Safety

The Hydrogen Incidents and Accidents Database (HIAD) is an international open communication platform collecting systematic data on hydrogen-related undesired events (incidents or accidents). It was initially developed in the frame of the project HySafe an EC co-funded NoE of the 6th Frame Work Programme by the Joint Research Centre of the European Commission (EC-JRC) and populated by many HySafe partners. After the end of the project the database has been maintained and populated by JRC with publicly available events.<br/>Starting from June 2016 JRC has been developing a new version of the database (HIAD 2.01). With the support of the Fuel Cells and Hydrogen 2 Joint Undertaking (FCH 2 JU) the structure of the database and the web-interface have been redefined and simplified resulting in a streamlined user interface compared to the previous version of HIAD. The new version is mainly focused to facilitate the sharing of lessons learnt and other relevant information related to hydrogen technology; the database is publicly released and the events are anonymized. The database currently contains over 250 events. It aims to contribute to improve the safety awareness fostering the users to benefit from the experiences of others as well as to share information from their own experiences.<br/>The FCH 2 JU launched the European Hydrogen Safety Panel (EHSP2) initiative in 2017. The mission of the EHSP is to assist the FCH 2 JU at both programme and project level in assuring that hydrogen safety is adequately managed and to promote and disseminate hydrogen safety culture within and outside of the FCH 2 JU programme. Composed of a multidisciplinary pool of experts – 16 experts in 2018 - the EHSP is grouped in small ad-hoc working groups (task forces) according to the tasks to be performed and the expertise required. In 2018 Task Force 3 (TF3) of the ESHP has encompassed the analysis of safety data and events contained in HIAD 2.0 operated by JRC and supported by the FCH 2 JU. In close collaboration with JRC the EHSP members have systematically reviewed more than 250 events.<br/>This report summarizes the lessons learnt stemmed from this assessment. The report is self-explanatory and hence includes brief introduction about HIAD 2.0 the assessment carried out by the EHSP and the results stemmed from the joint assessment to enable new readers without prior knowledge of HIAD 2.0 to understand the rationale of the overall exercise and the lessons learnt from this effort. Some materials have also been lifted from the joint paper between JRC and EHSP which will also be presented at the International Conference on Hydrogen Safety (ICHS 2019) to provide some general and specific information about HIAD 2.0.

Hydrogen is an explosive gas which could create extremely hazardous conditions when released into an enclosure. Full-scale experiments of hydrogen release and dispersion in the confined space were conducted. The experiments were performed for hydrogen release outflow of 63 × 10−3 m3/s through a single nozzle and multi-point release way optionally. It was found that the hydrogen dispersion in an enclosure strongly depends on the gas release way. Significantly higher hydrogen stratification is observed in a single nozzle release than in the case of the multi-point release when the gas concentration becomes more uniform in the entire enclosure volume. The experimental results were confirmed on the basis of Froud number analysis. The CFD simulations realized with the FDS code by NIST allowed visualization of the experimental hydrogen dispersion phenomenon and confirmed that the varied distribution of hydrogen did not affect the effectiveness of the accidental mechanical ventilation system applied in the tested room.

Autoignition risk in initially non-premixed flowing systems such as premixing ducts must be assessed to help the development of low-NOx systems and hydrogen combustors. Such situations may involve randomly fluctuating inlet conditions that are challenging to model in conventional mixture-fraction-based approaches. A Computational Fluid Dynamics (CFD)-based surrogate modelling strategy is presented here for fast and accurate predictions of the stochastic autoignition behaviour of a hydrogen flow in a hot air turbulent co-flow. The variability of three input parameters i.e. inlet fuel and air temperatures and average wall temperature is first sampled via a space-filling design. For each sampled set of conditions the CFD modelling of the flame is performed via the Incompletely Stirred Reactor Network (ISRN) approach which solves the reacting flow governing equations in post-processing on top of a Large Eddy Simulation (LES) of the inert hydrogen plume. An accurate surrogate model namely a Gaussian Process is then trained on the ISRN simulations of the burner and the final quantification of the variability of autoignition locations is achieved by querying the surrogate model via Monte Carlo sampling of the random input quantities. The results are in agreement with the observed statistics of the autoignition locations. The methodology adopted in this work can be used effectively to quantify the impact of fluctuations and assist the design of practical combustion systems. © 2022 The Authors. Published by Elsevier Inc. on behalf of The Combustion Institute.

This review examines the central role of hydrogen particularly green hydrogen from renewable sources in the global search for energy solutions that are sustainable and safe by design. Using the hydrogen square safety measures across the hydrogen value chain—production storage transport and utilisation—are discussed thereby highlighting the need for a balanced approach to ensure a sustainable and efficient hydrogen economy. The review also underlines the challenges in safety assessments points to past incidents and argues for a comprehensive risk assessment that uses empirical modelling simulation-based computational fluid dynamics (CFDs) for hydrogen dispersion and quantitative risk assessments. It also highlights the activities carried out by our research group SaRAH (Safety Risk Analysis and Hydrogen) relative to a more rigorous risk assessment of hydrogenrelated systems through the use of a combined approach of CFD simulations and the appropriate risk assessment tools. Our research activities are currently focused on underground hydrogen storage and hydrogen transport as hythane.

