Interesting that it is "withdrawn". This might be because Boeing did not want to pay the maintenance fees-- in the USA at least, these become quite costly for a large entity in the last years before expiration-- possibly combined with some concern or conclusion that it was "impossible" . In any case, if the patent represented any useful claims, then "expiration" now places the invention and its claims in the public domain.
I think the Boeing patent and perhaps other old patents provide an excellent free resource and starting point for inventors and replicators interested in pushing forward the basic sciences and technologies underlying CF / LENR.
Is it time for an online database summarizing the claims, inventors and general technology of such patents worldwide?