NL-24-0321, License Amendment Request to Change Technical Specification 3.6.5, Containment Air Temperature Actions - Supplemental Information
| ML24229A245 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 08/16/2024 |
| From: | Coleman J Southern Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| Shared Package | |
| ML24229A243 | List: |
| References | |
| NL-24-0321 | |
| Download: ML24229A245 (1) | |
Text
J!. Southern Nuclear Regulatory Affairs 3535 Colonnade Parkway Birmingham, AL 35243 205 992 5000 WITHHOLD FROM PUBLIC DISCLOSURE UNDER 10 CFR 2.390.
(DECONTROLLED UPON REMOVAL OF ENCLOSURE 4)
August 16, 2024 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant Units 1 and 2 Docket Nos. 50-348 and 50-364 NL-24-0321 10 CFR 50.90
Subject:
License Amendment Request to Change Technical Specification 3.6.5, "Containment Air Temperature" Actions - Supplemental Information On July 18, 2024, Southern Nuclear Operating Company (SNC) requested a license amendment to the Technical Specifications (TS) for Joseph M. Farley Nuclear Plant (FNP),
Units 1 and 2 renewed facility operating licenses NPF-2 and NPF-8, respectively (ADAMS Accession No. ML24201A108). The requested amendment would revise the operating license, Appendix A, Technical Specification (TS) 3.6.5, Containment Air Temperature, Actions upon exceeding the containment average air temperature limit and remove an expired Limiting Condition for Operation Note. On July 31, 2024, the NRC Staff conducted an audit of the supporting calculations and identified that additional information was necessary to be submitted on the docket. The identified additional information is provided in the Enclosures.
SNC continues to request expedited review and approval of the proposed license amendment by August 29, 2024. This license amendment will be implemented promptly upon issuance.
SNC's response to supplemental information items 5 and 6 is provided as Enclosure 1. An affidavit and request for withholding proprietary information is provided as Enclosure 2. A non-proprietary version of the supplemental information items 1, 2, 3, 4 and 7 is provided as and a proprietary version of the supplemental information items 1, 2, 3, 4 and 7 is provided as Enclosure 4.
The additional information provided in Enclosures 1, 3 and 4 to this letter does not impact the regulatory evaluation (including the Significant Hazards Consideration Determination) or environmental considerations for the proposed changes provided in the July 18, 2024, submittal. contains information proprietary to Westinghouse Electric Company LLC
("Westinghouse"), and it is supported by an Affidavit signed by Westinghouse, the owner of the information (Enclosure 2). The Affidavit sets forth the basis on which the information may be
U. S. Nuclear Regulatory Commission NL-24-0321 Page 2 withheld from public disclosure by the Nuclear Regulatory Commission ("Commission") and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.390 of the Commission's regulations. Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR 2.390 of the Commission's regulations.
Correspondence with respect to the copyright, proprietary aspects, or the supporting Westinghouse Affidavit should reference CAW-24-041 and should be addressed to Zachary S.
Harper, Senior Manager, Licensing Engineering.
This letter contains no regulatory commitments. This letter has been reviewed and determined not to contain security-related information.
In accordance with 10 CFR 50.91, SNC is notifying the State of Alabama of this license amendment request by transmitting a copy of this letter, enclosure, and attachments to the designated State Official.
If you have any questions, please contact Ryan Joyce at 205-992-6468.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on the 16th day of August 2024.
Respectfully submitted,
' ~
~n Director, Regulatory Affairs Southern Nuclear Operating Company JMC/was/cbg :
Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 :
Westinghouse Electric Company Affidavit and Request for Withholding Proprietary Information :
Supplemental Information Items 1, 2, 3, 4 and 7 - Non-Proprietary :
Supplemental Information Items 1, 2, 3, 4 and 7 - Proprietary cc:
NRC Regional Administrator, Region II NRR Project Manager - Farley 1 & 2 Senior Resident Inspector - Farley 1 & 2 Alabama - State Health Officer for the Department of Public Health RType: CFA04.054
License Amendment Request to Change Technical Specification 3.6.5, "Containment Air Temperature" Actions - Supplemental Information Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 Supplemental information items 5 and 6 are repeated below and followed by the Southern Nuclear Operating Company (SNC) response.
Supplemental Information Item 5:
Based on the revised mass and energy release corresponding to an accumulator temperature of 124°F using the NRC-approved WCAP-10325-P-A methodology, for the limiting double-ended pump suction break with the most limiting single failure, using a bounding containment initial temperature of 127°F, provide the following:
(a). Changes in the GOTHIC model used for containment pressure, temperature, and sump temperature responses.
(b). Results of peak pressure, peak temperature, peak sump temperature, and maximum recirculation sump temperature including comparison of these parameters with those in the analysis of record.
(c). Result graphs of containment pressure, temperature, and sump temperature responses.
(d). Results showing available net positive suction head (NPSH), required NPSH, and NPSH margins for the residual heat removal (RHR) and containment spray (CS) pumps.
SNC Supplemental Information for Item 5:
(a). Changes in the GOTHIC model used for containment pressure, temperature, and sump temperature responses.
