Office for Nuclear Regulation

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Heysham 2 - SBI20 - Liquid Radwaste

Executive summary

Purpose of intervention

The purpose of this intervention was to conduct a system based inspection (SBI) of EDF Energy Nuclear Generation Ltd's Heysham 2 Power Station in relation to the liquid radwaste system. This was undertaken as part of a series of planned interventions that are listed in the Heysham 2 Integrated Intervention Strategy 2016/2017.

The inspection was undertaken by the ONR Nominated Site Inspector, a mechanical engineering specialist inspector and a nuclear liabilities specialist inspector. This was a joint inspection with the Environment Agency and it was observed by a representative from the Department of Business, Energy and Industrial Strategy.

Interventions Carried Out by ONR

We performed a safety case informed system based inspection (SBI) of the liquid radwaste system. Through examination of this system, compliance inspections were performed against Licence Conditions 10 (training), 23 (operating rules), 24 (operating instructions), 27 (safety mechanisms, devices and circuits), 28 (examination, inspection, maintenance and testing) and 34 (leakage and escape of radioactive material and radioactive waste). The inspections were based on sampling the implementation of the arrangements in place at the station against each licence condition. The objective of the inspection was to determine whether the Licensee's arrangements were in accordance with the system's safety case requirements.

In addition to the SBI, we undertook compliance inspections against Licence Conditions 32 (accumulation of radioactive waste) and LC34 leakage and escape of radioactive material and radioactive waste sampling the implementation of the Heysham 2 arrangements against this licence condition.

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

From this inspection, we judged that overall the safety provisions applicable to the liquid radwaste system met the requirements of the safety case.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

An SBI of the liquid radwaste system was carried out to judge the adequacy of the implementation of the station arrangements in place to ensure that relevant equipment can perform its requisite safety function. In deciding whether this safety system has been adequately implemented, we inspected compliance with the licence conditions detailed above.

During the course of this SBI it was found that Heysham 2 Power Station has arrangements to ensure that the liquid radwaste system inspected is maintained and, as necessary, operated in accordance with its safety case. The arrangements examined complied with NGL's legal duties based on of the areas sampled during the inspection. The inspection identified potential areas for improvement; however, none gave rise to significant concern. Due to the limited significance of these observations, we were content that NGL will address these through its own arrangements.

On the plant walkdown, we were satisfied that housekeeping was generally of a good standard. We identified two examples where low level waste was not being stored in line with Heysham 2's own arrangements; however, staff responded immediately to rectify this.

In summary, the SBI of the liquid radwaste system inspected, for Licence Conditions 10, 23, 24, 27, 28 and 34, is rated as GREEN on the basis that relevant good practice was generally met and identified deficiencies in compliance arrangements were relatively minor.

It was noted that the Radioactive Waste Safety Case is produced and managed at a corporate level, rather than a site level. The nuclear liabilities specialist inspector has agreed is to discuss the suitability of this arrangement with the ONR corporate inspector.

For the LC32 and LC34 compliance inspections, we examined the station's compliance against its primary implementation arrangements. We considered the station's arrangements for the management of high efficiency particle arrestance filters and low level waste (LLW) sludges.

For the LC32 compliance inspection we identified that records for the tracking of LLW sludge from generation, through processing to produce a final disposal drum could be improved. This was considered a minor non-compliance an ONR level issue 4711 has been raised to follow its progress.

For the LC34 compliance inspection we were satisfied that suitable and sufficient arrangements were in place to ensure adequate control and containment of radioactive material and radioactive waste, and therefore the LC32 and LC34 compliance inspections have been assigned a rating of Green.

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

Conclusion of Intervention

After considering the evidence examined during the sample inspections undertaken against Licence Conditions 10, 23, 24, 27, 28 and 34 we concluded that the licensee complied with its legal duties regarding the liquid radwaste system inspected and met the requirements of the safety case.

After considering the evidence examined during the sample inspection undertaken against Licence Condition 32 and 34 we concluded that the licensee complied with its legal duties, a minor non-compliance within the LC32 arrangements was identified. A single ONR issue has been raised (ONR issue 4711) to monitor progress of the action raised.

There are no findings from this intervention that could significantly undermine nuclear safety.