ML24269A212
| ML24269A212 | |
| Person / Time | |
|---|---|
| Site: | Hermes File:Kairos Power icon.png |
| Issue date: | 09/25/2024 |
| From: | Carrie Safford NRC/SECY |
| To: | NRC/OCM |
| SECY RAS | |
| References | |
| RAS 57125, 50-611-CP, 50-612-CP | |
| Download: ML24269A212 (0) | |
Text
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
In the Matter of KAIROS POWER LLC Docket Nos. 50-611-CP 50-612-CP (Hermes 2 Test Reactor Facility)
ORDER
(Transmitting Hearing Questions)
On September 12, 2024, the Commission issued a notice that it is holding a hearing
pursuant to section 189a. of the Atomic Energy Act of 1954, as amended, to receive written
evidence in the form of testimony and exhibits in the uncontested portion of the captioned proceeding.1 In connection with that hearing, pursuant to my authority under 10 C.F.R.
§ 2.346(a) and (j), Kairos Power LLC and the NRC Staff should file written responses to the
questions provided in the table below. Responses should be filed by October 10, 2024.
1 See Kairos Power LLC; Notice of Hearing, 89 Fed. Reg. 74,303 (Sept. 12, 2024).
Table of Questions
No. Category Reference Directed Question To
1 Safety - Hermes 2 Non -Power Reactor Applicant PSAR Section 2.2.2.4, Summary of Risks from Air Aircraft Impact Preliminary Safety Analysis Staff Traffic, states that DOE-STD-3014-2006 provides a Report, Revision 1 (May 2024) screening value for which the risk of an aircraft accident (ML24144A092) (PSAR) is considered acceptable. The PSAR further notes that the total crash frequency for all airway, helicopter Safety Evaluation Related to operations, airport takeoff operations, and airport landing the Kairos Power LLC operations at the Hermes 2 facility exceeds this criterion.
Construction Permit Application Given this, PSAR Section 2.2.2.4 states that the safety-for the Hermes 2 Test Reactor related portion of the Reactor Building structure will be Facility Dockets 50-611 & designed to withstand the impact of a small non-military 50-612 (July 2024) general aviation aircraft as described in Section 3.5.
(ML24200A115) (SE) PSAR Section 3.5.3.4 states that the design of the safety-related portion of the Reactor Building is evaluated for the NRC Staff Responses to effects of aircraft impact from light general aviation Commission Pre-Hearing aircraft, rather than a specific aircraft.
Questions in the Matter of Kairos Power LLC (Hermes Test Section 2.2.3.1 of the Staffs SE states that [t]he staff will Reactor), Docket review the basis for selecting the critical aircraft type for No. 50-7513-CP (Sept. 28, designing the safety-related portion of the reactor 2023) (ML23271A250) buildings during a future review of the operating license (OL) application of the Hermes 2 facility. No further Kairos Power LLCs Responses aircraft type information is provided in the SE.
to Commission s Pre-Hearing Questions in the Matter of In response to pre-hearing question number 7 during the Kairos Power LLC (Hermes Test Hermes 1 construction permit mandatory hearing, Kairos Reactor), Docket No. 50-7513 suggested that over 90% of projected flight operations (filed Sept. 28, 2023) would be general aviation aircraft such as a Cessna (ML23271A184) 172R (single engine) or Beechcraft Baron 58P (multi-engine). By contrast, in its response to the same pre-DOE-STD-3014-2006, Accident hearing question, the Staff stated that it expects that Analysis for Aircraft Crash into aircraft characteristics similar to those of the Beechcraft Hazardous Facilities,
May 2006 King Air 350i may be used in establishing the aircraft (https://www.standards.doe.gov/ impact design basis for the reactor building.
standards-documents/3000/3014-astd-Given the significant differences in the speed and weight 2006) of the aircraft referenced by Kairos and the Staff for the Hermes 1 review combined with the high likelihood that substantial portions of the safety-related portions of the reactor buildings will be designed and built by the time of the operating license review, please address the following:
(a) For the Staff and Applicant: What basis do you plan to use during the operating license phase of Hermes 2 to determine the acceptable aircraft type for the purpose of designing the safety-related portions of the reactor buildings?
(b) For the Staff: Given that the selection of the critical aircraft type for designing the safety-related portion of the reactor buildings is being deferred to a future review of the operating license, explain why it is acceptable to defer this design input for a safety-related structure until the operating license review stage. Specifically, discuss the basis of the finding that the preliminary design of the Hermes 2 facility provides reasonable assurance that the final design will conform to the design basis, includes an adequate margin of safety, describes the structures, systems, and components which will provide for the prevention of accidents and the mitigation of consequences of accidents, and meets all applicable regulatory guidance and satisfies applicable NRC guidance.