The following changes were made to the containment response model previously reviewed and approved by the NRC in ML22263A225:
Mass and energy releases - GOTHIC table functions associated with break flow and break enthalpy were revised with updated mass and energy release data corresponding to accumulator temperatures at 124 °F.
Inactive metal energies - GOTHIC table functions associated with inactive metal energies for the upper head, the pressurizer, and the steam generators were revised with updated values provided by Westinghouse in conjunction with the updated mass and energy releases.
Updated time to start recirculation - Added a trip to account for RHR interruption following recirculation signal. This delays recirculation by 180 seconds as compared to the analysis of record. The change was made to accurately reflect the plant operating procedures and has an insignificant impact on the results.
Control Variables - Three control variables were added to the model in order to collect data not readily available in the GOTHIC code output data. These control variables are used only to process outputs and do not impact the calculated results.
E-1 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 (b). Results of peak pressure, peak temperature, peak sump temperature, and maximum recirculation sump temperature including comparison of these parameters with those in the analysis of record.
Tables 1 and 2 provide the requested information and comparison.
Table 1:
Comparison of the Bounding DEPS_MinESF Case at 124°F to the AOR DEPS_MinESF Case Bounding DEPS_MinESF Case AOR DEPS_MinESF at 124°F Case Difference Maximum Pressure 45.02 psig 44.83 psig
+0.19psi Maximum Vapor Temp 264.64°F 264.36°F
+0.28°F Maximum Sump Temp 259.00°F 258.66°F
+0.34°F Table 2:
Maximum Calculated Sump Temperature During Recirculation Maximum Recirc Sump Temperature 251.35°F = 251 °F Time 2320.9 s E-2 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 (c). Result graphs of containment pressure, temperature, and sump temperature responses.
Figures 1, 2 and 3 provide the requested graphs.
- 01) so 45 40 35 "vi 30 c..
~- 25
~
~ 20 a..
15 10 5
0 0.001 Containment Pressure Response 0.1 10 1000 100000 10000000 Time, s Figure 1: Containment Pressure Response E-3
--TS124F _DEPS_MinESF to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 280 260 240
- u. 220 a,'
- , 200
~
~ 180 E
Q)
I-
- u.
160 140 120 100 0.001 300 280 260 240
~- 220
~ 200 Q)
C.
E 180 Q) 1-160 140 120 100 0.001 Containment Vapor Temperature Response
--TS124F _DEPS_MinESF 0.1 10 1000 100000 10000000 Time, s Figure 2: Containment Vapor Temperature Response Containment Sump Temperature Response 0.1 10 1000 Time, s
--TS124F _DEPS_MinESF
-- MinESF Recirculation Time 100000 10000000 Figure 3: Containment Sump Temperature Response E-4 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 (d). Results showing available net positive suction head (NPSH), required NPSH, and NPSH margins for the residual heat removal (RHR) and containment spray (CS) pumps.
Net Positive Suction Head (NPSH) margin for the Residual Heat Removal (RHR) and Containment Spray (CS) pumps during the LOCA recirculation phase are provided in the tables provided below.
NPSH available (NPSHA), required (NPSHR) and the NPSH margin are detailed below at sump temperatures between 120°F and 292.4°F for the RHR and CS pumps.
Unit 1 - A Train Containment Spray NPSH Margin Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin (OF)
Elevation (ft)
Elevation (ft)
(ft) 120 110 80.375 46.3 18 28.3 140 (-)
110 80.375 43.9 18 25.9 140 (+)
110 80.375 45.0 18 27.0 160 110 80.375 40.8 18 22.8 180 110 80.375 34.4 18 16.4 206.6 110 80.375 20.9 18 2.9 206.6*
110 80.375 20.8 18 2.8 212*
110 80.375 20.8 18 2.8 291*
110 80.375 20.8 18 2.8 292.4*
110 80.375 20.8 18 2.8
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F U *t 1 BT. C t.
m ram on ammen ts pray NPSH M argm Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin
(°F)
Elevation (ft)
Elevation (ft)
(ft) 120 110 80.375 40.7 18 22.7 140 (-)
110 80.375 39.2 18 21.2 140 (+)
110 80.375 45.3 18 27.3 160 110 80.375 41.1 18 23.1 180 110 80.375 34.7 18 16.7 206.6 110 80.375 21.2 18 3.2 206.6*
110 80.375 21.2 18 3.2 212*
110 80.375 21.2 18 3.2 291*
110 80.375 21.2 18 3.2 292.4*
110 80.375 21.2 18 3.2
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F E-5 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 U *t 2 AT. C t.
