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Energy and permitting policy, read from the public record.

Register entry No. 0036ReportDocket No. 50-614; ML25090A057

NRC issues Long Mott construction permit No. CPAR-3 for four Xe-100 reactors, Docket No. 50-614, after denying intervenor review

The immediately effective permit, issued November 9, follows the Commission's November 6 order in CLI-26-15 denying San Antonio Bay Estuarine Waterkeeper's petition for review. Waterkeeper had challenged fuel testing, financing and flood analysis for the Calhoun County, Texas, plant.

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Summary

“The CP, which is immediately effective, authorizes LME to construct a power reactor facility in Calhoun County, Texas,” reads the Nuclear Regulatory Commission’s notice of issuance for Construction Permit No. CPAR-3, issued November 9, 2026, to Long Mott Energy, LLC under Docket No. 50-614 (Docket ID NRC-2025-0079) [1]. The notice is given under 10 CFR 2.106, cites the Atomic Energy Act of 1954 (42 U.S.C. 2011 et seq.) as authority, and is signed by Mehdi Reisi Fard, director of the Division of Advanced Reactor Engineering in the Office of Advanced Reactors [1]. Three days earlier, the Commission denied the last pending challenge in the contested case, San Antonio Bay Estuarine Waterkeeper’s petition for review, in CLI-26-15 [3, 4].

What the record shows

The facility is the Long Mott Generating Station, four X-energy Xe-100 small modular high-temperature gas-cooled reactors on Dow Chemical land next to Seadrift Operations, a Dow affiliate’s industrial plant [3]. Long Mott Energy is a wholly owned Dow subsidiary [3]. The NRC’s release says the plant will mainly produce high-temperature steam for Seadrift, with excess electricity exported to the grid [2]. World Nuclear News, citing X-energy, puts total output at 800 MWt or 320 MWe [6].

The notice lists the findings behind the permit. The NRC found:

  • that “there is reasonable assurance that the activities authorized by the permit will be conducted in compliance with the rules and regulations of the Commission” and “that safety questions will be satisfactorily resolved by the completion of construction” [1];
  • that the plant “can be constructed and operated at the proposed location without undue risk to public health and safety, subject to the conditions listed in the CP” [1];
  • that Long Mott Energy “is technically and financially qualified to construct the facility” [1];
  • that issuance complied with subpart A of 10 CFR part 51, the NRC’s NEPA regulations [1].

The supporting documents are in ADAMS. The notice lists the permit (ML26301A133), a Safety Evaluation dated October 30, 2026 (ML26295A004), and an environmental assessment and finding of no significant impact covering the permit and environmental review exemptions (ML26112A016) [1]. It also lists Revision 1 of the application, dated September 18, 2026, and two requests for confirmation of information, dated August 14 and September 14 [1].

The NRC’s release describes several firsts: its first approval of a multimodule advanced reactor facility, of a pebble-bed core, and of a design with online refueling, and its first review of a high-temperature gas-cooled reactor under the Licensing Modernization Project framework [2]. It calls CPAR-3 the third advanced reactor construction permit the agency has issued this year [2]. TVA’s Clinch River permit for a 300-megawatt GE Vernova Hitachi boiling-water reactor came on September 29 after a 14-month review [5].

Where it sits in the process

Long Mott Energy filed the application on March 31, 2025 [1]. Chairman Ho K. Nieh said the agency “delivered on the 18-month schedule” [2]. The release says staff finished the safety evaluation in October, “one month ahead of schedule,” and issued the environmental assessment in May [2]. The uncontested hearing, run under the NRC’s revised mandatory hearing procedures, was held September 22 in Port Lavaca, Texas [3]. This site’s August report on the hearing notice covers how that format was set.

How did the contested hearing end?

