Helium Loss Research Articles

Assessing the Helium Potential of Variscan Batholiths: Insight From Corsica Island

AbstractMost of the current helium (He) reserves originate from fortuitous discoveries, mainly made during oil and gas exploration in sedimentary basins. As helium generation depends on U and Th α‐decay, old geological provinces gather key ingredients for high He accumulation. However, numerous He‐rich springs have also been documented in much younger rocks, such as Variscan granites (320–250 Ma). These latter discoveries question the current exploration guidelines and require revisiting some of the longstanding paradigms. Here, is investigated He migration along a major fault rooted in the Corso‐Sardinian batholith (France). Two thermal springs, Caldanelle and Guagno‐Les‐Bains, show significant outgassing activities of crustal sourced He with concentrations up to 1.45 vol% and flow rates of 110 m3 STP 4He/year. Besides He, the gas phase is dominated by N2 (≈98 vol%) and minor CH4. Based on a survey employing multidisciplinary methodologies, it is revealed that (a) Variscan rocks represent efficient 4He source rocks, (b) the main source of He comes from the underlying Eo‐Variscan basement, (c) A deeply rooted fault and dense fractures networks drain the He, (d) the helium loss is limited, (e) faults and fractures may act as partial traps, and finally (f) the presence of an efficient trap could promote a He‐rich reservoir with high flux but low reserves. In that sense, young post‐orogenic granites represent promising helium plays. The geological context in which Caldanelle and Guagno‐Les‐Bains are embedded is ubiquitous in European Variscan batholiths. This case study is therefore intended to serve as a guide for helium exploration and to provide insights into helium behavior within a Variscan geological context.

Degassing of CO2 triggers large-scale loss of helium from magma oceans

The moon-forming impact caused widespread melting and vaporization of the proto-Earth, leading to the formation of a protolunar disk1,2. Volatile elements trapped in the inner parts of the disk condensed together with heavier elements into a global magma ocean3,4. By subsequent cooling and degassing, volatiles contributed to the formation of the Earth’s secondary atmosphere5. The thermodynamic conditions at the magma ocean-atmosphere interface profoundly impacted the degree of degassing that occurred. Today, our understanding of these conditions remains unclear. Here, we simulate the degassing of carbon and helium from a magma ocean with a bulk silicate Earth composition6 at presumed typical conditions for the early Earth5,7. We employ first-principles molecular dynamics calculations. We find that volatile loss is determined by pressure, temperature, and melt composition. Carbon and helium devolatilize more easily when both elements are present in the melt, leading to pronounced loss from the magma ocean. Our findings suggest that the early Earth atmosphere was carbon-rich, with a high fraction of helium and other noble gases, and thicker and hotter than previously thought. We evaluate the implications for Earth’s composition and thermal evolution, as well as other planets that may undergo similar processes with different chemistries.

Optimal design of coolant jacket for cryogen transfer pipelines

AbstractCryogenic liquids such as liquid oxygen and liquid hydrogen are extensively used in many processes and manufacturing industries. In these industries, transferring cryogens via pipelines is a routine phenomenon. As the boiling points and latent heat of cryogens are low, excessive vaporization of these cryogens is innate. Therefore, ensuring that the cryogen reaches the utility in its liquid form is challenging. In the case of liquid hydrogen and liquid helium, the pipelines are jacketed with a high boiling cryogen like nitrogen. The idea is to dump most of the heat into cheap nitrogen to limit the loss of precious hydrogen or helium. From a heat inleak point, maximizing the amount of nitrogen in the jacket is advantageous by choosing large cross‐sectional areas. Also, larger flow cross sections would lower pressure drops and, therefore, lower pumping costs. However, such a choice would add to the mass of the pipeline. An increase in the mass of the pipeline increases the need for better structural support of the pipeline assembly. Therefore, the design of cryogen jackets for limiting heat inleak is a multi‐objective optimization problem. In this work, we model the heat leak into the hydrogen via the nitrogen jacket and the pressure drop of liquid nitrogen, and we find the mass of the pipeline assembly. Then, we optimize the design of nitrogen jackets fitted over hydrogen pipelines. We employ the evolutionary optimization technique, genetic algorithm (GA), to perform this optimization.cryogen; genetic algorithm; heat inleak; liquid hydrogen; optimization.

