Sizewell A - Ponds System Inspection
- Site: Sizewell A
- IR number: 16-073
- Date: July 2016
- LC numbers: 10, 23, 24, 28, 34
Purpose of intervention
The Office for Nuclear Regulation (ONR) undertakes all regulatory interactions with the Sizewell A (SZA) site licensee, Magnox Limited, against an inspection schedule defined by ONR's Sellafield, Decommissioning, Fuels and Waste Programme.
In accordance with the Sizewell A integrated inspection schedule, a system based inspection (SBI) of System S3.3, Ponds and effluent control Systems was planned and undertaken in July 2016. The purpose of this inspection is for ONR to examine whether the licensee's safety case claims in respect of this system important to safety have been adequately implemented. The intervention was carried out as a joint inspection with the Environment Agency to provide a more efficient and effective means of regulation of this area.
Interventions Carried Out by ONR
I carried out a systems inspection of S3.3, Ponds and effluent control Systems. The SBI is undertaken against the following Licence Conditions (LCs):
- LC 10: Training
- LC 23: Operating rules
- LC 24: Operating instructions
- LC 27: Safety mechanisms, devices and circuits
- LC 28: Examination, inspection, maintenance and testing
- LC 34: Leakage and escape of radioactive material and radioactive waste
In addition to the planned inspections I also attended number of meetings. These included the following topics:
- Review of ONR's outstanding regulatory issues and actions for SZA
- Review of the licensees close-out of Active Effluent Treatment Plant (AETP) actions
- Meeting with the licensees internal regulator to discuss internal inspection programmes and key issues/findings
Explanation of Judgement if Safety System Not Judged to be Adequate
Key Findings, Inspector's Opinions and Reasons for Judgements Made
The Systems inspection of S3.3, Ponds and effluent control Systems showed that the plant was being adequately operated and maintained in accordance with the licensees' arrangements and meets the requirements of the safety case.
For each of the licence conditions inspected I concluded that:
- LC 10 (Training) - Examination of training and SQEP records for a sample of the personnel involved in the operation, supervision and maintenance pond systems confirmed that the essential training requirements for each role profile with all essential training was in date, and the necessary appointments and authorisations were in place. I therefore assigned an IIS rating of Green (adequate) for LC10 on this inspection.
- LC 23 (Operating rules) - There are no approved Operating Rules applicable to the pond systems. However, a number of dose reduction measures were identified which were important limits in maintaining control and containment of radioactive materials. As such I targeted these limits and conditions of operations and confirmed operations, monitoring and adherence with them. I assigned an IIS rating of Green (adequate) for LC23 to this inspection.
- LC 24 (Operating instructions) - I sampled the routine checks by plant operators and associated maintenance tasks undertaken of the pond systems, and confirmed that both the operating and instructions were in place and being followed. I assigned an IIS rating of Green (adequate) for LC24 to this inspection.
- LC 27 (Safety mechanisms, devices and circuits) - There are no Safety Mechanisms associated with pond control systems, as all safety measures are now engineered passive features (such as syphon breaks and containment structures). I therefore rated LC27 as N/A (Not Applicable) for this inspection.
- LC 28 (Examination, inspection, maintenance and testing) - I examined the maintenance schedule and maintenance records in support pond and effluent control systems. This confirmed the licensee was complaint with its arrangements and all maintenance was within its required period. I assigned an IIS rating of Green (adequate) for LC28 to this inspection.
- LC 34 (Leakage and escape of radioactive material and radioactive waste) - I examined a number of inspection records and system health report associated with the Ponds and AETP civil containment structures. Identified defects were followed through to show how asset care is managed, plant health is maintained and safe operations justified. I also examined the improvements carried out in the AETP to improve containment. I assigned an IIS rating of Green (adequate) for LC34 to this inspection.
Overall, I concluded that the arrangements and their implementation on the Pond systems from an operational and civil engineering perspective met the requirements of the safety case and judged these to be adequate through the course of the inspection.
In addition to the planned systems inspection I also attended number of meetings with the licensee as identified in section 1.2. details of these meetings are recorded in the main body of the report, but no safety concerns were identified:
Conclusion of Intervention
Overall I judged that the systems adequately meets their safety case functions and are being adequately operated in accordance with the safety case. I found no issues that significantly affect safety, or that required further regulatory intervention.
Based on the inspection findings I judged that an inspection rating of GREEN (adequate) was appropriate for the SBI for System S3.3, Ponds and effluent control Systems system and for each of the relevant Licence conditions covered.