and offsite manufacturing/fabrication, transportation, storage and assembly activities of systems.
Operating experience shows that the construction/reconstruction stage is very critical with respect to susceptibility of FMI events and makes the control and management of FM essential (and also challenging) primarily due to:
— Many systems and components being open and worked on;
— Multiple activities are being performed in the close proximity of each other;
— Wide variety and number of tasks and environmental conditions generating and moving potential FMs at the work zones and around the site;
— Large number of personnel from different companies, qualifications, backgrounds, even sometimes different languages, conducting activities simultaneously, independently or intermittently.
A trend analysis from the event reports from the IRS and the operating plant reports demonstrates that:
“Large majority of the latent foreign material associated events during the operation can be traced back to a lacking or the deficiencies of FMM during construction, primarily involving items being left over in the systems. The items which are the most affected by construction, manufacturing or commissioning deviations are I&C (19%), electrical components (17%), welds (14%), valves (10%) and pipes (9%). More importantly, the average detection time of the initial defect is about eight years after the start of commercial operation and more than 75% of the events are discovered by luck or coincidence [19]. Among those, majority of foreign material discovered in the SSCs during the operations can be traced back to construction activities lacking adequate controls and barriers for foreign material, for example, construction or personal items were left in the work area or systems that would have been prevented by comprehensive FMMPs that are typically followed during operations”.
This also emphasises the necessity of detecting the foreign material during the manufacturing and at the construction stage, as it may be difficult to identify them during operation.
During the consequent operation of the plant, reconstruction of the facility, such as refurbishment, major equipment replacement, site upgrades, major structural changes/
additions, may be initiated, performed and/or implemented by the operating organisation and/or other external construction organisations. Again, activities during these major changes can be as nearly complex as the original construction (i.e. ‘reconstruction). Therefore, some of those major plant changes and associated activities conducted during operation phase will typically be subject to the same FMM and FMMP challenges as in the initial construction. Some of those
3 Herein, the term ‘reconstruction’ of the facility indicates very extensive and complex changes to the operating facility, such as refurbishment, major equipment replacement, major structural changes/additions and site upgrades.
32
changes during operation phase and the FMM considerations are further discussed in Section 3.5.
Also, during the construction/reconstruction phase, design modifications may be initiated and implemented continuously (either by the responsible designers or by the owner organisation, or both). The design changes could also include the consideration of ‘design for FMM/FMC’, which may require designers’ review and approval for installation and changes subject to FMM requirements and engineered FMCs and keeping records of FMM issues (including a list of, if any, FM that is justified as part of a system, as mentioned in see Section 2.4.5).
3.3.1. High importance areas for foreign material management during construction phase
During the construction phase, the emphasis of the FMMP is on the prevention, protection, exclusion and mitigation processes, particularly during planning and executing activities.
Typical situations in FMM that are observed during construction phase, and particularly require attention, include:
— Loose parts falling into system opening of SSCs, such as, pipes, vessels, valves during installation;
— Objects left in the components during manufacturing in lack of cleanliness specifications or contractor’s insufficient understanding of quality control (QC) requirements;
— Leftover construction and personal material in and around SSCs;
— Improper protection of equipment from foreign material ingress paths during packing, transportation and temporary storage;
— Improper removal of internal or external packaging materials, foreign material protection devices, protective lubricants or preservation chemicals and so forth from installed components;
— Contamination of systems by debris produced and carried from nearby activities;
— Need for effective system flushing and cleaning to remove debris from the SSCs where/when it could not be prevented.
3.3.2. Involvement in and tasks for foreign material management during construction phase
Early in the construction phase, the owner/operator organisation, i.e. utility, is formed and assumes a key (and gradually expanding) role in the development and implementation of the nuclear power plant project — as a responsible organisation for the plant. Within this owner/operating organisation, a core oversight group is also established (as an internal organisation/group of owner’s coordinators, inhouse and contractor’s experts) in order to assess the adequacy of plant construction with respect to verification of meeting or exceeding the owner’s requirements and needs, including activities where FMM and FMCs are often needed and utilised.
