1CAN042501, Response to Request for Additional Information - Request for Review and Approval of Changes to the Safety Analysis Report and to a Confirmatory Order Clarifying an Alternate Means of Compliance for Pressurizer Heaters Emerge
| ML25098A194 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/08/2025 |
| From: | Couture P Entergy Operations |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 1CAN042501 | |
| Download: ML25098A194 (1) | |
Text
Entergy Operations, Inc., 1340 Echelon Parkway, Jackson, MS 39213 1CAN042501 10 CFR 50.90 April 8, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Response to Request for Additional Information - Request for Review and Approval of Changes to the Safety Analysis Report and to a Confirmatory Order Clarifying an Alternate Means of Compliance for Pressurizer Heaters Emergency Power Supply Arkansas Nuclear One - Unit 1 NRC Docket Nos. 50-313 Renewed Facility Operating License No. DPR-51 Pursuant to 10 CFR 50.90, Entergy Operations, Inc. (Entergy), requested an amendment to the Renewed Facility Operating License Number DPR-51 for Arkansas Nuclear One, Unit 1 (ANO-1) (Reference 1). Entergy requested the Nuclear Regulatory Commissions (NRC's) review and approval of a change to the ANO-1 Safety Analysis Report (SAR) and to the Confirmatory Order to implement all "Category A" lessons learned requirements by January 31, 1980, for ANO-1. The changes address manual actions outside the control room to restore emergency power to the pressurizer heaters. These actions are required due to the plant's design.
The NRC staff determined that additional information was needed to complete its review. The requests for additional information (RAIs) were transmitted via Reference 2. Reference 3 provided the response to the RAIs.
A second set of RAIs were determined to be required by the NRC. They were transmitted in final form to Entergy on March 19, 2025 in Reference 4. During a clarification call regarding the RAIs, Entergy agreed to provide responses to this second set of RAls by April 18, 2025.
Enclosed are the responses to the second set of RAIs. This letter contains no new regulatory commitments.
Entergy has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, which was previously provided to the NRC in Reference 1. Entergy has concluded that the information provided in this RAI response does not affect the bases for concluding that the proposed license amendments do not involve a Phil Couture Senior Manager Fleet Regulatory Assurance - Licensing Tel 601-368-5102
1CAN042501 Page 2 of 2 significant hazards consideration under the standards set forth in 10 CFR 10.92. In addition, Entergy has concluded that the information in this RAI response letter does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendments.
If there are any questions or if additional information is needed, please contact Riley Keele, Manager, Regulatory Assurance, Arkansas Nuclear One, at 479-858-7826.
I declare under penalty of perjury that the foregoing is true and correct. Executed on April 8, 2025.
Respectfully, Phil Couture PC/rwc
Enclosure:
Response to Request for Additional Information
References:
- 1. Entergy letter to NRC, "Request for Review and Approval of Changes to the Safety Analysis Report and to a Confirmatory Order Clarifying an Alternate Means of Compliance for Pressurizer Heaters Emergency Power Supply,"
(ADAMS Accession No. ML24184B775), (1CAN072401), dated July 2, 2024.
- 2. NRC (Dennis Galvin) electronic correspondence to Entergy (Riley Keele, Jr.),
"Arkansas Nuclear 1 - Request for Additional Information - Request for Review and Approval Changes to SAR and to a Confirmatory Order - PZR HTR Emergency Power Supply (EPID L-2024-LLA-0092," (ADAMS Accession No. ML25029A006), (1CNA012502), dated January 28, 2025.
- 3. Entergy letter to NRC, "Response to Request for Additional Information -
Request for Additional Information - Request for Review and Approval of Changes to the Safety Analysis Report and to a Confirmatory Order Clarifying an Alternate Means of Compliance for Pressurizer Heaters Emergency Power Supply," (ADAMS Accession No. ML25057A318), (1CAN022503), dated February 26, 2025.
