Nuclear Fabrication – Stringent Quality Requirements & Challenges

By G.K. Pillai, Managing Director & CEO, Walchandnagar Industries Ltd.

Why are quality requirements so stringent for nuclear power generation equipment?

It is well-known that nuclear power is generated due to a controlled nuclear chain reaction in which the nucleus of a heavy atom like Uranium-235 or Plutonium-239 is split by neutron and heat is released. The released heat converts water into steam and the steam turbine runs the generator to produce electric power. It is thus critically important to control the nuclear chain reaction and avoid release of uncontrolled heat energy, blast and radioactive waste in the form of gases and debris (nuclear explosion). It is necessary that Nuclear Power Plants and Facilities are designed and constructed with the highest possible quality standards and operated with extreme care so that safety of the plant is always assured and any kind of accidental damage is avoided.

From an industrial standpoint how do we address these requirements while executing work related to fabrication of such equipment?

Primarily the framework of the “Quality Assurance Program (QAP)” addresses the core issue of such stringent quality requirements.

The features of a QAP are as follows:

1. Design Control – Measures are established to assure that applicable regulatory requirements and the design basis are correctly translated into specifications, drawings, procedures, and instructions. These measures include provisions to assure that appropriate quality standards are specified and included in design documents and deviations from such standards are controlled.
2. Procurement document control – Applicable regulatory requirements, design bases, and other requirements which are necessary to assure adequate quality are suitably included or referenced in the documents for procurement of material, equipment, and services.
3. Instructions, procedures and drawings – Activities affecting quality are prescribed by documented instructions, procedures, or drawings of a type appropriate to the circumstances and are accomplished in accordance with these instructions, procedures, or drawings. Instructions, procedures and drawings include appropriate quantitative or qualitative acceptance criteria.
4. Document Control – Measures are established to control the issuance of documents, such as instructions, procedures, and drawings, including changes thereto, which prescribe all activities affecting quality. It is thus assured that documents, including changes, are reviewed for adequacy and approved for release by authorized personnel and are distributed to and used at the location where the prescribed activity is performed. Changes to documents are reviewed and approved by the same organizations that performed the original review and approval unless the applicant designates another responsible organization.
5. Control of Purchased Material, Equipment, and Services – Framework and workflows are established to assure that purchased material, equipment, and services, whether purchased directly or through contractors and subcontractors, conform to the procurement documents. This also includes provisions, as appropriate, for source evaluation and selection, objective evidence of quality furnished by the contractor or subcontractor, inspection at the contractor or subcontractor source, and examination of products upon delivery.
6. Control of Special Processes -All special processes, including welding, heat treating, and non-destructive testing, are controlled and accomplished by qualified personnel using qualified procedures in accordance with applicable codes, standards, specifications, criteria, and other special requirements.

7. Inspection – A program for inspection of activities affecting quality is established and executed to verify conformance with the documented instructions, procedures, and drawings for accomplishing the activity. Such inspection is performed by individuals other than those who performed the activity being inspected. Examinations, measurements, or tests of material or products processed are performed for each work operation where it is necessary to assure quality. If inspection of processed material or products is impossible or disadvantageous, indirect control by monitoring processing methods, equipment, and personnel are provided. Both inspection and process monitoring shall be provided when control is inadequate without both.
8. Test Control – A comprehensive test program is drawn up to ensure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service is identified and performed in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents. The test program shall include, as appropriate, proof tests prior to installation, preoperational tests, and operational tests during nuclear power plant or fuel reprocessing plant operation, of structures, systems, and components. Test procedures shall include provisions for assuring that all prerequisites for the given test have been met, that adequate test instrumentation is available and used, and that the test is performed under suitable environmental conditions. Test results are documented and evaluated to assure that test requirements have been satisfied.
9. Nonconforming Materials, Parts, or Components – Measures are established to control materials, parts, or components which do not conform to requirements in order to prevent their inadvertent use or installation. These measures include, as appropriate, procedures for identification, documentation, segregation, disposition, and notification to affected organizations. Non-conforming items are reviewed and accepted, rejected, repaired or reworked in accordance with documented procedures.
10. Handling, Storage and Shipping – Adequate measures are taken to control the handling, storage, shipping, cleaning and preservation of material and equipment in accordance with work and inspection instructions to prevent damage or deterioration. Wherever necessary for particular products, special protective environments, such as inert gas atmosphere, specific moisture content levels, and temperature levels are specified and provided.

Challenges faced by industry and how they are being overcome:

1. Domain knowledge: The personnel working on critical nuclear equipment have to have domain knowledge so that they can understand nuclear requirements, the consequences of failures of equipment in service and ensure right quality equipment is produced without any compromise.
2. Basic Qualifications and Training: The personnel are chosen with adequate basic qualifications and then trained in the required specialization by qualified organization and teachers with due exams and certifications.
3. Facilities: The high quality work demands high quality and appropriate machine tools, heat treatment furnaces, dust -free rooms, cranes, manipulators, jigs, fixtures, test facilities, Non- Destructive (NDT) and destructive testing facilities in-house or nearby, documentation, etc.
4. Developmental work: Most of the work for the new nuclear projects is first of its kind and involves a great amount of developmental work. Many a time the nuclear authorities cannot estimate the extent of developments required. This leads to considerable amount of extra work and time and cost over runs.
5. Transportation: The fabricated equipment need to be transported safely to Nuclear Plant site. Road transportation is adequate for small size equipment but for Over Dimensional Consignments (ODC) it is a challenge due to inadequate roads, bridges, heavy population, overhead wires / cables, trees, etc. Sea transportation is the alternative for long distance transportation but adequate nearby sea port is required which is expensive and not available in many land based interior workshops.
6. Remote Locations of Nuclear Facilities: The resources available at new plant site are generally inadequate and pose problems for installation of equipment.
7. Financial viability: Due to high quality requirements and challenges faced above, the cost of equipment becomes high. Also fabrication of nuclear equipment is a skill which is developed over a period of time with sustained efforts. With the “L1” philosophy that is followed in most tenders as well as lack of adequate visibility of orders in pipeline, the investments required to be committed are quite high without an underlying guarantee of business.

About Walchandnagar Industries Ltd :
Walchandnagar Industries Ltd., which is a 106 -year old diversified conglomerate, operates in various core sectors of the economy and has presence in both EPC (Sugar Plant & Co-generation Equipment and Cement Plant Equipment) and Niche – Manufacturing (Defence, Aerospace, Missiles, Nuclear, and Gearboxes) businesses. It has been a primary equipment supplier for India’s Nuclear Power Program (through its association with Nuclear Power Corporation of India ) since almost four decades and has supplied various core and critical equipment required in the reactor area of Nuclear Power Plants like Calandria, Heat Exchangers, End Shields, etc.

For more information
Web: www.walchand.com