Therefore, all organisations need to be aligned with the FMM requirements and expectations under a common FMM policy and commitment of the owner organisation. Leaders at all levels in the construction organisations are to promote and demonstrate an effective FMM culture and practices (see Section 4.3 and Section 5.3). As the foundation of such understanding and alignment, each entity, their departments, work groups and individuals involved in the construction activities need to be aware of the potential consequences of their activity with
respect to acute and latent impacts of FM on the future plant and its SSCs, and more importantly, with the later safe and efficient operation of the NPP in mind.
As such, it is important that personnel of the owner/operating organisation overseeing and supervising the construction activities need to maintain a close contact with the vendors and other contractors. Maintaining a close contact will ensure that the specific opinions, expectations and requirements of the owner/operating organisation within the management system, are communicated, expressed and represented in order to be given due considerations in the construction activities towards successful operation. This is very essential since the owner organisation will become the operating organisation upon the issue of operating licence and will assume all responsibility for safe and reliable operation of a plant that is not to be adversely impacted by FM.
Accordingly, the FMM/FMC during manufacturing and construction requires clearly defined (and agreed by all parties) FMM requirements, expectations, roles and responsibilities for the performance, supervision and oversight of construction and other activities of all involved groups — including suppliers, manufacturers and constructors, employers and contractors.
In order to ensure that SSCs are manufactured, installed and left as ‘free of foreign material’, the manufacturing and construction activities need to be conducted in accordance with a management system and all aligned FMM programmes and policies of construction entities.
Such a framework would require, regardless of the vendor company size or country, among others:
— A comprehensive and common FMM policy, commitment and strategy put in place by the owner/operating organisation to prevent FMI events by any/all parties involved in the construction and manufacturing activities;
— Collective awareness of the possible cross effects accomplished by common policy requirements, expectations and goals anchored by the site management and integrated activity planning by the project work control organisation(s);
— Verification of the programmes, processes and procedures, particularly those for associated quality assurance/quality control (QA/QC), of all involved entities by the owner/project organisation;
— A management system in place and includes FMM aspects in the inspections, validations, problem identification and, when events and/or programmatic and behavioural deficiencies are noted, the corrective action programme (CAP) and processes;
— Approval of the vendor’s quality assurance programme (QAP), as well as the FMMP, which may require:
Performance of a shop floor and process survey of the manufacturers at their locations;
Confirmation of vendor’s effective identification and analysis of FM hazards, risks and impact during entire manufacturing process, from raw material purchase and receipt to packing and shipping processing, such as utilisation of a hazard analysis and critical control points (HACCP) plan, that identifies critical points in manufacturing process that require FMM and FMC;
— Purchasing and vendor selection requirements of FM sensitive SSCs and parts (e.g.
valves, pumps, electrical, electronic and I&C equipment and components, pipes/tubing, fittings/flanges/gaskets, expansion joints, pipe supports), including compliance with
34
specified standards and codes as in order to accept and approve QA/QC plans or programmes;
— Methods and tools to inspect in and around SSCs and equipment, such as direct visual, camera, borescope, x-ray or other applicable and assuring detection methods and, as applicable, to clean (e.g. flush, sweep, wipe, etc.), at the end of activities.
As discussed in Ref. [19], this validation and associated second party verification of ‘foreign material free’ conditions of SSCs (and associated second party verifications by oversight, e.g.
QA/QC, personnel who are either from the construction contractor organisations or owner/operating organisation, or both) need to be strictly performed and recorded by complete and formal documentation. Based on the lessons learned, it is strongly recommended by the industry experts to perform such activities, for example from cleaning, flushing, inspection activities, with same quality process (including independent verification, validation and documentation) to prevent existence of any leftover foreign material in all of the SSCs, not only in the required (e.g. safety related) SSCs. This is an important practice for successful plant performance during operation, in addition to the safe operation.
It is also very important that the future plant operating organisation is provided with sufficient data and records needed for subsequent improvement of the FMM programme, processes and procedures. As such, the personnel from the plant operating organisation needs be involved and/or informed (and in control, when possible) of the methods, tools, findings, learnings, issues, measures and countermeasures, as well as the events, near-misses, close calls and associated preventive and corrective actions. This will ensure that all FMM elements can be taken into account when SSC or task specific FMMP processes and procedures, including the operation, maintenance, surveillance and test procedures, are prepared for use in operation phase.