m ram on ammen ts ipray NPSHM argm Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin (OF)
Elevation (ft)
Elevation (ft)
(ft) 120 110 80.375 46.1 18 28.1 140 (-)
110 80.375 43.7 18 25.7 140 (+)
110 80.375 44.8 18 26.8 160 110 80.375 40.6 18 22.6 180 110 80.375 34.2 18 16.2 206.6 110 80.375 20.7 18 2.7 206.6*
110 80.375 20.7 18 2.7 212*
110 80.375 20.7 18 2.7 291*
110 80.375 20.7 18 2.7 292.4*
110 80.375 20.7 18 2.7
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F Unit 2 - B Train Containment Spray NPSH Margin Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin (OF)
Elevation (ft)
Elevation (ft)
(ft) 120 110 80.375 39.3 18 21.3 140 (-)
110 80.375 37.8 18 19.8 140 (+)
110 80.375 43.2 18 25.2 160 110 80.375 39.0 18 21.0 180 110 80.375 32.6 18 14.6 206.6 110 80.375 19.1 18 1.1 206.6*
110 80.375 19.1 18 1.1 212*
110 80.375 19.1 18 1.1 291*
110 80.375 19.1 18 1.1 292.4*
110 80.375 19.1 18 1.1
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F E-6 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 U. 1 AT. R "d
I H R
mt -
ram esI ua eat emova IP ump NPSH M argm Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin
(°F)
Elevation (ft)
Elevation (ft)
(ft) 120 110 81.625 46.1 18 28.1 140 (-)
110 81.625 43.8 18 25.8 140 (+)
110 81.625 44.8 18 26.8 160 110 81.625 40.6 18 22.6 180 110 81.625 34.2 18 16.2 206.6 110 81.625 20.7 18 2.7 206.6*
110 81.625 20.7 18 2.7 212*
110 81.625 20.7 18 2.7 291*
110 81.625 20.7 18 2.7 292.4*
110 81.625 20.7 18 2.7
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F U. 1 BT. R "d
I H R
mt -
ram esI ua eat emova IP ump NPSH M argm Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin (OF)
Elevation (ft)
Elevation (ft)
(ft) 120 110 81.625 45.0 18 27.0 140 (-)
110 81.625 42.7 18 24.7 140 (+)
110 81.625 43.7 18 25.7 160 110 81.625 39.5 18 21.5 180 110 81.625 33.1 18 15.1 206.6 110 81.625 19.6 18 1.6 206.6*
110 81.625 19.6 18 1.6 212*
110 81.625 19.6 18 1.6 291*
110 81.625 19.6 18 1.6 292.4*
110 81.625 19.6 18 1.6
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F E-7 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 U *t 2 AT. R "d
I H t R m
ram es1 ua ea emova IP ump NPSH M argm Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin (OF)
Elevation (ft)
Elevation (ft)
(ft) 120 110 81.625 44.6 18 26.6 140 (-)
110 81.625 42.2 18 24.2 140 (+)
110 81.625 43.3 18 25.3 160 110 81.625 39.1 18 21.1 180 110 81.625 32.7 18 14.7 206.6 110 81.625 19.2 18 1.2 206.6*
110 81.625 19.2 18 1.2 212*
110 81.625 19.2 18 1.2 291*
110 81.625 19.2 18 1.2 292.4*
110 81.625 19.2 18 1.2
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F Unit 2 - B Train Residual Heat Removal Pump NPSH Margin Temperature Sump Pump NPSHA (ft)
NPSHR (ft)
NPSH Margin (OF)
Elevation (ft)
Elevation (ft)
(ft) 120 110 81.625 44.7 18 26.7 140 (-)
110 81.625 42.4 18 24.4 140 (+)
110 81.625 43.4 18 25.4 160 110 81.625 39.2 18 21.2 180 110 81.625 32.8 18 14.8 206.6 110 81.625 19.3 18 1.3 206.6*
110 81.625 19.3 18 1.3 212*
110 81.625 19.3 18 1.3 291*
110 81.625 19.3 18 1.3 292.4*
110 81.625 19.3 18 1.3
- Containment pressure = Vapor Pressure of sump inventory
(-) includes head loss due to aluminum particulate.
(+) head loss due to aluminum-based particulate is negligible for temperatures greater than 140°F GOTHIC is not used for calculation of NPSH in the Analysis of Record (AOR). The maximum peak containment pressure following a LOCA serves as an input to the NPSH calculation. The equation for NPSH available used is a summation of the energies (pressures and/or static heights, frictional flow resistances, fluid vapor phase limitations) that assist in or detract from the pressure at the pump's inlet. These parameters are containment pressure, sump fluid vapor pressure, elevation of sump fluid level, elevation of pump, and frictional flow resistance through the sump screens and pump suction piping.
The equation for NPSHA is as follows:
144 NPSHA = -(Pctm -
P vapor) + h sump -
hpump -
h1oss p
E-8 to NL-24-0321 Evaluation of the Proposed Change - Supplemental Information Items 5 and 6 Supplemental Information Item 6:
In the LAR enclosure, refer to the following statement under the heading, "Net Positive Suction Head (NPSH) Evaluation,"
"The strainer head losses are also shown to decrease as the sump temperature increases above 140°F. Based on the competing effects between vapor pressure of the sump inventory and strainer head losses, the pump NPSH margin would be expected to increase or stay the same as the sump temperature increases above 212°F."
Provide a basis and results of the strainer head losses decrease as the temperature increases above 140°F.
