Executive summary
Date(s) of inspection:
February 2026
Aim of inspection
The DEL chillers were selected for inspection using a risk informed approach. The DEL chillers are nuclear safety class 1 components, meaning they are considered important to nuclear safety.
The aim of this inspection was to sample NNB GenCo’s (NNB) arrangements under licence conditions (LC) 12, LC 14, LC 17 and LC 19, to gain confidence that the DEL chiller components delivered to the HPC site will be fit for purpose and fulfil their safety case requirements.
The inspection was timed to align to the factory acceptance testing (FAT) of the DELm1/4 chillers at Friotherm’s test bed facility.
This was a cross specialism inspection involving mechanical and control and instrumentation specialisms.
Subject(s) of inspection
- LC12 - Duly authorised and other suitably qualified and experienced persons - Rating: GREEN
- LC14 - Safety documentation - Rating: GREEN
- LC17 - Management systems - Rating: GREEN
- LC19 - Construction or installation of new plant - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
This was a planned compliance inspection delivering intervention H25-76, Hinkley Point C (HPC) DEL chiller manufacturing assurance.
The DEL chillers provide cooling to the DEL safety chilled water system, which itself cools various Heating, Ventilation and Air-Conditioning (HVAC) systems, supporting equipment which delivers important nuclear safety functions. The DEL chillers are classified as nuclear safety class 1 components.
The DEL chillers are designed, manufactured and tested by Friotherm GmbH, a tier 1 supplier to the HPC licensee, NNB GenCo Ltd (NNB). The inspection was carried out over two days at Friotherm’s facility in Weißensberg, Germany. During the inspection the DELm1/4 chillers were undergoing factory acceptance testing (FAT) using Friotherm’s test bed facility, whilst DELm2/3 and Unit 2 DELb chillers were under construction in the factory.
Overall, the evidence sampled provided confidence that adequate arrangements are in place. I provided advice for consideration by NNB relating to requirements traceability and the timing of control and instrumentation (C&I) integration testing with the chillers.
Conclusion
Throughout the inspection I observed a good level of knowledge from all participants, who demonstrated positive behaviours and were open and transparent about the matters discussed. Friotherm staff were consistently professional, understood the importance of nuclear safety, and were clearly committed to the delivery of a good product.
The chillers observed in the factory were in good condition, and the test bed facility is capable of fully exercising them on load. This gives confidence the chillers will be fit for purpose on delivery to HPC.
I judge that an inspection rating of GREEN (no formal action) is appropriate for LC17: management systems.
The focus of the LC17 aspects of the inspection was the quality management arrangements (processes) relevant to the control of the DEL chiller manufacture and test. I am broadly content that adequate processes are in place to manage these activities.
I have provided advice to NNB to consider whether integration testing of the DELm2/3 and DELb chillers with their non-Friotherm scope local I&C cabinets could be brought forward, to mitigate the risk of identifying a need for modifications once the chillers are already on site. However, I am content that the need to carry out this integration testing has been recognised.
Based on my sampling during the inspection, and an NDE verification follow up meeting after the inspection, I am content the processes for the control of welding activities are adequate, and that NNB have provided adequate technical oversight to ensure both welding and NDE capability are appropriated verified.
LC17(2) requires the licensee to “implement adequate quality management arrangements in respect of all matters which may affect safety.” I consider the lack of an RTM as specified in the CQAP is a shortfall in the implementation of a process which affects safety. Whilst this instance is covered by an existing open point, I have included advice to consider the broader adequacy of process implementation across other systems.
I judge that an inspection rating of GREEN (no formal action) is appropriate for LC 14: safety documentation.
The focus of the LC14 aspects of the inspection was the testing arrangements and records to confirm that there is adequate evidence to demonstrate that the DEL chillers meet the claims placed on them by the HPC safety case.
Sampling ahead of the inspection found adequate traceability from the safety case to the high-level safety functional requirements placed on the chiller.
The Friotherm test bed is a capable facility that is able to test the chillers under load, and sampling of the completed test procedures identified the demonstration of key requirements such as cooling capacity. Sampling also found the C&I requirements are adequately managed via a traceability matrix.
I identified a shortfall in that the chiller requirements are not currently being managed by a requirements traceability matrix (RTM). I consider an RTM, or other suitable documentation, is necessary in order for NNB to be confident that all of the requirements placed on Friotherm in the BSTC and contract datasheet have been met, and to provide traceability to where they are evidenced (design, analysis or test evidence).
I consider this is important to demonstrate that the chillers meet the safety functional requirements placed on them by the safety case, to support compliance with LC14(1). Whilst I considered raising a regulatory issue to track the required improvements, I am content that NNB have already recognised the issue and will track this via open point DEL-036, which NNB informed me includes adding additional detail to the SAN to capture where chiller requirements are demonstrated.I judge that an inspection rating of GREEN (no formal action) is appropriate for LC12: duly authorised and other suitably qualified and experienced persons
The focus of the LC12 aspects of the inspection was to confirm that there are adequate arrangements to ensure personnel involved in the manufacture and testing of the DEL chillers are suitably qualified and experienced to carry out such tasks.
Based on sampling of the Friotherm competency records I am content there are adequate processes in place to ensure personnel are suitably qualified and experienced persons (SQEP).
I judge that an inspection rating of GREEN (no formal action) is appropriate for LC19: construction or installation of new plant.
The focus of the LC19 aspects of the inspection was to confirm that NNB have effective oversight of Friotherm’s manufacturing and test activities.
Based on the surveillance activities described by NNB, quality improvements implemented, and sampling of non conformance records, I am content that NNB have adequate arrangements in place for surveillance of the DEL chiller contract.