E E' CISE EXERCISE PAGE 1 OP 3 - AGGREGATE ASSESMENT--ONE HOUR--OP THREAT MESSAGE AND SKETCH With a high degree of confidence we conclude that the threat is for real The drawing accoMpanying the threat Message illustrates a geoMetry which as far as experiNental MeasureMents done- i Montrev are conc•rnect is essentially identical to the Montrev device We believe the Montrev device o be capable of nuclear yield Insufficient data is avai l yield cl sely it coulq__ i 11 t he-1 e n s_Qf b ilQ_t_gns_ran9e• I I l b 1 l i ·rcCHNICAL CREDIBILITY By F KloverstroM w I Mudd SUMMARY CONCLUSION t I The drawing accoMpanying threat Message Matches the evidence now in hand in Montrev quite closely ExperiMental evidence in Motrev also indicates t tiat plutoniu - 1 is containe in the box We are - 1oderately confitient that the device is capable of prod cing nuclear yield It is likely that if a device appears in the Midwest _i is a duplicate of that in Montrev The potential· boostecl yield of this dev ce is dependent on the a - 1OL111t' of p lt1toniL _ - _1 __ antl bJ l s · an d a l Ei esent bl 1 r --· 1 ib 3 These yields are first estil'1ates onl9 -rroc alculations· nd i catecl ctiP1ensions have b en done they are beginning The ••1 -1e' tH11 e t neL1tron er1ission of the device should help in search planning if' • such is necessary in the Midwest i i t'h the 1 b 3 I ' _ · a'tiona l b 3 8EHAVIORIAL CREDIBILITY By M Miron SUMMARY CONCLUSIONS ib 1 j - The discrepancies fro such presuMpt1on are sufficient ry ··- eJCPII' W laait urn m I V rnno'l