biostudies-literatureUnknown334(12)Joyce MJMeasurements of refractory and volatile components in soils from Northern England confirm ²⁴⁴Pu/²³⁹Pu consistent with the global average but refractory ²⁴⁰Pu/²³⁹Pu significantly higher but consistent with Chernobyl fallout, i.e., 0.390 ± 0.006. Refractory formation suggests temperatures > 3000°C, consistent with atmospheric injection by nuclear-driven explosions rather than  by steam or hydrogen. Volatile ²⁴⁰Pu/²³⁹Pu is consistent with the global average, 0.181 ± 0.002, and hence lower-temperature formation in the chemical explosions and subsequent fire. This hypothesis is supported by ²³⁹Pu fission and capture cross-section enhancement due to the S-wave resonance at ~ 0.3 eV. A further calibration with a ²⁴⁰Pu standard is recommended to substantiate these observations.<h4>Supplementary information</h4>The online version contains supplementary material available at 10.1007/s10967-025-10541-0.Journal of radioanalytical and nuclear chemistry9287-9299https://www.ebi.ac.uk/biostudies/studies/S-EPMC12827445biostudies-literaturePlutonium signatures in refractory fallout support a Chernobyl nuclear jet hypothesis.PMC12827445Gautschi PJoyce MJCollins-Price PLivens FWilbraham RWarwick PGaca PSemple KTBoxall CMadina AChristl MfalsePlutonium signatures in refractory fallout support a Chernobyl nuclear jet hypothesis.Measurements of refractory and volatile components in soils from Northern England confirm ²⁴⁴Pu/²³⁹Pu consistent with the global average but refractory ²⁴⁰Pu/²³⁹Pu significantly higher but consistent with Chernobyl fallout, i.e., 0.390 ± 0.006. Refractory formation suggests temperatures > 3000°C, consistent with atmospheric injection by nuclear-driven explosions rather than  by steam or hydrogen. Volatile ²⁴⁰Pu/²³⁹Pu is consistent with the global average, 0.181 ± 0.002, and hence lower-temperature formation in the chemical explosions and subsequent fire. This hypothesis is supported by ²³⁹Pu fission and capture cross-section enhancement due to the S-wave resonance at ~ 0.3 eV. A further calibration with a ²⁴⁰Pu standard is recommended to substantiate these observations.<h4>Supplementary information</h4>The online version contains supplementary material available at 10.1007/s10967-025-10541-0.2025-01-01T00:00:00Z20252026-06-06T22:29:08.238Z2026-06-06T03:10:38.966ZS-EPMC128274454158625010.1007/s10967-025-10541-0