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Category:E-Mail
MONTHYEARML23331A8922023-11-22022 November 2023 Supplement - Braidwood Security Rule Exemption Request ISFSI Docket No. Reference ML23317A2012023-11-22022 November 2023 (External_Sender) Supplement - Byron Security Rule Exemption Request ISFSI Docket No. Reference ML23321A2012023-11-17017 November 2023 NRR E-mail Capture - Constellation Energy Generation, LLC - Fleet Request - Acceptance of Proposed Alternative for Examination of Pressurizer Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Vessel Welds (L-2023-LLR-0062) ML23311A1692023-11-0707 November 2023 NRR E-mail Capture - Constellation - Fleet Request - Acceptance of Proposed Alternative for Examinations of Exam Categories B-B, B-D, and C-A SG Pressure Retaining Welds and Full Penetration Welded Nozzles (L-2023-LLR-0055 and L-2023-LLR-00 ML23311A1682023-11-0707 November 2023 NRR E-mail Capture - Constellation - Fleet Request - Acceptance of Proposed Alternative for Examinations of Examination Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections (L-2023-LLR-0053 and L-2023-LLR-005 ML23305A2992023-11-0101 November 2023 NRR E-mail Capture - NRC Acceptance Review of Byron, Unit 2, Relief Request I4R-24 ML23304A0222023-10-30030 October 2023 NRR E-mail Capture - Final RCI - Constellation Energy Generation, LLC - Braidwood 1 & 2 - Exemption from Security Rule (L-2023-LLE-0030) ML23304A0202023-10-30030 October 2023 NRR E-mail Capture - Final RCI - Constellation Energy Generation, LLC - Byron 1 & 2 - Exemption from Security Rule (L-2023-LLE-0027) ML23272A0602023-09-29029 September 2023 NRR E-mail Capture - NRC Acceptance Review of Byron, Unit 1, Relief Request I4R-25 ML23187A0092023-07-0606 July 2023 NRR E-mail Capture - NRC Acceptance Review of Byron and Braidwood Request to Adopt TSTF-370 ML23103A4692023-04-12012 April 2023 NRR E-mail Capture - NRC Acceptance Review of Braidwood Request for Amendment to Revise TS 3.7.9 ML23069A0332023-03-0606 March 2023 Email to K. Lueshen Byron and Braidwood Commitment 10 - Request for Additional Information Set 1 ML23115A2412023-01-20020 January 2023 NRR E-mail Capture - Preliminary RAIs Related to L-2022-LLA-0131 - Byron, Unit 2, Reinsertion of an Accident Tolerant Fuel Lead Test Assembly ML22354A2622022-12-20020 December 2022 NRR E-mail Capture - Constellation Energy Generation, LLC - Fleet Request - Acceptance of Request to Use Certain Provisions of the 2019 Edition of the ASME BPV Code, Section XI ML22284A1022022-10-0606 October 2022 NRR E-mail Capture - NRC Acceptance Review for Byron, Unit 2, License Amendment Request (LAR) to Reinsert an Accident Tolerant Fuel (ATF) Lead Test Assembly (LTA) (L-2022-LLA-0131) NRC-2100-2022, EN 55999 Valcor Coil Shell Assemblies Final Notification (004)2022-09-12012 September 2022 EN 55999 Valcor Coil Shell Assemblies Final Notification (004) ML22255A0132022-09-0909 September 2022 NRR E-mail Capture - NRC Acceptance Review of Braidwood, Byron, Calvert Cliffs, Ginna - License Amendment Request to Adopt TSTF-577 ML22200A0782022-07-19019 July 2022 NRR E-mail Capture - Constellation Energy Generation, LLC - Fleet Request to Use Honeywell Mururoa V4F1 R Supplied Air Suits NRC 2110-2022, EN 55999 - Valcor Engineering Corporation (009)2022-07-18018 July 2022 EN 55999 - Valcor Engineering Corporation (009) ML22189A0602022-07-0707 July 2022 NRR E-mail Capture - Draft RAI for Byron/Braidwood TSTF-501 ML22136A2722022-05-16016 May 2022 NRR E-mail Capture - NRC Acceptance Review of Braidwood and Byron Adoption of TSTF-501 ML22129A0132022-05-0606 May 2022 NRR E-mail Capture - Draft RAIs for Requests for Alternatives I4R-17, I4R-23, ISI-05-018, I6R-10 ML22271A0772022-05-0606 May 2022 NRR E-mail Capture - Final RAIs 9.1.2021 Constellation Relief Request ML22116A0242022-04-25025 April 2022 NRR E-mail Capture - NRC Acceptance Review of Braidwood, Byron, and Ginna Request to Adopt TSTF-246 ML22105A0722022-04-15015 April 2022 NRR E-mail Capture - Braidwood/Byron Verbal Authorization for Proposed Alternative I4R-15/I4R-21 ML22091A0852022-04-0101 April 2022 NRR E-mail Capture - Braidwood and Byron - Final RAI Regarding Proposed Alternative for Various Pressurizer Welds (EPID L-2021-LLR-0035 and 0036) ML22088A1562022-03-0202 March 2022 NRR E-mail Capture - Byron, Braidwood, Calvert Cliffs, and Ginna - Non-acceptance of Application to Revise Technical Specifications 5.6.5.b, the Core Operating Limits Report (COLR) ML22091A0842022-02-24024 February 2022 NRR E-mail Capture - Braidwood