Adjective : unexpendable resources vital to our security. ,an unexpendable source of energy. ,The principal of the trust fund is unexpendable.    From Dictionary.com. 

There was no good reason why the Traveler should send a boat and three highly unexpendable humans down to look at its lifelessness.    From Wordnik.com.  [Explorations]

Whether it be a primate or a sociopath, the real question is this: how did we let one company become so crucially unexpendable that our economy teeters on its very existence?.    From Wordnik.com.  [keg of populist ire on tap] Reference

But nature sustained by unexpendable forces must abide.    From Wordnik.com.  [Recreations in Astronomy With Directions for Practical Experiments and Telescopic Work] Reference

Nature filled with unexpendable forces continues in form.    From Wordnik.com.  [Recreations in Astronomy With Directions for Practical Experiments and Telescopic Work] Reference

Sylvester Stallone pursued by Brazilian company for unexpendable debts star could face a £1. 36m lawsuit brought by O2, his partners on The Expendables production, his latest action outing Sylvester.    From Wordnik.com.  [WN.com - Articles related to Meryl Streep playing Tina Fey's mom in comedy] Reference

No one´s unexpendable.    From Wordnik.com.  [Filmstalker Review: Superman Returns] Reference