- 4. NRC (Dennis Galvin) electronic correspondence to Entergy (Riley Keele, Jr.),
"Arkansas Nuclear 1 - Request for Additional Information - Request for Review and Approval Changes to SAR and to a Confirmatory Order - PZR HTR Emergency Power Supply (EPID L-2024-LLA-0092,"(ADAMS Accession No. ML25079A328), (1CNA032502), dated March 19, 2025.
cc:
NRC Region IV Regional Administrator NRC Senior Resident Inspector - Arkansas Nuclear One NRC Project Manager - Arkansas Nuclear One Designated Arkansas State Official Digitally signed by Philip Couture DN: cn=Philip Couture, o=Entergy, ou=Regulatory Assurance, email=pcoutur@entergy.com Date: 2025.04.08 10:57:12 -04'00' Philip Couture
ENCLOSURE 1CAN042501 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION
1CAN042501 Enclosure Page 1 of 5 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION
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Background===
By application dated July 2, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession Number ML24184B775), as supplemented by letter dated February 26, 2025 (ML25057A318), Entergy Operations, Inc. (Entergy, the licensee) requested an amendment to the Renewed Facility Operating License Number DPR-51 for Arkansas Nuclear One, Unit 1 (ANO-1). The proposed changes would modify the ANO-1 Safety Analysis Report (SAR) and the January 2, 1980, Confirmatory Order (ML021220215) to allow an alternate means of compliance with the post TMI-2 recommendation that any changeover of the pressurizer heaters from normal offsite power to emergency onsite power is to be accomplished manually in the control room. The proposed changes would allow for certain loss of offsite power (LOOP) events the performance of manual actions at 120 VAC instrument panels Y01 and Y02 outside the control room to restore power to the pressurizer low-low level interlock to allow operation of required pressurizer heaters on emergency onsite power.
Regulatory BasisSection IV of the Confirmatory Order ordered in part.
The Licensee by January 31, 1980, implement all "Category A" requirements referred to in Part II of this Order,Section II of the Confirmatory Order referred to requirements in three documents:
NUREG-0578, "TMI-2 Lessons Learned Task Force Status Report and Short-term Recommendations", dated July 1979 (ML090060030), which sets forth measures identified by the NRC TMI-2 Lessons Learned Task Force to be taken in the short-term to reduce the likelihood of accidents and to improve emergency preparedness in responding to accidents. Section 2.1.1 of NUREG-0578 provides recommendations regarding pressurizer heaters.
Generic Letter 79-40, "Followup Actions Resulting from the NRC Staff Reviews Regarding the Three Mile Island Unit 2 Accident," dated September 13, 1979 (ML112990325), which transmitted to licensees "Category A" requirements, which were actions at operating nuclear power plants that require prompt implementation to provide continued assurance of public health and safety. Specifically, Enclosure 6 of Generic Letter 79-40, designates the recommendations in Section 2.1.1 of NUREG-0578 as Implementation Category A, with an implementation completion date of January 1, 1980.
Generic Letter 79-56, "Discussion of Lessons Learned Short Term Requirements,"
dated October 30, 1979 (ML031320403), which provided clarifications to the requirements in NUREG-0578. Specifically, Section 2.1.1 of the enclosure to Generic Letter 79-56 identified four positions and seven clarifications regarding pressurizer heaters. The fourth clarification states:
1CAN042501 Enclosure Page 2 of 5
- 4. Any change-over of the heaters from normal offsite power to emergency onsite power is to be accomplished manually in the control room.
NUREG-0737, "Clarification of TMI Action Plan Requirements," dated November 1980 (ML102560051), identifies all post-TMI requirements which had been approved for implementation by the Commission at that time. Most of the items in NUREG-0737 had been previously issued as requirements as prior correspondence, though some new requirements were issued in NUREG-0737. NUREG-0737, Item II.E.3.1, "Emergency power for pressurizer heaters," is the designation for the requirements in Section 2.1.1 of NUREG-0578. The requirements in NUREG-0737, Item II.E.3.1 are unchanged from the clarification of Section 2.1.1 of Generic Letter 79-56, including the fourth clarification item.