Conservation of Helium while Maintaining High System Purity

Recent helium shortages and helium price increases have lead to an increased emphasis being placed on conserving helium. The need to conserve helium must be balanced with need to maintain the high levels of purity necessary to prevent operational problems caused by contamination. Helium losses and contamination control are especially important for test stands that have cryogenic distribution systems operating continuously with frequent changeover of cryogenic temperature components that are being tested. This paper describes a mathematical model to estimate the quantity of helium lost and the purity of the helium after the pump and backfill procedure is complete. The process to determine the optimal time during pump down to cut off pumping and start backfilling is described. There is a tradeoff between trying to achieve the lowest possible pressure during pumping and the quantity of air leaking into the volume while pumping is occurring. An additional benefit of careful selection of pump and backfill parameters in conjunction with real-time pressure monitoring can reduce the labor and time required to complete a successful pump and backfill procedure. This paper is intended to be a tool for engineers to review their pump and backfill procedures and measured data to optimize helium losses, system purity, and labor required.

A radius valley between migrated steam worlds and evaporated rocky cores

AbstractThe radius valley (or gap) in the observed distribution of exoplanet radii, which separates smaller super-Earths from larger sub-Neptunes, is a key feature that theoretical models must explain. Conventionally, it is interpreted as the result of the loss of primordial hydrogen and helium (H/He) envelopes atop rocky cores. However, planet formation models predict that water-rich planets migrate from cold regions outside the snowline towards the star. Assuming water to be in the form of solid ice in their interior, many of these planets would be located in the radius gap contradicting observations. Here we use an advanced coupled formation and evolution model that describes the planets’ growth and evolution starting from solid, moon-sized bodies in the protoplanetary disk to mature Gyr-old planetary systems. Employing new equations of state and interior structure models to treat water as vapour mixed with H/He, we naturally reproduce the valley at the observed location. The model results demonstrate that the observed radius valley can be interpreted as the separation of less massive, rocky super-Earths formed in situ from more massive, ex situ, water-rich sub-Neptunes. Furthermore, the occurrence drop at larger radii, the so-called radius cliff, is matched by planets with water-dominated envelopes. Our statistical approach shows that the synthetic distribution of radii quantitatively agrees with observations for close-in planets, but only if low-mass planets initially containing H/He lose their atmosphere due to photoevaporation, which populates the super-Earth peak with evaporated rocky cores. Therefore, we provide a hybrid theoretical explanation of the radius gap and cliff caused by both planet formation (orbital migration) as well as evolution (atmospheric escape).

Design and Fabrication of a Test Rig to Determine Helium Permeability through Fabrics

The fabric of a Lighter-Than-Air (LTA) system experiences permeation of Helium over a period of time. Due to the small size of the molecules of Helium, it permeates through the intermolecular spaces of the fabric. This leakage increases with time due to the degradation of the fabric. LTA systems need to be deployed for long durations. The loss of Helium due to permeation reduces the relative lift of the LTA system. The unknown permeation rates thus lead to uncertainties in the deployment time of the system. This paper describes the design and fabrication of a test rig to determine the permeability of Helium through different fabrics. This method involves a permeation cell divided into upper and lower chambers arranged to hold a specimen fabric between them, with the provision of a continuous supply of Helium in the lower chamber. A Phoenix L300i Helium Leak Detector (HLD) is connected to the upper chamber to detect Helium and measure its concentration. The further objective of this research is to study the variation of helium permeability through the fabrics at constant temperature and input pressure with time.

