EPW when possible and to increase the deceleration capability level of the internal components. No changes in the parent weapon yield are allowed. The study is allowed to address potential changes to internal components, as long as the changes do not require any nuclear certification tests. Owing to budget constraints the study is now limited to the robust nuclear earth penetrator (RNEP) being studied by the LLNL/SNLL team. At this time there is no decision on when or if the LANL/SNLA team will restart its study.

Following are general guidelines from the DOD for the RNEP under study by the LLNL/SNLL team:9

  • The RNEP weapon is required to be able to do the following:

    • Survive penetration and not rebound from the target;

    • Reach a certain depth in a specified geology (the “threshold”);

    • Preserve or improve original weapon functionality; and

    • Preserve or improve original weapon safety, security, and reliability.

  • Regarding the compatibility of the RNEP with delivery aircraft:

    • The maximum weight, length, and diameter of the EPW case are to be determined by delivery aircraft requirements.

  • Modifications to the Arming, Fusing, and Firing (AF&F) system are allowed.

    • The AF&F capability level is to be determined by structural testing.

  • Modification of the nuclear system is allowed provided no nuclear certification testing is required.

The properties of the LLNL/SNLL RNEP are as follows:

  • Mass, including tail kit—1,379 kg,

  • Diameter—0.53 m, and

  • Penetrator length (may be extended by tail kit)—2.54 m.

Following are guidelines from the DOD regarding the RNEP guidance system:

  • RNEP is to be a guided and controlled weapon system. Its guidance system will do the following:

    • Allow for precise targeting,

    • Allow for optimization of angle of attack and incidence control, and

    • Minimize the stresses on the EPW system.

  • RNEP system capability will be determined by experimentation, test, and analysis.

    • The RNEP survivability level is set by the structural limit of the nuclear system and the arming, fusing, and firing system.



F.C. Alexander. 1967. History of Gun Type Bombs and Warheads Mark 8, 10, 11 (U), SC-M-67-658, Sandia National Laboratories Library, Albuquerque, N.Mex., May (Classified).


W.N. Caudle and A.Y. Pope. 1962. Project Trump: Progress Report No. I, SCTM 56-62 (71), Sandia Program for Earth Penetrating Systems, Sandia Corporation, Albuquerque, N.Mex., April.


W.J. Patterson and R.S. Baty. 2003. “Comparison of Two Empirical Equations with Large Scale Penetrator Tests into In Situ Rock Targets,” 11th International Symposium on Interaction of the Effects of Munitions with Structures, Mannheim, Federal Republic of Germany, May 5-9.

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