The contested case closed in stages. CLI-26-15 says the Licensing Board issued six decisions that “cumulatively rejected or dismissed all” of Waterkeeper’s contentions “and resulted in the termination of the adjudicatory proceeding” [3]. The sequence, as the Commission recounts it [3]:

Date Board action Subject
Jan. 22, 2026 LBP-26-1 grants standing, admits Contentions 3A and 3B in part Financial qualifications
Mar. 18 Denies motion to amend Contention 1 TRISO fuel testing schedule
Mar. 20 Dismisses Contention 3A as moot Grounds for a Part 50 exemption
Apr. 13 Denies new Contention 6 Flooding
June 25 LBP-26-4 denies amended 3B, dismisses 3B as moot Funding source
June 25 LBP-26-5 denies new Contention 3C Revised exemption grounds

Two things moved the financial dispute. On March 3, 2026, Long Mott Energy struck and replaced its rationale for an exemption from the Part 50 financial qualifications rules, and it filed a non-public agreement showing “a conditional commitment by Dow to fund at least 50% of the estimated construction costs” [3]. Before that, it had relied on a DOE Advanced Reactor Demonstration Program award to show funding, without filing the award itself [3]. The Board found that continuing discovery on Contention 3A, “even though there is nothing left to litigate,” would not serve judicial economy [3].

The Commission dismissed Long Mott Energy’s own appeal of LBP-26-1 as moot in CLI-26-10 on August 7 [3]. Waterkeeper petitioned on July 20 under 10 CFR 2.341(b) [3]. The staff requirements memorandum records that the Commission “has voted to approve a Memorandum and Order that denies the petition for review,” and that the Secretary signed it on November 6 [4]. The order states its conclusion plainly: “we deny the petition for review” [3].

Next, a construction permit “does not authorize operation,” and the company must obtain a separate operating license before loading fuel [2]. Court review runs through 28 U.S.C. 2344, which gives a party aggrieved by a final order reviewable under that chapter 60 days “after its entry” to petition a court of appeals [7].

What the record does not show

  • The permit conditions. The notice refers to “the conditions listed in the CP” without stating them [1]. Whether any condition addresses financing before construction starts is not in the notice or the release [1, 2].
  • The financial exemption. The notice finds Long Mott Energy financially qualified but does not say under which standard [1]. CLI-26-15 describes the company’s request for an exemption from 10 CFR 50.33(f) and Appendix C in favor of the “appears to be financially qualified” test in 10 CFR 70.23(a)(5) [3]. The order notes that the Commission has proposed writing that test into Parts 50 and 52 (91 FR 60702) [3]. The record cited here does not say whether the exemption was granted.
  • The Dow agreement’s terms. The dollar amounts and contract terms are redacted; the Board described the agreement only in general terms [3].
  • Fuel qualification. The application’s latest construction completion date is 2033, and 10 CFR 50.34(a)(8) requires research needed to confirm the design to be finished before that date [3]. The Commission resolved Contention 1 on pleading grounds, not on whether the TRISO fuel testing schedule can be met [3].
  • Court review. No petition appears in the record this report draws on, and the record does not say whether any party treats CLI-26-15 or the permit as the order it would challenge.

Positions on the record

The NRC. Nieh’s statement in the release: “Today, the new NRC is issuing America’s first construction permit for a high-temperature gas-cooled reactor in more than half a century” [2]. The agency said the review proves “we can do rigorous safety reviews on predictable timelines” [2].

The NRC staff and the applicant. Both filed answers opposing Waterkeeper’s petition for review [3]. The staff told the Board it would not take part as a party on Contentions 3A and 3B [3]. X-energy’s Chief Global Operating Officer Dragan Popovic said after the safety evaluation that “Licensing a new reactor is earned through the quality of the application and the rigor of the regulator’s review,” according to World Nuclear News [6].

The intervenor. Waterkeeper, a Seadrift-based nonprofit, argued that the Board read its contentions so narrowly that Long Mott Energy could “easily moot” them by supplementing the application [3]. On financing, it argued that the company is unlikely to enforce an agreement against Dow, its ultimate parent, and that the Dow supplement “offered little additional, meaningful information” [3]. Its expert, Edwin Lyman, said finishing fuel testing by 2033 was not “reasonably achievable” given the lack of “as-manufactured” TRISO fuel [3]. On flooding, Waterkeeper argued that the Board set the admissibility bar so high it would have had to run its own computer models [3].

The Commission. It answered that its admissibility standards are “strict by design” [3]. On one point it sided partly with Waterkeeper, writing that it was “difficult to square” the Board’s finding that the factual basis for an amended fuel-testing contention existed at the outset, since the fuel testing schedule “did not exist when Waterkeeper filed its hearing request” [3]. It upheld the denial anyway, because the amended contention still cited no regulatory basis for testing “as manufactured” fuel [3]. On flooding, it noted that the hydrology supplement set the design basis hazard level at 46.49 feet above sea level and that Waterkeeper did not contest the storm surge analysis that fixed it [3].