Testing a new combined (U,Th)–He and U/Th dating approach on Plio-Pleistocene calcite speleothems

The geochronology of cave deposits in the Cradle of Humankind UNESCO World Heritage Site in South Africa provides a timeframe essential for the interpretation of its fossils. The uranium-lead (U–Pb) and uranium-thorium disequilibrium (U/Th) dating of speleothems, mostly flowstones that underlie and blanket the fossil-bearing sediments, have been effective in this sense, but U–Pb is limited by the requirement of ∼1 ppm U concentrations and low common Pb contents, and U/Th has a c. 500 ka limit of applicability. Here we report age results for calcite-aragonite speleothems obtained using a new combined uranium-thorium-helium ((U,Th)–He) and U/Th dating routine. We reproduced within analytical uncertainty, the published U–Pb or U/Th ages for (a) flowstone in three drill core samples in the range 2000–3000 ka, (b) a flowstone hand sample taken at surface with an age of 1800 ka, and (c) five underground flowstone samples in the range 100–800 ka. Calcite retentivity for He under cave conditions is thus demonstrated. In the few cases where helium loss was observed in speleothems, only some of the subsamples were affected, and to varying degrees, suggesting loss by lattice damage not related to diagenetic processes, rather than volume diffusion. In the 100 to 800 ka range, the combined U/Th disequilibrium and (U,Th)–He method also yielded reliable values for initial (230Th/238U) and (234U/238U) activity ratios. Importantly, most subsamples had high initial (230Th/238U) values, ranging from 1.0 to 19.7, although having low Th/U ratios. This is probably due to incorporation of Fe–Mn oxides-hydroxides dust, on which 230Th was previously adsorbed. Such samples are mostly not dateable by U/Th without the additional input from the He analysis. If not detected and corrected for, such high initial (230Th/238U) values can lead to inaccurate U/Th and U–Pb ages. Our study shows that the incorporation of He analysis in U/Th dating has broad potential application, with four methods for calculating the ages, in carbonates from different environments where U-Pb or U/Th dating would not work.

Severe accident analysis of the dual-functional lithium-lead test blanket module using ISAA-DFLL code

The international thermonuclear experimental reactor (ITER) project aims to build a tokamak fusion test reactor to verify the feasibility of fusion reactors. The test blanket module (TBM) is the key component of the international thermonuclear experimental reactor. The fusion design study team proposed the concept of the dual-functional lithium-lead test blanket module (DFLL-TBM). The integral severe accident analysis (ISAA) is a self-developed ISAA code that models the progression of severe accidents in nuclear power plants. A broad spectrum of severe accident phenomena including fission product release and transport behavior is modeled in ISAA. In this paper, a new version of ISAA, referred to as ISAA-DFLL is introduced for the application of DFLL-TBM test blanket module into the treatment of multi fluids and the modules of the new physical property and heat transfer. The modification is verified by comparing the steady-state temperature distribution of the DFLL-TBM first wall with the design parameters. Then accident analysis of In-vessel loss of helium coolant in first wall and TBM pipe is conducted by using the ISAA-DFLL code. By comparing the calculation results with the general safety requirements for TBM, it is concluded that the design of the DFLL-TBM system and the modifications of the current version are reasonable and accurate.

Light noble gas records and cosmic ray exposure histories of recent ordinary chondrite falls

