In response to Freedom of Information Act (FOIA) requests, DOE’s NNSA forced to release technical report that does not support a rapid return to production of plutonium “pits” (weapons cores) for new nuclear warheads. We conclude that the $30-billion building at the Savannah River Site (SRS) being prepared for a rapid, full-scale production of up to 125 plutonium pits per year plutonium – in preparation for full-scale nuclear war and not deterrence – should be placed on hold.
Nuclear Watch New Mexico and the Union of Concerned Scientists received these documents:
JASON report on plutonium pit aging, March 25, 2026, provided in response to a FOIA request to Nuclear Watch New Mexico and the Union of Concerned Scientists, provided by NNSA on August 7, 2026: JASON Plutonium Aging Executive Summary, Unclassified_Redacted-2 FPIA response August 7 2026
Totally redacted JASON report originally provided in response to FOIA request to NNSA, received July 2026 – a sad joke: JASON Plutonium Aging Executive Summary, Unclassified_Redacted provided July 15 2026
SRS Watch take on the JASON “Plutonium Aging” report of March 2026, reluctantly provided due to requests under FOIA (which has been decimated by DOE):
The 2-page summary of the March 2026 “Plutonium Aging” technical report by the JASON group, research arm of NNSA, initially withheld in its entirety in response to a FOIA request by Nuclear Watch New Mexico and the Union of Concerned Scientists, includes significant implications on the need, or not, for new plutonium pit production and plutonium pit reuse.
A redacted copy of the full report should be released but we doubt it will be. NNSA even attempted to withhold the summary, initially redacting the entire text in response to FOIA requests, but such redaction was unjustified and NNSA was forced to release the full text of the summary.
Those who commented on the draft plutonium pit-production Programmatic EIS (PEIS) asked that this report be provided for the record and before the end of the comment period (July 16). For us plaintiffs in the PEIS lawsuit, including SRS Watch, the South Carolina Environmental Law project (SCELP) sent a letter on our behalf to NNSA on July 6, 2026 and asked for various documents to be immediately released, including the 2026 JASON report:
“A new plutonium pit life study by independent scientists known as the JASONs. NNSA claims that potential aging effects drive the need for the immediate production of new pits, thereby ruling out the alternative of reusing some 15,000 existing pits. In contrast, a 2006 JASON pit life study concluded that most pit types have reliable lives of more than 100 years and those that don’t have relatively easy fixes (the average pit age is now ~43). We believe that NNSA has been withholding an unclassified summary of the new JASON pit life study since the end of 2025. NNSA has not released it despite requests by Members of Congress and public Freedom of Information Act requests.“
NNSA ignored the SCELP request.
(SCELP letter at: https://www.scelp.org/news/plaintiffs-demand-release-of-critical-documents-and-extension-of-public-comment-period-on-expanded-plutonium-bomb-core-production)
As background, the JASON report on “Pit Lifetime” from 2006 – https://nukewatch.org/oldsite/facts/nwd/JASON_ReportPuAging.pdf – stated, concerning pit aging, that “most primary types have credible minimum lifetime in excess of 100 years as regards aging of plutonium; those with assessed minimum lifetimes of 100 years or less have clear mitigation paths that are proposed and/or are being implemented.” NNSA avoids discussion of this and hasn’t presented any facts that undermine this conclusion.
In 2019, the JASON group issued a brief “letter report” – https://irp.fas.org/agency/dod/jason/pit-aging.pdf – that concluded “we urge that pit manufacturing be re-established as expeditiously as possible in parallel with the focused program to understand Pu aging.”
The key findings of the 2026 JASON report are:
1. “Overall, the results from the first five years of the Plan [on plutonium and pit aging] show that there are gradual changes in Pu material properties as a function of age, at a level that do not call into question present weapons performance.” The report further states: “The Pu in the stockpile appears to be aging slowly. The degradation issues that have been observed do not call into question present weapons performance.”
2. Most importantly related to pit aging, NNSA should continue research on the matter and “prioritize” “subcritical” tests, underground at the Nevada National Security Site, to better inform the pit aging research. A research plan of “work needed in FY31-40“on Pu aging should be executed. The report does not say the priority should be new pit production.
From the 2-page summary: “NNSA and its Laboratories must prioritize execution of subcritical experiments at ECSE if possible before FY30 and no later than FY35, along with establishing pit production capabilities that may be needed to provide options to mitigate any future aging-related issues.”
3. The 2026 report does not affirm the 2019 conclusion of the JASON group to re-establish pit production “as expeditiously as possible” but simply says that pit-production “capabilities that may be needed” should be pursued. This is no ringing endorsement of NNSA’s current plan to urgently produce up to 205 plutonium pits per year at Los Alamos and SRS, as presented in the draft Programmatic EIS.
Given on-going research and no current “degradation” in weapons performance, the implication of the JASON report is that there is ample time to continue research before a decision is made on expanded pit production.
And, the 2026 2-page summary does not question the 2006 JASON finding that pits can last 100 years or more. (Those pits would have been made at DOE’s now-closed Rocky Flats Plant in CO.)
Here are conclusions, on that PEIS plaintiff SRS Watch draw from the report:
That NNSA has dragged its feet on releasing the report clearly reveals that it does not want information in the public realm that runs contrary to its rhetoric about an urgent need for pit production at two DOE sites, Los Alamos and Savannah River Site. It remains the case that pits can last 100 years or more and that existing pits show no degradation in performance in a nuclear warhead, which makes the case that no new pit production is needed.
This JASON plutonium aging report report should have been released during the comment period for the draft Programmatic EIS on plutonium pit production. Failure to have released it has denied the public the right to assess the findings of the report and ability to comment on it for the record. NNSA should now accept additional comments into the PEIS record to correct the error it made.
The report does not affirm the current path that NNSA is now on concerning pit production – that such production be rapidly pursued, at great expense. Rather, the report affirms continuation of a measured, scientific research program concerning while leaving open the question if actual production of new pits is needed in the future.
As a large part of the basis for new pit production has been due to issues related to plutonium aging, this report undermines NNSA’s claim that pits are aging rapidly such that a massive infrastructure be implemented quickly to produce new pits for new nuclear warheads for which there is no demonstrated need. Thus, NNSA’s justification for new pit production is now subtly questioned by its own research body. Congress should take the findings of the report into account in its funding decisions.
The report does not validate the fast-paced track that NNSA is on concerning pit production at SRS, leading me to conclude that production efforts at SRS must be slowed down as pit aging research continues and new findings are resented on both new pit production and reuse of existing pits now in storage. The facility at SRS currently being prepared to produce pits has been cleared of equipment and prepared for future construction, so now is a good time to place that facility on hold until such time that NNSA can publicly present technical and scientific justification that new pits are needed. In the meantime, diligent efforts must be renewed among nuclear weapons states for continued disarmament and a halt to production of provocative new weapons.
Tom Clements
Director, Savannah River Site Watch
Columbia, SC