2 Safety - Hermes 2 Non-Power Reactor Applicant PSAR Section 2.4, Hydrology, for the Hermes 2 facility Flooding Preliminary Safety Analysis Staff incorporated only minor changes compared to the Report, Revision 1 (May 2024) Hermes 1 PSAR (all related to references to the two -unit (ML24144A092) (PSAR) Hermes 2 facility). As noted in Section 2.4 of the Staffs SE, a difference between Hermes 1 and Hermes 2 is that Safety Evaluation Related to the intended licensing period is increased from 4 years to the Kairos Power LLC 11 years. Section 2.4.3.1 of the SE further notes:
Construction Permit Application for the Hermes 2 Test Reactor The Hermes 1 SE describes staffs evaluation and Facility Dockets 50-611 & findings with regard to dam safety during the 50-612 (July 2024) facilitys 4-year operating lifetime. The staffs (ML24200A115) (SE) findings are applicable to Hermes 2s longer operating lifetime of 11 years because the ongoing NRC Staff Responses to oversight and inspections carried out by the Commission Pre-Hearing Tennessee Valley Authority (TVA) as part of its Questions in the Matter of dam safety program will continue throughout the Kairos Power LLC (Hermes Test 11-year proposed licensing term of Hermes 2, Reactor), Docket No. providing the staff with reasonable assurance that 50-7513-CP (Sept. 28, 2023) a dam failure resulting in site flooding would be (ML23271A250) very unlikely.
However, in response to pre-hearing question number 8 during the Hermes 1 construction permit mandatory hearing, the Staff stated:
For flooding hazards from potential dam failures, consideration of a limited operating life was necessary to approve the siting because the Staff did rely on the 4-year operating period, in part, to assess the suitability of the site.
The Staff also noted in response to pre-hearing question number 9 that:
This determination was also based on the limited (4-year) period of Hermes operation combined
with the lower risks associated with management and operations programs of the responsible federal agency for relevant dams in the vicinity of the proposed Hermes site. Tennessee Valley Authority owns, operates, and regularly inspects the dams following the requirements of its dam safety program. This oversight further supports Staffs determination that sunny-day failure of the dams would be unlikely.
(a) For the Staff and Applicant: Has the Tennessee Valley Authority made any changes in its oversight of dams in the vicinity of the proposed Hermes 2 site to permit the longer operating term of 11 years rather than 4 years? If so, please describe the changes.
(b) For the Staff: Section 2.4.3.1 of the SE states that that a sunny day dam failure is not considered a credible hazard for a 4-year or an 11-year operating lifetime and that that the staff finds that the proposed 11-year operating lifetime is acceptable with regard to site hydrology. What was the Staffs specific basis for determining that this hazard was not credible and that the site hydrology was acceptable for the proposed operating license term? Is the basis used by the Staff broadly applicable to all Part 50 licensed facilities or to a certain subset, such as non-power reactors?
3 Safety - Hermes 2 Non-Power Reactor Applicant Section 5.2.1.2 of the Hermes 2 PSAR states that the Intermediate Preliminary Safety Analysis Staff Intermediate Heat Transport System (IHTS) is equipped Heat Report, Revision 1 (May 2024) with safety-related rupture disks located in the Exchanger (ML24144A092) (PSAR) intermediate inert gas subsystem, in the gas space above Rupture Disks the Intermediate Salt Vessels.
Letter from Walter Kirchner, ACRS, to Christopher Hanson,
NRC, Safety Evaluation of the As described in Section 3.6.3.2 of the Staffs SE, The Kairos Non-Power Reactor rupture disks are used to prevent overpressure in the Hermes 2 Construction Permit IHTS during a postulated superheater tube leak or Application, (July 17, 2024) rupture event. The rupture disk standpipes and vent lines (ML24197A152) would also provide a relief path for the steam from a superheater tube rupture to prevent the steam from Safety Evaluation Related to reaching the [Intermediate Heat Exchanger (IHX)]. While the Kairos Power LLC the IHX, including the IHX tubes, are classified as non-Construction Permit Application safety related, the staff noted that failure of one or more for the Hermes 2 Test Reactor IHX tubes following a superheater tube rupture could lead Facility Dockets 50-611 & to unanalyzed conditions due to potential Flibe-water 50-612 (July 2024) interactions or higher than assumed levels of BeNaF (ML24200A115) (SE) ingress into the PHTS [Primary Heat Transfer System].
10 C.F.R. §§ 50.34, 50.35(a)(3) In its letter of July 17, 2024, the ACRS noted that the safety-related rupture disks are proposed by Kairos to prevent the pressure rise associated with a superheater tube rupture from reaching the point where the tubes in the IHX fail. Further, the ACRS stated:
The design of the passive rupture disks in the intermediate coolant loop and the time needed for disks to actuate (relative to the event-generated pressure wave and the speed of sound in the salt) will be critical in mitigating the progression of this event and limiting overall damage. In light of the uncertainties associated with the progression of this postulated event, we believe strong preventive measures are preferred over mitigative ones. Were Kairos to be unsuccessful in designing the rupture disks to protect the IHX tubes, the safety classification of the IHX, the intermediate loop, or both may have to be reconsidered.
In Section 13.1.10.3.2 of the SE, the Staff acknowledged the uncertainties: In the absence of any explicit modeling or experimental data, the staff finds that there is large uncertainty in the progression of events following a postulated superheater tube break or rupture.