AbstractWe measured noble gas concentrations and isotopic ratios (He, Ne, and Ar isotopes) in six recent ordinary chondrite falls: Mangui (L6), Viñales (L6), Ozerki (L6), Tamdakht (H5), Kheneg Ljouâd (LL5/6), and Katol (L6). Among them, the three L6 chondrites Mangui, Viñales, and Ozerki fell in only a few months' interval; their apparent similar petrographic and mineralogic characteristics might indicate source crater pairing. To test this hypothesis, we have investigated those meteorites for their cosmic ray exposure (CRE) histories, using the cosmogenic noble gases 3He, 21Ne, and 38Ar. We systematically (re)calculated the CRE ages as well as the gas retention ages of these meteorites. The CRE age of the Mangui is, based on noble gases, <1 Ma, which is unusually short for an L chondrite. Indeed, the range of exposure ages for L chondrites is generally distributed between ˜1 and ˜60 Ma, with major peaks occurring around ˜5, ˜30, and ˜40 Ma. In addition, the cosmogenic 3Hecos data of two Mangui duplicates are consistent with a remarkably high loss of helium by diffusion due to heating by solar radiation. Such a short parent body‐Earth transfer time (<1 Ma) can be explained by a delivery from an Earth‐crossing object. Regarding the other L6 chondrites, Viñales has a nominal CRE age of ˜9.4 Ma, whereas the Ozerki meteorite has a nominal CRE age of ˜1.2 Ma, which is consistent with Korochantseva et al. (2019). Based on their CRE ages as well as on their gas retention ages, it appears that none of these three recent L6 chondrite falls are source crater paired, and therefore, all three originate from different meteoroids. The nominal exposure ages of Tamdakht, Kheneg Ljouâd, and Katol are ˜3.2, ˜11, and ˜30 Ma, respectively, and are consistent with identified age peaks on the exposure age histogram of H, LL, and L chondrites, respectively. The nominal CRE age of Tamdakht is consistent with previous observations for H chondrites and implies that they are dominated by small impact events occurring in several parent bodies.

Helium retention, bubble superlattice formation and surface blistering in helium-irradiated tungsten

The microstructural evolution and helium retention in polycrystalline tungsten (W) implanted with 100 keV helium ions at different temperatures to a wide range of different fluences were studied. Rutherford backscattering spectrometry (RBS) shows that helium atoms were well retained in tungsten, and no loss of helium occurred before surface blistering/flaking occurred. Within certain windows of fluence and temperature, ordered bubble superlattices form. A minimum fluence and sufficiently high irradiation temperature are necessary to establish a bubble superlattice, but continued introduction eventually destroys the order via bubble linkage and crack nucleation occurring at the depth of peak helium deposition. Scanning electron microscopy showed that typical sizes of flakes were roughly the same, independent of helium fluence. With increasing fluence, the number of flakes increased, and often linked together, forming a massive peeled off region. Using RBS-measured helium retention and TEM-measured bubble density, we obtained an interfacial energy of 2.53±0.72 J/m2. There is no observation of bubble denuded zones at grain boundaries, suggesting that bubbles represent a stronger defect sink than grain boundaries or cracked grain boundaries.

Exposure Ages, Noble Gases and Nitrogen in the Ordinary Chondrite Karimati (L5)

Noble gas and nitrogen isotopic compositions of Karimati ordinary (L5) chondrite are presented. Aliquots of the meteorite were studied in two noble gas mass spectrometers. Its cosmic ray exposure (CRE) history, trapped noble gases and nitrogen isotopic systematic are examined. The compositions of Ne and Kr in this meteorite indicate presence of mixture of solar wind and Q trapped components. In addition to the primordial components, radiogenic 129Xe (from the decay of short-lived radioactive 129I) is observed in the two aliquots (129Xe/132Xe ranges between 1.054 and 1.311). The U/Th-4He and K-40Ar ages are discordant. U/Th-4He ages are younger than the K-40Ar ages, indicating loss of helium. The trapped N component is isotopically light analogous to Q gas/solar wind. The cosmic-ray exposure ages of the two aliquots are 16.1 ± 2.7 Ma and 16.6 ± 2.0 Ma based on the cosmogenic 21Nec and 38Arc concentrations.

