B205 System Inspection 'Steam' and Routine Interactions
- Site: Sellafield - Magnox
- IR number: 14-113
- Date: September 2014
- LC numbers: 10, 23, 24, 27, 28, 34
Purpose of intervention
This intervention was undertaken on 22 – 25 September 2014 at Sellafield Limited’s Sellafield nuclear licensed site in Cumbria.
Inspection of Licence Condition (LC) compliance at nuclear licensed sites is an important aspect of ONR’s activities. ONR’s Sellafield Programme has defined a programme of system inspections and LC compliance inspections to be undertaken on the Sellafield site that focuses on the aspects of SL’s operations that are most important to safety. The present system inspection, identified on ONR’s PP4 inspection plan which covers Sellafield Limited’s Magnox Operating Unit, is part of that programme.
Interventions Carried Out by ONR
The intervention comprised:
- undertaking a system inspection of system 1.08a ‘Steam’ within the Magnox Reprocessing Plant; and
- undertaking a number of meetings comprising routine regulatory interactions.
The safety significant use of steam within the Magnox Reprocessing Plant is to provide the motive force for steam ejectors to move nuclear materials between plant vessels. The system inspection sought to determine whether the Magnox Reprocessing Plant steam ejector system meets the requirements of the safety case and is adequate. The implementation of the licensee’s arrangements for the following LCs was tested during the system inspection:
- 10 ‘Training’
- 23 ‘Operating Rules’
- 24 ‘Operating Instructions’
- 27 ‘Safety Mechanisms, Devices and Circuits’
- 28 ‘Examination, Inspection, Maintenance and Testing’
- 34 ‘Leakage and Escape of Radioactive Material and Radioactive Waste’
Explanation of Judgement if Safety System Not Judged to be Adequate
Based on sampling inspection, the steam system of the Magnox Reprocessing Plant was judged to be adequate.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
For the steam system of the Magnox Reprocessing Plant I judged the following IIS ratings to be appropriate:
- LC10 – IIS rating 3 (adequate): I confirmed that the training material specific to undertaking maintenance activities on steam plant is appropriate and that, based on my sample, training of individuals is up to date and individuals were adequately trained. I judged an IIS rating of 3 (adequate) to be justified. I did not judge a higher IIS rating to be appropriate because there is potentially a mismatch between guidance in the training material and operational practices which I have referred to ONR’s conventional safety function.
- LC23 – IIS rating 2 (good standard): I confirmed that the safety case specifies limits and conditions with respect to the operation of steam ejectors in the form of an operating rule, and that these limits and conditions are clearly specified in appropriate instructions. The compliance trail for the operating rule from the safety case through instructions to plant check sheets was very clear and I did not note any deficiencies. Based on my sampling inspection, I judged an IIS rating of 2 (good standard) to be justified.
- LC24 – IIS rating 3 (adequate): I sampled a range of operating instructions, maintenance instructions and alarm response instructions. I judged them to be clear and unambiguous, and related to ensuring compliance with the limits and conditions derived from the safety case. I judged an IIS rating of 3 (adequate) to be appropriate against LC24 ‘Operating Instructions’. A higher rating may have been appropriate if there had not been a discrepancy between an emergency instruction and the safety case. In this instance I did not consider a lower rating proportionate however, because the discrepancy had been identified by the licensee in advance of my inspection.
- LC27 – IIS rating 3 (adequate): I sampled a number of key Safety Mechanisms (SMs) and Safety Related Equipment (SRE). I judged an IIS rating of 3 (adequate) to be appropriate against LC27 ‘Safety Mechanisms, Devices and Circuits’ because, with the exception of one SM claimed for dissolver heating steam isolation, I found all SM and SRE to be properly connected and in good working order. The licensee had identified the discrepancies with the SM in advance of the inspection and already had plans to address the issue under its Long Term Periodic Review shortfall close-out programme. Therefore I did not judge a lower IIS rating to be proportionate.
- LC28 – IIS rating 3 (adequate): I sampled the maintenance schedule, maintenance instructions and maintenance records for key components of the system. I judged an IIS rating of 3 (adequate) to be appropriate against LC28 ‘Examination, Inspection, Maintenance and Testing’ because I found the maintenance arrangements to be in order for the sample, and I was content that the inspection regime in place was consistent with the requirements of the Pressurised System Safety Regulations. I did not judge a higher IIS rating was justified because the licensee is not undertaking inspections under lagging in the external steam pipework (this is not formally required by the PSSR but would be in line with good practice), and the lagging itself is in poor condition.
- LC34 – IIS rating 3 (adequate): I sampled the arrangements in place to detect escape of radioactivity from the Low Pressure steam condensate streams where there is potential for transfer of radioactivity between process fluids and the heating steam. I judged an IIS rating of 3 (adequate) to be appropriate against LC34 ‘Leakage and Escape of Radioactive Material and Radioactive Waste’ because I concluded adequate arrangements are in place to prevent leakage of radioactive materials, and to detect any leakage that does occur.
Based on this sample inspection, I judged that the operation of the steam system is consistent with safety case requirements, the key equipment that verifies this is available and appropriately maintained, those responsible for operations are suitably trained and that appropriate written instructions are available. I conclude the steam system meets the requirements of the safety case.
Conclusion of the intervention
Three actions were placed as a result of this intervention, I will manage their close out as part of normal regulatory interactions with the licensee. Based on the evidence gathered, no significant matters have been identified that are likely to impact on nuclear safety on the Sellafield site at this time.