Alterations

ALT 193_1.1
– A modification to provide compatibility with the aircraft clip-in suspension system by adapting the Bisch and valve pullout connections to the clip-in supporting structure. The lanyard arrangement for removing safing pins in flight cannot be used with ALT 193. For this reason, ALT 197 must be performed at the same time or prior to completion of ALT 193^1.1
– Applicable to all Mods of the Mk15 & Mk39_1.2

ALT 197^1.1
– Provides additional safing by introducing Arm/Safe switch contacts between the Bisch generator output and the low-voltage thermal battery matches. In this ALT, the MC1288 Arm/Safe switch is installed in place of the MC772. in addition to the contacts in lines presently controlled by the MC772, MC1288 contacts in the Bisch line insure that the thermal battery will not be operated if the weapon is released in the safe condition. When this ALT is accomplished, it is considered that the system is adequately safe for alert flying without safing pins installed in the pullout rods._1.1
– Applicable to all Mods of the Mk15 & Mk39_1.2

ALT 335^3.1
– Carried out between October 1998 and September 2003. Installed a Trajectory Sensing Signal Generator (TSSG), a safety improvement that increases the nuclear safety of the bomb in certain normal and abnormal environments._3.1
– Büchel AB received initial training in May 1996._3.1
– Applicable to the Mk61_10.1

ALT 339^3.1
– Carried out between October 1998 and September 2003. Installed the MC4519 MCCS Encryption Translator Assembly (MET) in Mk61 Mod 3, 4, and 10 to provide weapons with cryptographic capability to implement end-to-end encryption in the Permissive Action Link (PAL) Code Management System (CMS). MC4519 MET coupled with the CMS enables recoding of nuclear weapons in a fully encrypted manner. MET capability improves the positive controls over use of the warhead. Regular monthly shipments started in June 1997. The first CMS became operational on Mk61s in Europe on November 30, 2001._3.1
– Applicable to the Mk61 Mods 3, 4, & 10_3.1

ALT 354^3.1
– Carried out between March 2001 and March 2002. Adjustment of fin cant angle to improve weapon spin rates when used in conjunction with existing spin motor._3.1
– Applicable to the Mk61 Mods 3, 4, and 10_3.1

ALT 369_2.1
– replaced Limited Life Components (LLC)_2.1
– Applicable to the Mk80

ALT 370_6.1
– Mk88 SS-21 Project_6.1
– Replaced the arming, fuzing, and firing components_11.1
– Refreshes Conventional High Explosives (CHE)_9.1

ALT 370_4.1
– Replace electronic detonation hardware and replace conventional high explosives._4.1
– Applicable to the Mk88._4.1

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ALT 916_5.1
– A reversible ALT that removes the boosting-gas reservoir_5.1 from “inactive reserve” bombs. The ALT is performed by DOD teams at DOD locations_7.2
– The main and pulse_7.3 thermal batteries of the Mk53 are typically removed during this ALT as well_7.1
– Applicable to the Mk53_5.1

ALT 937_9.1
– Removes the gas reservoir and installs a shipping plug_9.1
– Applicable to the Mk80_9.1

ALT 940_6.1
– Gas transfer system (GTS) project to support Mk88 First Production Units (FPU)_6.1

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References

1. Mason & Hanger-Silas Mason Co., Inc. (1965). Broken Arrow Examination; Mason & Hanger-Silas Mason Co., Inc. Clarksville Facility (MH-SM-CF-PPR-BAE-65702; p. 417). https://www.governmentattic.org/40docs/NNSApost1980BrokenArrow_2021.pdf
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   2. p.80 (PDF Page)
2. Padilla, Michael. (2017, November 10). Sandia Supports First Production Unit of W80-1 Alt 369. Lab News, 69(22), 8. https://www.sandia.gov/news/publications/labnews/_assets/documents/issues/2017/labnews11-10-17.pdf
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3. Kristensen, H. M. (2005). US Nuclear Weapons in Europe: A Review of Post-Cold War Policy, Force Levels, and War Planning. National Resources Defense Council. https://www.nukestrat.com/pubs/EuroBombs.pdf
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4. Leone, D. (2019, May 10). Balky Capacitors Could Delay Two NNSA Nuke Refurb Programs. Nuclear Security & Deterrence Monitor, 1. https://www.exchangemonitor.com/balky-capacitors-delay-two-nnsa-nuke-refurb-programs/
   1. p.1
5. Sandia National Laboratories. (1993). B53-1 Special Study Report (SAND 93-0943; p. 48). Los Alamos National Laboratory. https://osf.io/46sfd/
   1. P.11
6. Consolidated Nuclear Security (CNS). (2016). Consolidated Nuclear Security, LLC. Performance Evaluation Report. National Nuclear Security Administration (NNSA). https://www.energy.gov/sites/default/files/2018/02/f48/fy_2016_cns_fdo_memo_publicly_releasable_per_0%5B1%5D.pdf
   1. p.8 (PDF Page)
7. Sandia National Laboratories. (1993). B53-1 Special Study Report (SAND 93-0943; p. 48). Los Alamos National Laboratory. https://osf.io/46sfd/
   1. p.5 (PDF Page)
   2. p.11 (PDF Page)
   3. p.21 (PDF Page)
8. Department of Energy FY2020 Congressional Budget Request; National Nuclear Security Administration—Federal Salaries and Expenses, Weapon Activities, Defense Nuclear Nonproliferation & Naval Reactors (DOE/CF-0150; p. 655). (2019). Office of the Chief Financial Officer. https://www.energy.gov/sites/prod/files/2019/04/f62/doe-fy2020-budget-volume-1.pdf
   1. p.91 (PDF Page)

1. Sandia National Laboratories. (2013, September 6). Lab News—Vol 65, No 16. Lab News, 65(16), 11. https://www.sandia.gov/app/uploads/sites/81/2021/07/labnews09-06-131.pdf
   1. p.9 (PDF Page)
2. Kristensen, H. M. (2005). US Nuclear Weapons in Europe: A Review of Post-Cold War Policy, Force Levels, and War Planning. National Resources Defense Council. https://www.nukestrat.com/pubs/EuroBombs.pdf
   1. p.21
3. National Nuclear Security Administration. (2019). Fiscal Year 2020 Stockpile Stewardship and Management Plan (p. 364) [Congressional Report]. Department of Energy. https://www.energy.gov/sites/prod/files/2019/08/f65/FY2020__SSMP.pdf
   1. p.350 (PDF Page)