CFD analysis of the natural circulation of helium in the DEMO cryostat during a leak accident

Abstract After the ingress of helium into the DEMO cryostat the natural convection of the leaked helium is established inside the cryostat, driven by the temperature difference between the cold magnets and warm structures (vacuum vessel and cryostat). The cryostat is a large thin-walled vacuum vessel whose thermal contraction is constrained by its supports to the bioshield. The design of these supports depends on the temperature distribution on the inner side of cryostat walls. The loss of liquid helium from the superconducting coils into the cryostat is studied at both normal and baking conditions of the vacuum vessel. The studied helium leak accident considers the temperature of the magnet coils preserved at 59 K to represent the most severe case. Assuming a quasi steady-state condition to establish the natural convection of helium in the DEMO cryostat, a CFD code was used to determine the temperatures and the heat transfer coefficient on the cryostat inner wall.

Underground storage facilities for helium concentrate in porous medium

The gas of many fields in Eastern Siberia (Chayandinskoye, Kovyktinskoye, Sobinskoye, Chikanskoye, etc.) has a complex component composition with a high helium content. In order to realize the advantage of a unique raw material base, it is necessary to put into practice solutions for the industrial implementation of technologies for the extraction of helium, storage and transportation. One of the directions for the solution of these problems is the creation of temporary underground storage of helium concentrate in a porous medium next to gas chemical plants. This will ensure supply flexibility and reduce helium losses. The global demand for helium is continuously increasing from year to year and in the long term, a favorable situation will emerge on the global helium market for Russia, a positive effect from which can be achieved, provided the benefits of the raw material base are realized. A positive effect means not only the monetary effect, but also takes into account the formation of prerequisites for the development of new spheres of influence: access to new trading platforms and sales markets, the development of high-tech industries, basic and applied sciences, etc. In order to realize the advantage of the raw material base, Russia needs in a fairly short period of time to put into practice the decisions on the industrial introduction of gas separation technologies and underground helium storage.

Constraining in situ cosmogenic nuclide paleo-production rates using sequential lava flows during a paleomagnetic field strength low

The geomagnetic field prevents a portion of incoming cosmic rays from reaching Earth’s atmosphere. During magnetic reversals and excursions, the field strength can decrease by up to 90% relative to the modern-day value. During such anomalies, cosmic ray bombardment to Earth’s atmosphere increases as evident from atmospheric 10Be anomalies recorded in sediment and ice cores. However, how the flux of cosmic rays to Earth’s surface varies during such geomagnetic anomalies is not well constrained. We measured fossil cosmogenic 3He in olivine from the tops of two pairs of 40Ar/39Ar age-dated Tahitian lava flows that erupted during the Matuyama-Brunhes reversal precursor event. We corrected these raw values for the diffusive loss of helium caused by heating from the overlying flow with a diffusion model using cooling rates and maximum temperature conditions based on field measurements of active lava flows from Kilauea, Hawaii. We assume the maximum temperature suggested by field measurements and thus present a limiting case for the highest diffusive loss corrections and thus the highest paleo-production rates. Based on paleomagnetic field strength reconstructions and scaling factor models, the upper limits of the corrected in situ3He paleo-production rates (100 ± 23, 144 ± 35 atoms g−1 a−1) are in agreement with those expected during the period of a geomagnetic field strength low when these flow tops were exposed. However, the more plausible contact temperatures (<700°C maximum temperature in diffusion model) are associated with diffusion corrected paleo-production rates lower than those predicted by scalar models. This potential underestimation is likely a function of changes in local non-dipole field components, atmospheric density and/or an overestimation of the dipole field strength reduction during the M-B precursor event.

A Low-Temperature Broadband NMR Probe for Multinuclear Cross-Polarization.