SNC Supplemental Information for Item 6:
Table 1 below summarizes the total strainer head loss for temperatures at 120°F, 140°F, 160°F, 180°F and 212°F as documented in the associated containment sump passive residual heat removal (RHR) and containment spray (CS) strainer hydraulic sizing report. The NPSH is calculated at each of these corresponding temperatures, and additionally includes the intermediate temperature of 206.6°F. The strainer head loss corresponding to 206.6°F is interpolated between 180°F and 212°F. An additional sump fluid temperature is evaluated which is the saturation temperature corresponding to the maximum containment pressure following a LOCA. This temperature has no corresponding strainer head loss value in the associated report but is assigned a value. The bounding high-end temperature of 292.4°F for the sump fluid temperature is the saturation temperature corresponding to the maximum containment peak pressure of 45 psig / 59.7 psia. Since this temperature is above the highest temperature (212°F) provided below, the strainer head loss is conservatively taken to be the same as that corresponding to 212°F. This approach is conservative because it can be seen from the table that as the sump fluid temperature increases, the head loss across the strainer decreases.
Table 1: Head Loss vs. Temperature (inches of water) 120°F 140°F 140°F 160°F 180°F 212°F et::
A Train 46.05 41.92 29.49 29.24 29.07 28.8
- c et::
B Train 59.13 54.97 42.54 42.26 42.08 41.78
~
C:
A Train 39.31 35.93 22.81 22.54 22.35 22.16 en u B Train 106.36 92.15 18.9 18.46 18.13 17.74 et::
A Train 49.11 44.97 32.54 32.28 32.1 31.83
- c N
et::
B Train 47.81 43.67 31.24 30.98 30.81 30.54
~
C:
A Train 41.54 38.15 25.03 24.75 24.55 24.36 en u B Train 123.26 109.27 44.39 43.95 43.68 43.37 E-9
License Amendment Request to Change Technical Specification 3.6.5, "Containment Air Temperature" Actions - Supplemental Information Westinghouse Electric Company Affidavit and Request for Withholding Proprietary Information
Commonwealth of Pennsylvania:
County of Butler:
Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-24-041 (1)
I, Zachary Harper, Senior Manager, Licensing, have been specifically delegated and authorized to apply for withholding and execute this Affidavit on behalf of Westinghouse Electric Company LLC (Westinghouse).
(2)
I am requesting the proprietary portions ofNL-24-0321, Revision 0 be withheld from public disclosure under l 0 CFR 2.390.
(3)
I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged, or as confidential commercial or financial information.
Page 1 of3 (4)
Pursuant to 10 CFR 2.390, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.
(i)
The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse and is not customarily disclosed to the public.
(ii)
The information sought to be withheld is being transmitted to the Commission in confidence and, to Westinghouse's knowledge, is not available in public sources.
(iii)
Westinghouse notes that a showing of substantial harm is no longer an applicable criterion for analyzing whether a document should be withheld from public disclosure. Nevertheless, public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar technical evaluation justifications and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.
- This record was final approved on 08/16/2024 16:11 :48. (This statement was added by the PRIME system upon its validation)
Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-24-041 (5)
Westinghouse has policies in place to identify proprietary information. Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:
(a)
The information reveals the distinguishing aspects of a process ( or component, structure, tool, method, etc.) where prevention of its use by any of Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies.
Page 2 of3 (b)
It consists of supporting data, including test data, relative to a process ( or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage (e.g., by optimization or improved marketability).
( c)
Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product.
( d)
It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.
(e)
It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.
(f)
It contains patentable ideas, for which patent protection may be desirable.
(6)
The attached documents are bracketed and marked to indicate the bases for withholding. The justification for withholding is indicated in both versions by means of lower-case letters (a) through (f) located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These lower-case letters refer to the types of information Westinghouse customarily holds in confidence identified in Sections (5)(a) through (f) of this Affidavit.
- This record was final approved on 08/16/2024 16:11 :48. (This statement was added by the PRIME system upon its validation)
Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-24-041 I declare that the averments of fact set forth in this Affidavit are true and correct to the best of my knowledge, information, and belief. I declare under penalty of perjury that the foregoing is true and correct.
Executed on: 8/16/2024 Signed electronically by Zachary Harper Page 3 of3
- This record was final approved on 08/16/2024 16:11 :48. (This statement was added by the PRIME system upon its validation)
License Amendment Request to Change Technical Specification 3.6.5, "Containment Air Temperature" Actions - Supplemental Information Supplemental Information Items 1, 2, 3, 4 and 7 - Non-Proprietary
Westinghouse Non-Proprietary Class 3 Supplemental Information Item 1 Part A to ALAM-LOCA-1M-LR-000003, Revision 0 Page 2 of36 As discussed in the recently submitted Southern Nuclear Company (SNC) Licensing Amendment Request (LAR) to change the Technical Specification 3.6.5, "Containment Air Temperature" Actions (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24201A107, Reference 1 ), Farley Nuclear Plant Units 1 and 2 (FNP) received approval to implement the Automated Statistical Treatment of Uncertainty Method (ASTRUM) Evaluation Model (EM) (Reference 2) by Amendment No. 174 (ADAMS Accession No. ML061810306, Reference 3). The ASTRUM evaluation model relies on a statistical sampling technique to demonstrate that there is a high level of probability that the 10 CFR 50.46 acceptance criteria would not be exceeded under postulated large-break loss-of-coolant accident (LBLOCA) conditions. The statistical sampling of the uncertainty contributors occurs simultaneously in the uncertainty analysis, leading to scatter in the analysis results when plotted as a function of a single uncertainty contributor. As such, execution of the ASTRUM evaluation model framework was not considered to be the best option to estimate the effect of the maximum accumulator temperature (TACC) increase from 120°F to 122°F.