The staff used the guidelines in Section 2.7.8, "Relaxation, Withdrawal, or Rescission of Orders", of Part I, "Enforcement Process," of the Enforcement Manual, (https://www.nrc.gov/about-nrc/regulatory/enforcement/guidance.html#manual) to review the licensees request to modify the Confirmatory Order. Section 2.7.8 states that the NRC staff may relax, withdraw, or rescind conditions of an order and provides criteria that should be considered when evaluating the licensees good cause justification.
Issue:
The licensee requests in part to modify requirements imposed by the January 2, 1980, confirmatory order, specifically the TMI requirements that any change-over of the pressurizer heaters from normal offsite power to emergency onsite power is to be accomplished manually in the control room. In 2015, the licensee identified that during certain loss of offsite power (LOOP) events, power would be lost to the pressurizer low-low level heater interlock. If the interlock is de-energized, the required heaters cannot be operated. The design of ANO-1 requires manual operator actions outside the control room to restore power to the pressurizer low-low level heater interlock to allow the operation of the minimum TS required pressurizer heaters. Thus, the change-over of the pressurizer heaters from normal offsite power to emergency onsite power cannot be accomplished from the control room for all LOOP events.
Therefore, the licensee is requesting a modification of the confirmatory order to allow an alternative to the TMI requirements. The NRC staff has identified questions with (a) the confirmatory order requirements the licensee is proposing to change and (b) the justification for the change.
Question 1:
- a. The licensee proposes to make changes to the January 2, 1980, Confirmatory Order with a proposed change to NUREG-0737 Item II.3.E.1. As noted in the regulatory basis, NUREG- 0737 is not referenced in the confirmatory order as the confirmatory order was issued prior to NUREG-0737. Therefore, the licensee is not requesting an actual change to the confirmatory order. The licensee is requested to describe a proposed change to a document incorporated into the confirmatory order, including clearly describing the relationship of the document to the order and the specific ordered language.
1CAN042501 Enclosure Page 3 of 5
Response
Based on the guidance in NRC's Enforcement Manual Section 2.7.8 (Reference 1), Entergy requests a partial withdrawal of the requirements of the confirmatory order issued to ANO 1 on January 2, 1980 (Reference 2). The confirmatory order requires that ANO-1 implement all "Category A" lessons learned requirements from NUREG-0578. The requirements for Pressurizer Heater Power Supply are specified in NUREG-0578, Section 2.1.1.
Generic Letter 79-40, "Followup Actions Resulting from the NRC Staff Reviews Regarding the Three Mile Island Unit 2 Accident," dated September 13, 1979 (Reference 3), transmitted to licensees "Category A" requirements. These actions were issued to operating nuclear power plants that required prompt implementation to provide continued assurance of public health and safety. Enclosure 6 of Reference 3 designated the recommendations in Section 2.1.1 of NUREG-0578 as "Implementation Category A", with an implementation completion date of January 1, 1980.
Generic Letter 79-56, "Discussion of Lessons Learned Short Term Requirements," dated October 30, 1979 (Reference 4), provided clarifications to the requirements in NUREG-0578.
Section 2.1.1 of Enclosure 1 to Reference 4 identified several positions and clarifications regarding pressurizer heaters. The fourth clarification states:
- 4. Any change-over of the heaters from normal offsite power to emergency onsite power is to be accomplished manually in the control room.
Entergy proposes that the Reference 2 Confirmatory Order requiring all "Category A" short-term recommendations from NUREG-0578 be implemented with the following exception to Item 2.1.1, "Emergency Power Supply Requirements for the Pressurizer Heaters, Power-Operated Relief Valves and Block Valves, and Pressurizer Level Indicators in PWRs."
Reference 4 Emergency Power Supplies Clarification 4 text is updated as follows:
Any changeover of the heaters from normal offsite power to emergency onsite power is to be accomplished manually in the control room. Upon failure of Green-train electrical power, changeover includes actions performed locally at 120 VAC instrument panels Y01 and Y02 to restore power to the Pressurizer Low-Low Level Interlock. This action is outside the control room.