Reading-room questions

Questions readers bring to this record, answered from the documents cited below.

Has the NRC approved the Long Mott nuclear plant in Texas?
The NRC issued Construction Permit No. CPAR-3 to Long Mott Energy on November 9, 2026, and the permit is immediately effective [1]. It authorizes construction only; operation requires a separate operating license [1, 2].
What happened to Waterkeeper's challenge to the Long Mott permit?
The Licensing Board rejected or dismissed all of San Antonio Bay Estuarine Waterkeeper's contentions and terminated the proceeding by June 25, 2026 [3]. On November 6 the Commission denied Waterkeeper's petition for review of six Board decisions in CLI-26-15 [3, 4].
Who is paying to build the Long Mott Generating Station?
Long Mott Energy is a wholly owned Dow subsidiary [3]. In March 2026 it filed a non-public agreement showing a conditional Dow commitment to fund at least 50 percent of estimated construction costs, replacing its earlier reliance on a DOE Advanced Reactor Demonstration Program award to show funding [3].
When must Long Mott construction be finished under the application?
The latest construction completion date cited in the application is 2033, according to CLI-26-15 [3]. Under 10 CFR 50.34(a)(8), research needed to confirm the design must be finished before that date [3].
Can the Long Mott construction permit be challenged in court?
Under 28 U.S.C. 2344, a party aggrieved by a final order reviewable under that chapter has 60 days after its entry to petition a court of appeals [7]. The record cited here does not show whether Waterkeeper or anyone else will file [1, 3].

Note on sourcing

This report relies on the public inspection copy of the NRC's notice of issuance, FR Doc. 2026-23029, filed November 10 and scheduled for Federal Register publication November 12; the published text and page citation could differ. The permit itself (ADAMS No. ML26301A133), the October 30 Safety Evaluation and the permit conditions they set out are not described here beyond what the notice and the NRC's news release state. CLI-26-15 discusses the Licensing Board's decisions as the Commission summarized them; this report does not draw on the Board orders directly, and the Dow funding agreement's dollar amounts are non-public. The notice's document table dates the environmental assessment May 31, 2026; the NRC's release says only that it issued in May. The 320 MWe figure and the X-energy statement are as World Nuclear News reported them. Neither Long Mott Energy, Dow nor San Antonio Bay Estuarine Waterkeeper had made a statement on the permit in the record this report draws on, and that record does not show whether any party intends to seek court review.

Sources

  1. Long Mott Energy, LLC; Long Mott Generating Station; Construction Permit, notice of issuance, Docket No. 50-614, NRC-2025-0079 (FR Doc. 2026-23029, public inspection copy, filed November 10, 2026)Nuclear Regulatory Commission, November 10, 2026 · public-inspection.federalregister.gov
  2. NRC Issues First Construction Permit in Nearly 60 Years for High-Temperature Gas-Cooled Reactor (News Release No. 26-083)Nuclear Regulatory Commission, November 9, 2026 · nrc.gov
  3. Long Mott Energy, LLC (Long Mott Generating Station), CLI-26-15, Memorandum and Order, Docket No. 50-614-CPNuclear Regulatory Commission, November 6, 2026 · nrc.gov
  4. Staff Requirements, Affirmation Session, November 6, 2026, SECY-26-0124 (M261106)Nuclear Regulatory Commission, November 6, 2026 · nrc.gov
  5. NRC Approves Construction of Nation's First Small Modular Reactor (News Release No. 26-079)Nuclear Regulatory Commission, September 29, 2026 · nrc.gov
  6. Texas SMR plant moves to final permitting stageWorld Nuclear News (World Nuclear Association), November 2, 2026 · world-nuclear-news.org
  7. 28 U.S. Code § 2344, Review of orders; time; notice; contents of petition; serviceU.S. Congress, accessed 2026-11-11 · law.cornell.edu

Subject headings

Cross-references

Other register entries filed under the same subject headings.

  1. No. 0016 · Report · 6 shared headingsNRC sets Sept. 22 mandatory hearing on Long Mott Xe-100 construction permit, 91 FR 53900
  2. No. 0027 · Rule · 2 shared headingsNRC renews AP1000 design certification by direct final rule, adopting Revision 20, 91 FR 65091
  3. No. 0019 · Report · 2 shared headingsNRC notices NextEra-Dominion application for indirect transfer of Dominion nuclear licenses, NRC-2026-4060