and Byron - Withdrawal of Draft RAI Regarding Proposed Alternative for Various Pressurizer Welds (EPID L-2021-LLR-0035 and 0036) ML22041B5362022-02-10010 February 2022 NRR E-mail Capture - Constellation Energy Generation, LLC - Request for Additional Information Regarding Fleet License Amendment Request to Adopt TSTF-541 ML23089A0152022-01-0505 January 2022 NRR E-mail Capture - NRC Acceptance Review of Byron - Proposed Alternative for Examinations of Categories B-B, B-D, and C-A SG Welds and Nozzles ML23089A0172022-01-0505 January 2022 NRR E-mail Capture - NRC Acceptance Review of Braidwood - Proposed Alternative for Examinations of Categories B-B, B-D, and C-A SG Welds and Nozzles ML21301A0672021-10-28028 October 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Acceptance of License Amendment Request to Adopt TSTF-541 ML21272A1492021-09-29029 September 2021 NRR E-mail Capture - NRC Acceptance Review of Braidwood and Byron - Proposed Alternative for Examinations of Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections ML21256A1902021-09-10010 September 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding License Transfer Application ML21252A0172021-09-0303 September 2021 NRR E-mail Capture - NRC Acceptance Review - Braidwood - License Amendment to Revise Technical Specification 3.7.9, Ultimate Heat Sink ML21252A0042021-08-26026 August 2021 NRR E-mail Capture - NRC Acceptance Review - Braidwood/Byron/Clinton - Adoption of TSTF-273, Safety Function Determination Program Clarifications ML21215A3502021-08-0303 August 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Acceptance of License Amendment Request to Adopt TSTF-554 ML21203A3112021-07-21021 July 2021 NRR E-mail Capture - Final Byron Permanently Defueled Technical Specifications (PDTS) - Second Round RAI ML21189A1602021-07-0808 July 2021 NRR E-mail Capture - Request for Additional Information - Braidwood, Byron, and Ginna - Amendment to Address the Issues in Westinghouse NSALs ML21189A1612021-07-0808 July 2021 NRR E-mail Capture - Second Round Request for Additional Information - Byron Permanently Defueled Technical Specification Amendment ML21154A0162021-06-0202 June 2021 NRR E-mail Capture - NRC Acceptance Review of Braidwood - Proposed Alternative for Exam of Pzr Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Shell Welds ML21154A0172021-06-0202 June 2021 NRR E-mail Capture - Acceptance Review of Byron - Proposed Alternative for Exam of Pzr Circumferential and Longitudinal Shell-to-Head Welds and Nozzle-to-Shell Welds ML21154A0132021-05-28028 May 2021 NRR E-mail Capture - Extension of Comment Period for the Exelon Generation Company, LLC License Transfer Application ML21154A0112021-05-28028 May 2021 NRR E-mail Capture - Extension of Comment Period for the Exelon Generation Company, LLC License Transfer Application ML21154A0142021-05-28028 May 2021 NRR E-mail Capture - Extension of Comment Period for the Exelon Generation Company, LLC License Transfer Application ML21144A2132021-05-24024 May 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Request for Additional Information Regarding License Transfer Application ML21123A2442021-05-0303 May 2021 NRR E-mail Capture - NRC Acceptance Review of Braidwood/Byron/Ginna - Application to Address the Issues Identified in Westinghouse Documents NSAL-09-5 and NSAL-15-1 (L-2021-LLA-0066) ML21117A0442021-04-26026 April 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Proposed Fleet Alternative to Documentation Requirements for Pressure Retaining Bolting ML21084A2532021-03-24024 March 2021 NRR E-mail Capture - Exelon Generation Company, LLC - Acceptance of License Transfer Application ML21081A0972021-03-19019 March 2021 Acceptance Review for Byron Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis-External Events (EPID L-2021-JLD-0004) (E-mail) 2023-09-29
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Text
From: Samuel Miranda To: Corujo-Sandin, Jorge
Subject:
[External_Sender] Design Bases Assurance Inspection at the Byron and Braidwood units Date: Friday, November 23, 2018 3:58:55 PM
Dear Mr. Corujo-Sandin,
Please consider my comments, regarding your upcoming Design Bases Assurance Inspection at the Byron and Braidwood units. I understand that the Design Bases Assurance Inspection focuses on the
"design, maintenance, and operation of risk significant components - associated with an accident
scenario, or a specific system. The inspection also monitors the implementation of modifications to
structures, systems, and components."