Dissolution dynamic nuclear polarization (D-DNP) probes are usually designed for one or at most two specific nuclei. Investigation of multiple nuclei usually requires manufacturing a number of costly probes. In addition, changing the probe is a time-consuming process since a system that works at low temperature (usually between 1.2 and 4.2 K) must be warmed up, thus increasing the risks of contamination. Here, an efficient apparatus is described for D-DNP designed not only for microwave-enhanced direct observation of a wide range of nuclei S such as 1 H, 13 C, 2 H, 23 Na, and 17 O, but also for cross-polarization (CP) from I=1 H to such S nuclei. Unlike most conventional designs, the tuning and matching circuits are partly immersed in superfluid helium at temperatures down to 1.2 K. Intense radio-frequency (RF) fields with amplitudes on the order of 50 kHz or better can be applied simultaneously to both nuclei I and S using RF amplifiers with powers on the order of 90 and 80 W, respectively, without significant losses of liquid helium. The system can operate at temperatures over a wide range between 1.2 and 300 K.

Mass Loss of Different Stellar Populations in Globular Clusters: The Case of M4

Abstract In a Globular Cluster (GC), the mass loss during the red giant branch (RGB) phase and the helium content are fundamental ingredients to constrain the horizontal-branch (HB) morphology. While many papers have been dedicated to the helium abundance in different stellar populations, small efforts have been made to disentangle the effects of mass loss and helium content. We exploit the nearby GC NGC 6121 (M4), which hosts two well-studied main stellar populations, to infer both helium and RGB mass loss. We combine multi-band Hubble Space Telescope photometry of RGB and main-sequence (MS) stars of M4 with synthetic spectra to constrain the relative helium content of its stellar populations. We find that the second-generation stars in M4 are enhanced in helium mass fraction by with respect to the remaining stars that have pristine helium content. We then infer the mass of the HB stars by searching for the best match between the observations and HB populations modeled assuming the helium abundance of each population estimated from the MS. By comparing the masses of stars along the HB, we constrain the mass loss of first- and second-generation stars in M4. We find that the mass lost by the helium-enriched population is ∼13% larger than the mass lost by the first-generation stars ( ). We discuss the possibility that this mass-loss difference depends on helium abundance, the different formation environment of the two generations, or a combination of both.

Single Grain (U-Th)/He Ages from EET14074, an Acapulcoite Meteorite

EET14074 is a member of the acapulcoite-lodranite family of meteorites and was discovered in Antarctica in 2014 by the Korean Polar Research Institute (KOPRI). Herein, we obtained (U-Th)/He ages from 20 phosphate aggregates in EET14074 to constrain the sample’s thermal history. The ages range between 116.8 Ma ± 145.7 Ma (1σ) and 4211.5 Ma ± 1089.1 Ma, with an average of 2530 ± 260 Ma (n=20). Excluding outlier ages with large uncertainties, the 13 most concentrated ages yielded a theoretical minimum age of 3000 ± 150 Ma. This age corresponds to a fraction helium loss (f) of ~31% assuming crystallization age of ~4.55 Ga. The uranium abundances in single aliquots are in the range of 1.52 - 289.93 fmol, with an average of 58.00 fmol (n = 20), whereas the thorium abundance ranges between 2.51 and 2337.06 fmol with an average of 1149.29 fmol (n = 20). To explain the observed He loss, thermal diffusion modeling was performed with an assumption that the He loss occurred during a recent passage of the meteorite in Earth’s atmosphere. For the most likely t-T condition of compressional heating in Earth’s atmosphere of this meteorite (T = ~430 ˚C, t = ~10 sec), a fractional loss of 29.3% was calculated when the diffusion domain radius (r) of 92.8 µm was assumed. This estimation is nearly indistinguishable from the observed fractional loss of 31.3%. Additionally, diffusion modeling for another set of data with a different size (r = 40.4 µm) yielded a very similar fractional loss. Therefore, the observed (U-Th)/He age distribution is likely derived from compressional heating during the passage of EET14074 in Earth’s atmosphere.

