( ( Because ( it ( has ( isotopes ( with ( ( very long ) half-lives ) ) ) ) ) ) ( , ( it ( ( is ( of ( ( particular concern ) ( in ( ( the context ) ( of ( designing ( ( confinement facilities ) ( that ( can ( last ( for ( thousands ( of years ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Because) (S (NP (PRP it)) (VP (VBZ has) (NP (NP (NNS isotopes)) (PP (IN with) (NP (ADJP (RB very) (JJ long)) (NNS half-lives))))))) (, ,) (NP (PRP it)) (VP (VBZ is) (PP (IN of) (NP (NP (JJ particular) (NN concern)) (PP (IN in) (NP (NP (DT the) (NN context)) (PP (IN of) (S (VP (VBG designing) (NP (NP (NN confinement) (NNS facilities)) (SBAR (WHNP (WDT that)) (S (VP (MD can) (VP (VB last) (PP (IN for) (NP (NP (NNS thousands)) (PP (IN of) (NP (NNS years)))))))))))))))))) (. .)))
Because it has isotopes with very long half-lives, it is of particular concern in the context of designing confinement facilities that can last for thousands of years.
(ROOT (S (NP (DT The) (JJ long-lived) (NNS isotopes)) (VP (VBP require) (NP (NP (NNS thousands)) (PP (IN of) (NP (NP (NNS years)) (PP (TO to) (NP (NN decay)))))) (PP (TO to) (NP (NP (DT a) (JJ safe) (NN level)) (PP (IN in) (NP (DT a) (JJ nuclear) (NN reactor)))))) (. .)))