10 C.F.R. § 50.34(a)(8) requires that the PSAR include, in part, identification of those structures, systems or components (SSCs) which require research and development to confirm the adequacy of their design; and identification and description of the research and development program which will be conducted to resolve any safety questions associated with such SSCs; and a schedule of the research and development program showing that such safety questions will be resolved at or before the latest date stated in the application for completion of construction of the facility. PSAR Section 1.3.9, Research and Development, identifies SSCs that require additional research and development; however, this section does not discuss design of the IHTS safety-related rupture disks.
(a) For the Staff and Applicant: Is additional research and development needed to produce a final design of the IHTS rupture disks to ensure that design bases are met?
(b) For the Staff and Applicant: If the answer to part (a) is yes, what research and development activities are required and what is the schedule for their completion?
(c) For the Staff: Although the two facilities have different operating lifetimes, the items related to Chapter 4 included in Appendix A.3 (Research and Development Items) of the Staff SE are identical for
Hermes 1 and 2. Based on the discussion in Chapter 4.3 of the Staff SE (e.g., for the reactor vessel and graphite), the Commission understands that the qualification for these SSCs is more substantial than that proposed for Hermes 1 due to the longer proposed operating lifetime for Hermes 2. Does the Staff consider the additional qualification activities needed to confirm material performance for a longer operating lifetime research and development under 10 CFR 50.34(a)(8) that must be resolved prior to the latest date of construction for Hermes 2?
4 Environmental 10 C.F.R. § 51.105(a)(1) Staff Pursuant to 10 C.F.R. § 51.105(a)(1), the Commission
- Commission must determine in this proceeding whether the Findings National Environmental Policy requirements of NEPA section 102(2)(C) have been met.
Act (NEPA) § 102(2)(C)(v),
42 U.S.C. § 4332(C)(v) NEPA section 102(2)(C)(v) requires an agencys environmental review to consider any irreversible and National Environmental Policy irretrievable commitments of Federal resources which Act Implementing Regulations would be involved in the proposed agency action should it Revisions Phase 2; 89 Fed. be implemented. The Council on Environmental Quality Reg. 35,442, 35,507 (May 1, interprets the phrase Federal resources to plainly mean 2024) resources owned by the Federal Government or held in trust for Tribal Nations.
Environmental Assessment and Finding of No Significant The Staff states in its Information Paper that the EA Impact for the Construction addresses any irreversible and irretrievable Permits and Environmental commitments of Federal resources that would be involved Review Exemptions for the in the proposed action should it be implemented.
Kairos Hermes 2 Test Reactors However, while EA section 5.3.3 discusses irreversible (Final Report) (Aug. 2024), and irretrievable commitments of resources, it does not
§ 5.3.3 (ML24240A034) (EA) identify which, if any, of these are Federal resources.
Staffs Statement in Support of the Uncontested Hearing for Issuance of Construction
Permits for the Kairos Hermes 2 Please clarify:
Test Reactor Facility, Commission Paper (a) Whether the Staff has identified any irreversible and SECY-24-0075 (Sept. 5, 2024), irretrievable commitments of Federal resources that at 20 (ML24152A258) would be involved in implementing the proposed (Information Paper) agency action.
(b) If any such Federal resources have been identified, how they have been addressed in the EA.
For the Commission
Carrie M. Safford Secretary of the Commission
Dated at Rockville, Maryland, this 25th day of September 2024.
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
In the Matter of )
)
KAIROS POWER, LLC ) Docket No. 50 -611-CP
) 50- 612-CP (Hermes 2 Test Reactor Facility) )
)
(Mandatory Hearing) )
CERTIFICATE OF SERVICE
I hereby certify that copies of the foregoing ORDER (Transmitting Hearing Questions) have been served upon the following persons by Electronic Information Exchange.
U.S. Nuclear Regulatory Commission Counsel for Kairos Power, LLC Office of Commission Appellate Adjudication Morgan, Lewis & Bockius, LLC Mail Stop: O-16B33 1111 Pennsylvania Ave NW Washington, DC 20555-0001 Washington, DC 20004 E-mail: ocaamail.resource@nrc.gov Ryan Lighty Alex Polonsky U.S. Nuclear Regulatory Commission Molly Mattison Office of the Secretary of the Commission E-mail: ryan.lighty@morganlewis.com Mail Stop: O-16B33 alex.polonsky@morganlewis.com Washington, DC 20555-0001 molly.mattison@morganlewis.com E-mail: hearingdocket@nrc.gov
U.S. Nuclear Regulatory Commission Office of the General Counsel Mail Stop - O-14A44 Washington, DC 20555-0001 Susan Vrahoretis Anita Ghosh-Naber David Roth Megan Wright Caitlin Byrd E-mail: susan.vrahoretis@nrc.gov anita.ghoshnaber@nrc.gov david.roth@nrc.gov megan.wright@nrc.gov caitlin.byrd@nrc.gov
Office of the Secretary of the Commission Dated at Rockville, Maryland, this 25th day of September 202 4.