209 Days

Thank you to all of those who are a shining light in the dark. 

Coming of age at a time of growing global tensions, there’s a new DOE program called ECSE. E is for Enhanced.  This strictly stockpile-science furthering activity helps assure DOE meets goals vis-a-vis reliability. The Enhanced DOE stewardship project is the latest historical development in the 25-year U.S. subcritical nuclear test program.                                                                                                                                                                                                                                


209 days


In Las Vegas, Nevada, millions of tourists each year are greeted by dazzling sights such as the half-size replicas of the Statue of Liberty and the Parisian Eiffel Tower.

Contrasting with these attractive mockups of the world's most iconic and admired structures are unannounced plutonium blast experiments -- called subcritical nuclear tests, involving scale models of nuclear warheads -- sporadically conducted at a restricted government site eighty miles northwest of the Strip.

When the Biden administration carried out its second subcritical nuclear experiment in September 2021, it remained a secret for 209 days.

209 days since the latest nuclear test on April 14, 2022

Excerpt from U.S. Sneaks In Vega, Its 28th Subcritical Nuclear Test:

In 1997, beginning with 'Rebound,' the Department of Energy started providing a 48-hour notification prior to each subcritical test to various governments, organizations, and the media. For over a decade, the Energy Department, and later the NNSA, consistently adhered to this policy of prior notifications and also issuing a press release within hours or a day of each test.

In September 2010, for its 24th subcritical nuclear test named 'Bacchus,' the NNSA abandoned its voluntary policy of providing a 48-hour notice and, months later, the agency first began to opt out of issuing a press release following a subcritical test. In fact, in late 2010 and early 2011, the NNSA conducted two subcritical tests, 'Barolo A' and 'Barolo B,' that were not followed up by any confirmatory announcements for months.'

After the NNSA conducted the Barolos-the 25th and 26th subcritical nuclear experiments or SNEs-in late 2010 and early 2011, news of the two SNEs was only first published in June 2011, delivered in tabulated form-without the Barolo name-appearing in an Administration PDF report. In 2022, President Biden's belated 209-day announcement for a 2021 subcritical nuclear test set a new record of SNEs non-transparency. 

Cold Shot / Cold Standby Status Updates at NNSS

The U.S. has conducted 32 subcritical nuclear experiments since the end of the Cold War to ensure the stockpile is resilient.

What is a subcritical nuclear test?


Subcritical nuclear tests are nuclear experiments designed to explosively bombard small amounts of weapon-grade plutonium-239.

Carried out by the National Nuclear Security Administration (NNSA) periodically in an underground alcove in the State of Nevada, the experiments, also dubbed ‘subcrits,’ do not reach a self-sustaining “critical” fission chain reaction.  However, several critical problems remain.

My PDF flyer (latest version):  'What are Subcritical Nuclear Tests?'

U.S. Subcritical nuclear tests

1997 - present  

2 July 1997, Rebound
18 September 1997, Holog
25 March 1998, Stagecoach
26 September 1998, Bagpipe
11 October 1998, Cimarron
9 February 1999, Clarinet
22 March 2000, Thoroughbred
14 February 2002, Vito 
7 June 2002, Oboe 9 
29 August 2002, Mario 
26 September 2002, Rocco 
19 September 2003, Piano 
25 May 2004, Armando 
23 February 2006, Krakatau
30 August 2006, Unicorn 
15 September 2010, Bacchus 
1 December, 2010, Barolo A
2 February, 2011, Barolo B
Scaled-----5 December, 2012, Pollux 
Scaled-----13 December, 2017, Vega
Scaled-----13 February, 2019, Ediza
Scaled-----3 November, 2020, Nightshade A
Scaled-----22 June, 2021, Nightshade B
Scaled------16 September, 2021, Nightshade C

Oboe (1) to Oboe 8 - conducted 1999-2001

Next subcritical test series: Nimble (three shot series planned thru 2026)

Update: On August 16, 2022, the NNSA announced that it completed a large infrastructure construction subproject at the NTS that could help with future subcritical nuclear tests. The NNSA said that the finished installations include 'structures, systems, and components necessary for deployment of the ECSE' [subcritical] program at the NTS. Per a press release, the subproject 'provides Access and Life Safety infrastructure..including a new access drift, a new Refuge Station, and necessary power and ventilation for mining new drifts.' The NNSA press release notes its Complex Enhancements project for U1a - completed ahead of time - 'closes a capability gap in the ability to certify changes to the stockpile.'