Please look at the Byron and Braidwood licensing basis [1], and think about how the accident analysis assumes how the plants' pressurizer safety valves (PSVs) will operate. The PSVs are designed
to open at the RCS design pressure (2500 psia), and relieve enough steam to prevent the RCS
pressure from rising above 110% of its design pressure (2750 psia). Any accident that can pressurize
the RCS its design pressure, post-reactor trip, would have to be a Condition III or IV event. PSVs are
designed to open and limit this pressurization. They are not required to close. The analyses in the
Byron and Braidwood licensing basis [1] contain several important changes, or deviations from this
design requirement:(1)The PSVs are assumed to open, during an AOO, in order to prevent the AOO from developing into a Condition III or IV event. (This is an acceptance criterion for AOO events.) The assumption makes
no sense, since by the time the PSVs can open (at 2500 psia), the AOO will have already developed
into a Condition III or IV event.
(2)The PSVs are now required to close, in order to prevent the progression to a Condition III or IV event (e.g., a stuck-open PSV). This is a new design requirement for the PSVs.
(3)The PSVs are now required to relieve water, as well as steam. This is a new design requirement for the PSVs. Crosby, the firm that manufactures these valves, intends these valves to be used only
for steam relief.(4)The PSVs are now required to open and close, repeatedly; as necessary, and relieve water, as well as steam, without incurring any damage. It appears that Exelon intends to operate the PSVs as
PORVs.(5)GDC 21 requires that, redundancy and independence designed into the protection system shall be sufficient to assure that - no single failure results in loss of the protection function. The new
requirement (i.e., PSV closure) makes it impossible to comply with GDC 21.
The failure of one PSV to close would create a Condition III LOCA at the top of the pressurizer (i.e., a single failure would cause
the loss of the protection function). In other words, if the GDC 21 single failure assumption is
applied, the required protection function (i.e., closure of all PSVs) cannot be accomplished when all
the valves are connected in parallel. Consider, too, that the PSVs are not isolable. The PSV system
can meet the GDC 21 single failure requirement when the PSVs are required to open; but not when
they're required to close.
In October, 2015, NRR issued a backfit order, regarding the Byron and Braidwood plants, which
included, among other things, this issue of PSV closure requirements, and the application of GDC 21.
[2]Exelon appealed the backfit [3] directly to the EDO. Upon receiving the appeal, the EDO
appointed a panel of five to review Exelon's appeal, and make the recommendations necessary to
support his appeal decision. [4]
(Note that one member of this panel was K. Stephen West.
)The EDO's decision [5] deems Exelon's PSVs to be absolutely reliable (i.e., infallible) components, insofar as they can be trusted to open and close, without fail, even when they're operated beyond their design capabilities (i.e., under water relief duty). In order to do this, the EDO set aside GDC 21.
In other words, GDC 21 no longer applies to the PSVs at the Byron and Braidwood plants.
The EDO's backfit appeal decision recognizes the PSVs, at Exelon's Byron and Braidwood plants, as PSVs that are capable of relieving water. Have you seen a design review and modification package, from Exelon that justifies the use of PSVs, under water relief duty, in the Byron and Braidwood licensing basis? [1] If not, would it be reasonable to request this information, as part of your Design Bases Assurance Inspection?
Samuel Miranda, PE REFERENCES
[1] Final Safety Analysis Report, Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2, Chapter 15.5.1, Inadvertent Operation of Emergency Core Cooling System During Power Operation (ADAMS No. ML14363A495)
[2] USNRC, Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2 -Backfit Imposition Regarding Compliance with 10 CFR 50.34(b), GDC 15, GDC 21, GDC 29, and Licensing Basis, October 9, 2015 (ADAMS No. ML14225A871)
[3] Exelon Generation Company, LLC, letter from J. Bradley Fewell to Victor M. McCree, U.S. NRC,"Appeal of Imposition of Backfit Regarding Compliance with 10 CFR § 50.34(b), General Design Criteria (GDC) 15, GDC 21, GDC 29, and Licensing Basis," dated June 2, 2016 (ADAMS Accession No.
ML16154A254)
[4] USNRC, Report of the Backfit Appeal Review Panel Chartered by the Executive Director for Operations to Evaluate the June 2016 Exelon Backfit Appeal, Gary M. Holahan (OEDO), Thomas G.
Scarbrough (NRO), Michael A. Spencer (OGC), Theresa V. Clark (OEDO), K. Steven West (NSIR), August 23, 2016, (ADAMS No. ML16236A208)
[5] Result of Appeal to the Executive Director for Operations of Backfit Imposed on Byron and Braidwood Stations Regarding Compliance with 10 CFR 50.34(b), GDC 15, GDC 21, GDC 29, and the Licensing Basis, USNRC, September 15, 2016, (ADAMS Nos. ML16246A247, ML16236A202, ML16246A247, ML16243A067, ML16246A150, and ML16236A208)
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