Metal oxide semiconductor (MOS) is promising in developing hydrogen detectors. However typical MOS materials usually work between 200-500°C which not only restricts their application in flammable and explosive gases detection but also weakens sensor stability and causes high power consumption. This paper studies the sensing properties of UV enhanced Pd-SnO2 nano-spherical composites at 80-360 ℃. In the experiment Pd of different molar ratios (0.5 2.5 5.0 10.0) was doped into uniform spherical SnO2 nanoparticles by a hydrothermal synthesis method. A xenon lamp with a filter was used as the ultraviolet excitation light source to examine the response of the spherical Pd- SnO2 nanocomposite to 50-1000 ppm H2 gas. The influence of different intensities of ultraviolet light on the gas-sensing properties of composite materials compared with dark condition was analyzed. The experiments show that the conductivity of the composites can be greatly stabilized and the thermal excitation temperature can be reduced to 180 ℃ under the effect of UV enhancement. A rapid response (4.4/ 17.4 s) to 200 ppm of H2 at 330 °C can be achieved by the Pd-SnO2 nanocomposites with UV assistance. The mechanism may be attributed to light motivated electron-hole pairs due to built-in electric fields under UV light illumination which can be captured by target gases and lead to UV controlled gas sensing performance. Catalytic active sites of hydrogen are provided on the surface of the mixed material by Pd. The results in this study can be helpful in reducing the response temperature of MOS materials and improving the performance of hydrogen detectors."

This report is a detailed discussion related to safety shoes heat and flame personal protective equipment (PPE) and breathing apparatus (respiratory protective equipment RPE) required for working with natural gas (NG) and hydrogen (H2). This work was undertaken by HSE Science Division (SD) as part of Phase 2a of the H21 project. This report should be read alongside all the other relevant reports generated as part of this project. Recommendations made in this report are focused solely on the provision and use of PPE and should not be considered independently of recommendations made in the other relevant reports.<br/>Understanding the similarities and difference of PPE required for NG and H2 enables a deeper understanding of how the transition from NG to 100% H2 might change the way the gas distribution network is operated and managed.

The European Marine Energy Centre’s (EMEC) ITEG project (Integrating Tidal Energy into the European Grid) funded by Interreg NWE combines a tidal energy and hydrogen production solution to address grid constraints on the island of Eday in Orkney. The project will install a 0.5MW electrolyser at EMEC’s existing hydrogen production plant. EMEC and Risktec collaboratively applied best practice risk assessment and management techniques to assess and manage hydrogen safety. Hazard identification (HAZID) workshops were conducted collaboratively with design engineers through which a comprehensive hazard register was developed. Risktec applied bowtie analysis to each major accident hazard identified from the hazard register via virtual workshop with design engineers. The bowties promoted a structured review of each hazard’s threat and consequence identifying and reviewing the controls in place against good practice standards. The process revealed some recommendations for further improvement and risk reduction exemplifying a systematic management of risks associated with hydrogen hazards to as low as reasonably practicable (ALARP). Hardware based barriers preventing or mitigating loss of control of these hazards were logged as safety critical elements (SCE) and procedural barriers as safety critical activities (SCA). To ensure that all SCEs and SCAs identified through the risk assessment process are managed throughout the facility’s operational lifetime a safety management system is created giving assurance of overall safety management system continued effectiveness. The process enables the demonstration that design risks are managed to ALARP during design and throughout operational lifetime. More importantly enabling ITEG to progress to construction and operation in 2021.

Three different types of symmetrical tilt grain boundaries Ȉ3 Ȉ11 and Ȉ27 were constructed to study the dislocation behavior under the indentation on bi-crystal nickel. After hydrogen charging the number of hydrogen atoms in the Ȉ3 sample is the smallest and gradually increases in Ȉ11 and Ȉ27 samples. The force-displacement curve of indentation shows that the deformation resistance of the Ȉ3 sample is significantly higher than that of Ȉ11 and Ȉ27 samples. With the presence of grain boundaries the deformation resistance of Ȉ11 and Ȉ27 samples is significantly improved while the deformation resistance of the Ȉ3 VDPSOH is weakened. The indentation depth during the formation of dislocations in single  crystals  is  significantly  greater  than  that  of  bi-crystals.  Grain   boundaries  slow  down  the dislocation  propagation speed.  Compared  with  the  bi-crystals   without  hydrogen  the  presence  of hydrogen reduces the deformation resistance and accelerates the dislocation propagation.

Common root causes are often to be found in many if not most process safety incidents. Whilst largescale events are relatively rare such events can have devastating consequences. The subsequent investigations often uncover that the risks are rarely visible the direct causes are often hidden and that a ‘normalization of deviation’ is a common human characteristic. Process Safety Management (PSM) builds on the valuable lessons learned from past incidents to help prevent future recurrences. An understanding of how PSM originated and has evolved as a discipline over the past 200 years can be instructive when considering the safety implications of emerging technologies. An example is hydrogen production where risks must be effectively identified mitigated and addressed to provide safe production transportation storage and use .

Passive  Autocatalytic  Recombiners  (PAR)  is  one  of  the  important  technical  mitigation   means  for hydrogen    combustion    in    the    NPP    containments    under    accident     conditions.    For    the PWR/VVER/CANDU units the PARs execute functions important for safety - reduce the local hydrogen concentration  to  an  acceptable  level  and  provide  the   homogenization  of  gas  composition  and  of temperature  fields  in  the  containment.   Certification  and  licensing  of  PAR  technology  have  been accepted for the different NPP types and in the different countries on the case-by-case basement. But a comprehensive and generally accepted terminology and procedures for PAR characterization and its performance and safety rating are still absent. As a next step in PAR's technology improvement and maturity it would be logical a development of their unified technical standardization and certification. Report is aimed to - 2) justify need in standardization of the PARs in the nuclear industry and in the hydrogen energy applications 2) define a minimal set of the notions which can be used for quantitative characterization of the of PARs throughout its life-cycle 3) formulate a systemic (generic state-machine or automata) model of PAR's states under the normal and accident conditions. After verification and validation  of  proposed  PAR  systemic  model  it  can  be  used as  one  of  ints  for  the development of an international standard for PAR performance and safety.