Since the change under consideration is small relative to the range of accumulator temperatures analyzed in the FNP ASTRUM analysis (90 to 120°F versus 90 to 122°F; see Figure 1-1 ), existing accumulator temperature sensitivities performed with the same thermal-hydraulic code used in the FNP ASTRUM analysis from similar pressurized water reactor (PWR) plant designs with similar fuel assembly design, power level, and predicted cladding temperature response were utilized to determine an estimated effect to support the requested change. Westinghouse considers it a best practice not to execute the WCOBRA/TRAC system thermal-hydraulic code for small changes to the inputs that are expected to lead a change in the predicted results within the resolution of the code.
In addition, the FNP fuel thermal conductivity degradation (TCD) evaluation approach was part of a Pressurized Water Reactor Owner's Group (PWROG) program to estimate the effect of fuel TCD for plants as part of a second 'wave' of fuel TCD evaluations. The PWROG approach utilized
[
]a,c considered plant-specific core design and fuel rod design data, plant-specific WCOBRA/TRAC runs that modeled fuel TCD were not executed for FNP. Further, estimates of effects for errors/changes on the FNP analysis downstream of fuel TCD (which are outlined in more detail in Supplemental Information Item 4 ), did not include plant-specific WCOBRA/TRAC executions. As such, the relatively small change to the design input parameters and the lack of recent plant-specific WCOBRA/TRAC executions led to the chosen evaluation approach.
- This record was final approved on 08/16/2024 16:11 :48. (This statement was added by the PRIME system upon its validation)
Part B Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-1M-LR-000003, Revision 0 Page 3 of36 Based on the timing of the analyses, the code versions utilized, and the evaluation approach described in Supplemental Information Item 2, errors/changes to the WCOBRA/TRAC code reported to the NRC as part of 10 CFR 50.46 yearly reporting that could affect the estimate of effect are reviewed. The yearly reports of interest were sent to the NRC in L TR-NRC-02-10, (Reference 5) and L TR-NRC-03-05 (Reference 6). The reporting text for each error/change provides background and a description of the estimated effect.
In the provided yearly reports, only the following affected evaluation models are relevant, 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM In other words, errors/changes to the Appendix Kand SECY UPI evaluation models are not relevant for this review. The errors/changes applicable to the best-estimate LOCA evaluation models are reviewed at a high level to aid in the NRC staff review. Note that general code maintenance reporting is not reviewed.
LTR-NRC-02-10 -Westinghouse 10 CFR 50.46 reporting for 2001 ENHANCEMENTS TO MONTE CARLO PCT - Not Applicable to WCOBRA/TRAC (N/A)
RESPONSE SURFACE PLOT TITLE ERROR - NIA OXIDATION THICKNESS INDEX ERROR FOR BEST ESTIMATE WCOBRA/TRAC-applicable to WCOBRA/TRAC, no effect for standard BELOCA analyses NEUTRON/CS CALCULATION MODERATOR DENSITY WEIGHTING FACTOR ERROR
- applicable to WCOBRA/TRAC, effect of error correction estimated to be 0°F LTR-NRC-03 Westinghouse 10 CFR 50.46 reporting for 2002 RESPONSE SURFACE MATRIX OPERATION AND RANDOM SEARCH ERRORS - N/A BROKEN COLD LEG MODELING DEVIATIONS-NIA 1-0 MINIMUM FILM BOILING TEMPERATURE MODEL SELECTION ERROR-applicable, effect of error correction estimated to be 0°F 1-0 CONDENSATION RAMP ERROR - applicable to WCOBRA/TRAC, effect of error correction estimated to be 0°F CLADDING AXIAL THERMAL EXPANSION ERROR - applicable to WCOBRA/TRAC, effect of error correction estimated to be 0°F ERROR IN TIME AFTER SHUTDOWN FOR NEUTRON CAPTURE TERM - applicable to WCOBRA/TRAC, effect of error correction estimated to be 0°F
- This record was final approved on 08/16/2024 16:11 :48. (This statement was added by the PRIME system upon its validation)
Part C Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-1M-LR-000003, Revision 0 Page 4 of36 USER CONVENIENCES IN HOTSPOT - NIA POTENTIAL DIVIDE BY ZERO ERROR DURING PUMP ROTATION REVERSAL - NIA, not applicable to design basis analyses APPLICATION OF DECAY HEAT UNCERTAINTY TO PROMPT FISSION ENERGY ERROR - NIA, not applicable to design basis analyses BYPASS OF ORIFICE ENTRAINMENT MODEL IN DOWNFLOW WITH CHANNEL SPLITTING - NIA, not applicable to design basis analyses The requested comparison is provided in Table 1-1. The plant similarity comparison performed as part of the evaluation also considered the predicted PCT response (as described in the LAR (Reference 1)). Figures 1-8 through 1-10 provide the PCT transients utilized.