Noble gas, nitrogen composition and cosmic ray exposure history of two eucrites Vissannapeta, Piplia Kalan and one howardite Lohawat

We have carried out detailed noble gases and nitrogen isotopic study of two eucrites Vissannapeta, Piplia Kalan and one howardite Lohawat. Neon is mainly produced by Galactic Cosmic Ray (GCR) in all the three meteorites. The estimated cosmic ray exposure ages are 23.8 ± 6.1 Ma, 28.4 ± 8.1 Ma and 46.4 ± 17.3 Ma for Piplia Kalan, Vissannapeta and Lohawat, respectively. Light nitrogen composition is present in Vissannapeta and Lohawat, while heavy nitrogen composition is observed in Piplia Kalan. The nitrogen is distinctly trapped in the eucrites. Elemental ratios of the trapped noble gases such as argon, krypton and xenon together with nitrogen composition in eucrites indicate their distinct source region in Vesta. A younger potassium-argon age for the eucrites (3.71 ± 0.42 Ga for Vissannapeta and 3.60 ± 0.15 Ga for Piplia Kalan) than the solar system formation age, indicates partial loss of the radiogenic argon during the evolutionary stages of these meteorites plausibly due to impact metamorphic events. The radiogenic ages derived from the 4He are less than 1 Ma suggesting loss of helium from the eucrites.

N–C–Ar–He Isotopic Systematics of Quenched Tholeiitic Glasses from the Bouvet Triple Junction Area

The paper presents pioneering data on the isotopic composition and elemental ratios of nitrogen, carbon (carbon dioxide), helium, and argon in the fluid phase of quenched tholeiitic glasses from different segments of the Bouvet Triple Junction area (BTJ). The data reflect a complicated geodynamic and tectonic history of the area evolution and indicate that the variations in the elemental ratios of the volatile components of the fluid–gas phase were controlled by a number of various factors: elemental fractionation during melt degassing, mixing of gases from different sources, postmagmatic diffusion-controlled helium loss. The nitrogen–argon and noble gas isotope systematics suggest a significant contribution of the atmospheric component to the mantle source of fluids for the samples from the Spiess Ridge and the segment of the Southwest Indian Ridge (SWIR) and a smaller contribution for the Mid-Atlantic Ridge (MAR) samples. For the Spiess Ridge and SWIR, the most probable contaminating agent was water fluid with dissolved gases of atmospheric composition. This fluid may have been brought to the mantle with ancient crustal rocks involved in magma generation. These crustal rocks may represent small fragments of the Gondwana continent with which sedimentary organic matter could be brought into the magma source.

Helium induced microstructure damage, nano-scale grain formation and helium retention behaviour of ZrC

Transition-metal ultra-high temperature ceramics are promising materials for nuclear structural applications. However, an understanding of their response to high-temperature irradiation and helium is vastly limited. This paper presents a study of helium effects in zirconium carbide (ZrC) by performing room temperature 3 MeV 3He+ ion irradiations up to 5 × 1020 ions m−2 (∼1.8 at.% at peak) and high-temperature annealing (1273–1873 K), coupled with state-of-art characterization using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and nuclear reaction analysis (NRA). We reveal that ZrC is susceptible to irradiation damage in terms of helium bubble formation. After annealing at 1373 K, tiny bubbles (1–2 nm) formed aligned clusters which were highly over-pressurized, producing strain contrast in TEM. At 1773 K, significant bubble growth occurred. Additionally, at 1773 K, a combined TEM/SEM analysis revealed dramatic matrix damage due to helium-induced surface blistering. Underneath blister caps, the microstructure evolved into ultra-fine nano-scale grains similar to high burn-up structures observed in nuclear fuels, but consisting of numerous nano-cracks. We hypothesize that such structures are formed due to high gas pressure build-up and its subsequent release. This phenomenon initiated at the grain boundaries. Blister top surface consisted of inter-granular and trans-granular cracks. NRA depth profiling revealed that helium was present as double peaks with major portion lying at the end-of-the-range (EOR) and the rest as TEM invisible clusters in a shoulder extending to the surface. ZrC started releasing helium after 1373 K. Helium release increased significantly at higher temperatures, with majority helium loss occurring from EOR rather than from near-surface regions.