The RACER was developed in 1953 at Los Alamos , was DT gas-boosted and used a TOM initiator for internal initiation . The boosting capsule was made of steel and was internally lined with copper , a standardisation derived from the '' Booster Ball '' tested in the Item test . Inside the capsule , the TOM initiator was nested with a caltrop-like steel mounting . This method of assembly of the TOM initiator was known as '' sealed initiator '' , doing away with the mounting bracket employed in earlier pure-fission designs . Several RACER cores were proof-fired during Upshot – Knothole with mock-up secondary stages as shots Nancy ( Mark 14 ) with DT gas boosting , Badger ( Mark 16 ) with deuterium-only gas boosting , and a redesigned ( RACER IV ) core as shot Simon ( Mark 17/24 ) with DT gas boosting . In its finalised , RACER IV configuration , two kilograms of HEU were added to the initial ( RACER ) composite core design . According to Chuck Hansen , during the Upshot-Knothole tests RACER exhibited inconsistent yield , varying from 23 kilotons in the Badger and 24 kilotons in the Nancy shot , to 43 kilotons in the Simon shot ( as the revised RACER IV version ) ; the yields lay outside the predicted range of 35-40 kilotons . Concomitant to stringent yield predictability and reproducibility requirements , the design 's bizarre yields meant that as a primary , RACER did not furnished the '' proper '' quantity and strength of x-rays and neutrons to implode and initiate respectively the secondary stage . Both x-ray and neutron fluxes were products of the fission process and the degree of fission in the RACER cores varied unpredictably as shown by the yield variability . The unpredictable neutron flux had a catastrophic impact to the TX-22 program , as the MORGENSTERN prototype fizzled and its sister project RAMROD was canceled due to the poor performance of RACER IV
Item test
Greenhouse Item
RACER IV