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 5 of36 Table 1-1 Plant Operating Range Allowed by the Best-Estimate Large-Break LOCA Analyses for FNP, Plant A, and Plant B Parameter Operating Range FNP Plant A Plant B 1.0 Plant Physical Description a)
Hot assembly location Anywhere in core Anywhere in core Anywhere in core b) Fuel assembly / Hot assembly type 17 x I 7, ZIRLO cladding I 7 x I 7, ZIRLO cladding I 7 x I 7, ZIRLO cladding c)
Steam generator tube plugging level
- 'S 10%
- 'S 10%
- 'S 22%
2.0 Plant Initial Operating Conditions 2.1 Reactor Power a) Core average linear heat rate Core power :'S 102% of2775 Core power :'S I 02 % of 2900 Core power :'S I 00.6 % of 2900 MWt MWt MWt b) Total core peaking factor FQ:'S 2.5 FQ:'S 2.5 FQ :'S 2.52 c) Hot channel enthalpy rise peaking FL'>H :'S 1.7 FL'>H :'S 1.7 FL'>H :'S 1.75 factor d) Hot assembly enthalpy rise peaking PHA :'S 1.7/1.04 PHA :'S 1.7/1.04 PHA :'S 1.75/1.04 factor e) Hot assembly peak linear heat rate FQ,HA :'S 2.5/1.04 FQ,HA :'S 2.5/1.04 FQ,HA :'S 2.52/1.04 2.2 Fluid Conditions a) TAvo 567.2 +/- 6°F :'S TAvG :'S 577.2 +/- 6°F 572.0 +/- 5.3°F :'S TAvG :'S 587.4 +/-
566.2 +/- 4°F :'S TAvG :'S 580.0 +/- 4°F 5.3°F b) Pressurizer pressure PRcs = 2250 psia +/- 50 psi PRcs = 2250 psia + I 00 psi PRcs = 2250 psia +/- 50 psi c) Loop flow 2: 86,000 gpm/loop 2: 92,600 gpm/loop 2: 87,200 gpm/loop d) Accumulator temperature 90°F :'S T ACC :'S 120°F 85°F :'S TAcC :'S l 15°F 70°F :'S TAcc :'S 105°F e) Accumulator pressure 600 psia :'S P Ace :'S 680 psia 585 psia :'S P Ace :'S 70 I psia 575 psia :'S PAcc :'S 716 psia
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Table 1-1 Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 6 of36 Plant Operating Range Allowed by the Best-Estimate Large-Break LOCA Analyses for FNP, Plant A, and Plant B Parameter Operating Range FNP Plant A Plant B f) Accumulator volume (tank only) 965 ft3 :S V ACC :S 995 ft3 994 ft3 :S V ACC :S 1034 ft3 922 ft3 :S V ACC :S 1072 ft3 3.0 Accident Boundary Conditions a) Offsite power Available or LOOP Available or LOOP Available or LOOP b) Safety injection flow Figure 1-2 (Reference DEG case)
Figure 1-3 (Reference DEG case)
Figure 1-4 (Reference DEG case) c) Safety injection temperature 70°F :S T SI :S 100°F 55°F :S Ts1 :S 95°F 45°F :S T SI :S 105°F d) Safety injection delay
- S 12 seconds (with offsite power)
- S 22 seconds (with offsite power)
- S 17 seconds (with offsite power)
- S 27 seconds (without offsite
- S 32 seconds (without offsite
- S 27 seconds (without offsite power) power) power) e) Containment pressure Bounded - Figure 1-5 Bounded - Figure 1-6 Bounded - Figure 1-7 f) Single failure Loss of one ECCS train Loss of one ECCS train Loss of one ECCS train
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 7 of36 Figure 1-1: Illustration of Effect of Updated Accumulator Temperature Range on the ASTRUM Uncertainty Analysis Input
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 8 of36 Intact Loop 1
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 9 of36 I TA CT LOOP SI MASS FLOW RA TE 200 ---------------------------------,
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Figure 1-3: Safety Injection Flow from Plant A Reference DEG Transient
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en E
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 10 of36 INTAC T LO OP 1 SI MASS FLO W RATE r,
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Figure 1-4: Safety Injection Flow from Plant B Reference DEG Transient
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40 35 20 15 Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 11 of36 10 -+...... _.__...__.__,,.......__..._............. __....... _._........ _____ -"' ___....... _ __. ___.__.._...._"r'-__ _._...... _...-1 0
50 100 150 Time (s) 200 2
Figure 1-5: Containment Backpressure from FNP ASTRUM Analysis 300
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 12 of36 40 ~-----------------------------~
35 0
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Figure 1-6: Containment Backpressure from Plant A CQD Analysis
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 13 of36 45,------- - - ----- - ------ - - --
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Figure 1-7: Containment Backpressure from Plant B CQD Analysis
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I-Westinghouse Non-Proprietary Class 3 L i m itin g Cos e (R o n k 1) to ALAM-LOCA-TM-LR-000003, Revision 0 Page 14 of36
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I 400 500 Figure 1-8: HOTSPOT Clad Temperature at the PCT Location for the Top Ten PCT Limiting Cases from the FNP ASTRUM Analysis
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 15 of36 Figure 1-9: PCT Comparison from Accumulator Water Temperature Parametric Study from Plant A
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 16 of36 a,c Figure 1-10: PCT Comparison from Accumulator Water Temperature Parametric Study from Plant B Supplemental Information Item 2
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Supplemental Information Item 2 Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 17 of36 The existing CQD methodology initial condition sensitivities [
Based on the review of the accumulator temperature sensitivity studies performed using the CQD methodology for similar plant designs, fuel types and power levels, the 2°F increase in the maximum accumulator temperature is estimated to have a 2°F effect on the analysis PCT based on the biased trend lines and times-2 multiplier to account for temperature effects of the FNP rackup items.