Proposed revision is underlined.
This change will be incorporated into the ANO-1 SAR as discussed in Reference 5.
- b. The process for a licensee to request a relaxation, withdrawal, or rescission of a requirement in an order is described in Section 2.7.8 of the Enforcement Manual. The licensee request does not provide a specific good cause justification for its request or otherwise address the guidance in Section 2.7.8 of the Enforcement Manual. The licensee is requested to provide a specific good cause justification consistent with Section 2.7.8 of the Enforcement Manual for the proposed change to the confirmatory
1CAN042501 Enclosure Page 4 of 5 order. This justification may refer to the justification for the proposed change to the ANO-1 SAR.
Response
NRC Enforcement Manual Section 2.7.8 specifies that a licensee can show that "good cause" exists when the action continues to provide reasonable assurance of adequate protection. In this instance Entergy meets the "good cause" requirement by proposing an alternate means to align pressurizer heaters that does not reduce the effectiveness intended by the order.
The purpose of NUREG-0578 item 2.1.1 is to promptly supply emergency "power to the pressurizer heaters to maintain subcooling during natural circulation conditions following a LOOP. For most LOOP scenarios, ANO-1 can align emergency power from the control room as required by Reference 2. However, Entergy is proposing an alternate means to align emergency power to the pressurizer heaters for a single limited scenario outside the control room - the failure of the green train powered low-low level heater interlock. Application of the manual action outside the control room, does not reduce the assurance of public health and safety when compared to actions within control room.
In the July 2, 2024, request (Reference 5), Entergy documented that:
The manual action outside the control room does not delay pressurizer heater initiation when compared to the action in the control room. Entergy committed to provide emergency power to the pressurizer heaters within 2-hours. The manual actions outside the control room have an average completion time between 30-45 minutes.
The manual actions are achievable under the proposed conditions. The actions outside the control room meet all the requirements for crediting manual operator actions specified in Information Notice 97-78 (Reference 6).
Following the manual action, the pressurizer heaters function the same as when aligned within the control room.
The manual actions outside the control room are already contained in plant procedures and the operators are trained on the use of these procedures.
The continued compliance with this partially withdrawn order will be accomplished through an update to the ANO-1 SAR and the plant time critical action program.
Given the limited LOOP scenario where the manual action would be required and documented ability to perform the manual actions, the proposed partial withdrawal of the Reference 2 Confirmatory Order combined with the manual actions provides adequate protection and meets the "good cause requirements of Reference1.
1CAN042501 Enclosure Page 5 of 5 References
- 1. "Nuclear Regulatory Commission Enforcement Manual," Parts I and II, (ADAMS Accession Number ML20329A339), Revision 11.7.
- 2. NRC letter to now Entergy Operations, Inc. (Entergy), "Confirmatory Order, Order Confirms Your Commitment as Stated in Your Letters to Implement All Category a Lessons Learned Requirements Prior to Plant Operations After 1/31/80," (ADAMS Accession Number ML021220215), (1CNA018003), dated January 2, 1980.
- 3. NRC Generic Letter 79-40, "Followup Actions Resulting from the NRC Staff Reviews Regarding the Three Mile Island Unit 2 Accident," (ADAMS Accession Number ML112990325), (0CNA097915), dated September 13, 1979.
- 4. NRC Generic Letter 79-56, "Discussion of Lessons Learned Short Term Requirements,"
(ADAMS Accession Number ML031320403), (0CNA117903), dated October 30, 1979.
- 5. Entergy letter to NRC, "Request for Review and Approval of Changes to the Safety Analysis Report and to a Confirmatory Order Clarifying an Alternate Means of Compliance for Pressurizer Heaters Emergency Power Supply," (ADAMS Accession Number ML24184B775), (1CAN072401), dated July 2, 2024.
- 6. NRC Information Notice 97-78, "Crediting Operator Actions in Place of Automatic Actions and Modifications of Operator Actions, Including Response Times," (ADAMS Accession Number ML031050065), dated October 23, 1997.