On 9 January 2017, Gizmodo published an article reporting that President-elect Donald Trump had dismissed "the people in charge of maintaining our nuclear arsenal":
Between the Trump transition team’s infighting, incompetence, and high-profile resignations, any decisions that signaled even a modicum of stability for the country would come as a relief at this point. Unfortunately, the nascent Trump Administration isn’t inclined to calm anyone’s nerves. According to an official within the Department of Energy, this past Friday, the President-elect’s team instructed the head of the National Nuclear Security Administration and his deputy to clean out their desks when Trump takes office on January 20th.
The NNSA is the $12 billion-a-year agency that “maintains and enhances the safety, security, and effectiveness of the U.S. nuclear weapons stockpile.” It’s unclear when the two officials will be replaced. Their offices will remain vacant until they are.
Traditionally, all political appointees of an outgoing presidential administration turn in resignation letters effective on noon of inauguration day, January 20. But appointees in key positions — like the people who make sure our nukes work — are often asked to stay on in their roles until a replacement can be found and confirmed by the Senate, helping ensure a smooth transition and allowing our government to continue functioning. In fact, for the entirety of Obama’s first term and into part of his second, the NNSA Administrator remained a Bush appointee.
... As far as I can tell, this is unprecedented — January 20 will mark the first time in the NNSA’s 17-year history that it will exist wholly without its appointed leadership. According to Bob Rosner, the Co-Chair of the Science and Security Board of the Bulletin of the Atomic Scientists and the former director of Argonne National Laboratory, the leadership vacuum won’t prevent the agency from fulfilling its essential duties. But it will leave it without an advocate as it tries to secure a budget from Congress, and unable to tackle any new initiatives whatsoever.
The article's implications were difficult to miss:
Gizmodo's reporting was based on unnamed source within the Department of Energy and termed the Trump transition team's actions in not temporarily retaining the current National Nuclear Security Administration (NNSA) heads beyond the end of the current administration as "unprecedented." The article was later updated to note:
Correction, 1/9/17, 11:03 p.m.: Another NNSA official, speaking on background to Gizmodo and Defense News, has disputed this report as “inaccurate” while confirming that “there have been no discussions between the president-elect’s transition team and any of NNSA’s political appointees on extending their public service past Jan. 20.” In other words, the Trump transition team has not asked the top two NNSA officials to stay on until they can be replaced.
After speaking to our source for clarification, we have updated the story and headline to reflect that, while Klotz and Creedon have submitted their resignations, intend to depart on January 20, and have not been asked by the Trump transition to stay past that date, the Trump team has not explicitly instructed them to leave or “clean out their desks,” as we reported. According to our source, both officials “have expressed [to the Trump team] that they would likely be willing to stay to facilitate a smooth transition, if asked,” as is the tradition for key officials, and have received no response.
An article subsequently published by DefenseNews quoted an NNSA official who maintained the original report was "not accurate":
Gizmodo reported that the Trump team has asked NNSA director Frank Klotz and his deputy, Madelyn Creedon, to step down on Jan 20. Because those positions require senate confirmation, those spots would likely be open for several weeks, if not months — at a time when the agency would need to be advocating the new Congress for funding.
However, an NNSA official, speaking on background, denied such discussions have occurred.
“The story is not accurate,” the official said. “There have been no discussions between the president-elect’s transition team and any of NNSA’s political appointees on extending their public service past Jan. 20.”
The other party involved in the claim (i.e., Trump's transition team) disputed the issue as well:
A representative from the Trump transition team also disputed Gizmodo's story, though it's unclear what was being disputed. "There is no validity to this," the representative wrote in an email to Business Insider while declining to answer multiple questions about details in the piece.
A relatively youthful agency established at the tail end of President Bill Clinton's second term in 1999, the NNSA has had just four administrators in its history (leaving little transition-related history to examine). According U.S. Code § 7132, the NNSA's Under Secretary is appointed by the President for what was originally a term of three years. The NNSA's first Under Secretary John A. Gordon, who served for two years, followed by Linton Brooks (who was asked to resign in 2007). Replacement Tom D'Agostino served under Presidents George W. Bush and Barack Obama between 2007 and 2014, then was replaced by then-current Under Secretary Frank Klotz.
Journalist Jeffrey Lewis tweeted about the 2017 transition-related rumors, noting that precedent regarding the NNSA was minimal:
No precedent. George W. Bush kept Clinton appointee John Gordon into mid-2002; Obama kept Bush appointee Tom D'Agostino until 2014. https://t.co/UEcrtcoXjG
— Jeffrey Lewis (@ArmsControlWonk) January 9, 2017
"Though it's unclear what was being disputed" seems to sum up this story. The issue at hand appears to be, in a functional sense, a distinction without a difference: either Trump's transition team has affirmatively ordered the NNSA leadership to vacate their posts, or Trump's transition team is passively allowing the NNSA leadership to leave their posts by not taking any specific actions to retain them — but either way, unless something changes, that leadership will be gone come 20 January 2017. Whether this course of events can accurately be described as "unprecedented" is something of a subjective issue, as existing precedent is rather slight.