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 18 of36 Table 2-1: Plant A and Plant B Accumulator Temperature Sensitivities Figure 2-1: Plant A Accumulator Temperature Sensitivity
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 19 of36 Figure 2-2: Plant B Accumulator Temperature Sensitivity Figure 2-3: Plant B Accumulator Temperature Sensitivity Data with Conservatively Biased Trend Line
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Supplemental Information Item 3 Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 20 of36 Westinghouse would first like to acknowledge the process by which the originally identified pool of potential applicable accumulator temperature sensitivity studies was reduced to determine a reasonable estimate of effect for FNP. FNP Units 1 and 2 are Westinghouse-designed 3-loop PWRs with a 17x17 fuel assembly array and power level of over 2,700 MWth (see Table 1-1 ). Similar Westinghouse-designed plants with similar fuel assembly designs and power levels and a former CQD methodology analysis were reviewed to identify potentially relevant parametric accumulator temperature sensitivities. The FNP predicted temperature response (shown in Figure 1-8) is characterized by blowdown PCT on the order of 1400-to-1500°F, a refill PCT slightly higher than the blowdown PCT, and a reflood PCT on the order of 200-300°F higher occurring roughly 100 seconds into the transient. Figure 1-9 and Figure 1-10 show that the Plant A and Plant B temperature transients are very similar, while [
As noted in the LAR (Reference 1 ), the 18 accumulator temperature studies were surveyed as a confirmation of the magnitude of impact of a change in accumulator temperature on PCT. It was acknowledged that the plants surveyed included variations in the number of RCS loops, fuel assembly design, power level, and peaking factors. It should further be acknowledged that the 18 sensitivity studies are based on 11 WCOBRA/TRAC PWR models. Table 3-1 reflects the information shared during the in-person audit.
[
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 21 of36 Table 3-1: Accumulator Temperature Sensitivity Results
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 22 of36 Figure 3-1: PCT Comparison from Accumulator Water Temperature Parametric Study from Plant C
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Supplemental Information Item 4 The Plant B sensitivity study used to [
1 Local thermal-hydraulics refers to [
]a,c Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 23 of36
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. [
Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 24 of36 2 The post-TCD estimate of effect for the error in HTM distributions was based [
]a,c
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[
Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 25 of36
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[
Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 26 of36 Ja,c
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[
Summary Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 27 of36 The intent of the performed evaluation was to provide an estimate of effect pursuant to 10 CFR 50.46(a)(3) for a change in the maximum accumulator temperature. The regulation requires an estimate of effect of any change to or error in an acceptable evaluation model or in the application of such a model to determine if the change or error is significant. While no requirement in the regulation exists relative to the conservatism or bounding nature of the estimate of effect, it is understood that the estimate must be reasonable such that NRC staff can ensure the continued validity of the LOCA analysis and downstream rackup items for the purpose of demonstrating compliance with the 10 CFR 50.46 regulatory acceptance criteria. Based on the performed evaluation and additional justification, it has been demonstrated that a [
]a,c As such, the 2°F increase in the maximum accumulator temperature is estimated to have a 14°F effect on the FNP analysis PCT.
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(.)
