Upper bounds on 'cold fusion' in electrolytic cells

Experiments using three different calorimeter designs and high-efficiency neutron and γ -ray detection on a wide range of materials fail to sustain the recent claims of cold fusion made by Fleischmann et al.1 and Jones et al.2. Spurious effects which, undetected, could have led to claims of cold fusion, include noise from neutron counters, cosmic-ray background variations, calibration errors in simple calorimeters and variable electrolytic enrichment of tritium.