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Westinghouse Non-Proprietary Class 3 Top of Core
Middle of Core
* Bottom of Core to ALAM-LOCA-TM-LR-000003, Revision 0 Page 28 of36 30000....--------------------------------
20000 10000 0 li I
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 29 of36 a,c Figure 4-2: Lower Plenum Collapsed Liquid Level Predicted in Limiting DEG Transients from the FNP ASTRUM Analysis
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 30 of36 Figure 4-3: Lower Plenum Liquid Subcooling Predicted in Limiting DEG Transients from the FNP ASTRUM Analysis
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 31 of36 Figure 4-4: Hot Rod PCT Predicted in Limiting DEG Transients from the FNP ASTRUM Analysis
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 32 of36 Figure 4-5: Illustration of Effect of Temperature Transients on Predicted Metal-Water Reaction
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 33 of36 Figure 4-6: Illustration of Heat Generation Rate from Decay Heat and Metal-Water Reaction
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 34 of36 Supplemental Information Item 7 The Farley Units 1 and 2 small break loss-of-coolant accident (SBLOCA) analysis of record is licensed with the NOTRUMP evaluation model (NOTRUMP EM) in compliance with 10 CFR 50 Appendix K. The containment response is not explicitly modeled in the NOTRUMP EM due to the elevated pressures in the RCS during a SBLOCA. The pressure difference across the break will remain high enough for the flow rate to be governed by critical flow relationships such that the containment conditions do not impact the rate of RCS mass loss. However, maximum containment temperature is commonly used as an input to the NOTRUMP EM SBLOCA analysis to define the accumulator water temperature in the model. For a SBLOCA transient event, the primary challenge facing the emergency core cooling system (ECCS) is delivering sufficient flow to maintain or recover RCS level against the backpressure within the system. For 3-Loop plants it is relatively common for the accumulators to play a vital role in maintaining inventory for an intermediate pressure range between the initial gas cover pressure and the low head safety injection cut-in pressure.
Table 7-1 summarizes the SBLOCA peak cladding temperature (PCT), PCT time, and accumulator injection time information presented in Tables 15.3-2A and 15.3-2B of the Final Safety Analysis Report (FSAR) for Farley Units 1 and 2 (Reference 7). Note that all reported cases were performed at the high-end reactor coolant system (RCS) average temperature (Tavg) operating range and the results apply to the full operating range.
Table 7-1: Farley Units 1 and 2 FSAR Summary of Small Break LOCA Results Break Size PCT (°F)
PCT Time (s)
Accumulator Injection (Cold Leg Break)
Time (s) 2-inch 985.7 3184.4 n/a 2.25-inch 1455.1 2177.3 2524 2.5-inch 1570.6 1906.3 1880 2.75-inch 1903.61 1642.51 1375 3.0-inch 1834.61 1326.61 1119 3.25-inch 1702.1 1180.7 973 4.0-inch 1456.7 755.7 616 6.0-inch 1035.0 334.0 270 Notes:
- 1.
The results presented are for the limiting time-in-life at 10,000 MWd/MTU burnup.
Based on the transient summary data in Table 7-1, the RCS depressurization for the 2-inch break does not actuate the accumulators; therefore, this break is not impacted by the containment temperature increase. For the remaining breaks, the accumulator injected mass contributes to the recovery of the core, and in most cases the accumulators actuate prior to the mixture level reaching its minimum elevation corresponding to the PCT time. It is noted that the PCT occurs over 250 seconds after accumulator injection for the limiting break size (2.75-inch) and over 200 seconds after accumulator injection for the next highest PCT (3.0-inch break). Any potential impact on the accumulator injection timing due to the containment temperature change (discussed further below) would have minimal effect for the limiting cases by the time the PCT occurs. Furthermore, the smallest difference between accumulator injection time and PCT time occurs for the 2.5-inch break. In this case, the PCT is over 300°F lower than the limiting PCT, such that any impact of the containment temperature increase on the accumulator timing would not cause this break size to become limiting.
The NOTRUMP Evaluation Model (EM) does not [
]a,c The timing of the initial injection is important because typically the accumulators deliver
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Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 35 of36 a relatively large initial water volume relatively quickly and taper off to a lower, more steady flow rate as the RCS continues to slowly depressurize. However, the initial injection behavior and timing observed in NOTRUMP EM analyses would not be expected to change due to the increased containment temperature.
From a transient perspective, the water injected to the RCS via the accumulators is first heated from its subcooled initial state to the local saturated liquid conditions (sensible heat transfer). Additional heat added to the injected fluid eventually vaporizes a portion (latent heat transfer). The higher initial accumulator water enthalpy from an increased containment temperature would be expected to reduce the amount of energy on a per unit mass basis that the accumulator water can absorb; however, the latent heat of vaporization and associated energy removal capability would be expected to remain unchanged.
For the sub-cooled ECCS water supplied by the accumulators, an increase in containment temperature from 120°F to 124°F corresponds to an enthalpy increase of ~4 Btu/lbm. The change in sensible heat removal from the RCS associated with a 4 Btu/lbm initial enthalpy change would remain small relative to both the total sensible heat capacity of the accumulator fluid and the latent heat capacity. Additionally, small break LOCA transients are characterized as relatively slow-moving top-down draining of the RCS with marked periods of flow stratification.
Stored energy is typically not of concern for SBLOCA transients as there is adequate time, RCS flow, and heat sink capability (via the steam generators and the break) to remove stored energy from the fuel and vessel internals prior to core uncovery.
Based on the relatively small reduction in total energy removal capability of the accumulator fluid associated with a 124 °F initial containment temperature, accumulator initial injection timing and characteristics remaining unaffected, and the low core and vessel internals stored energy associated with a small break transient, it was concluded that increasing the maximum containment temperature at Farley Units 1 and 2 from 120°F to 124°F will have a negligible impact on the small break LOCA analysis of record.
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Reference(s)
Westinghouse Non-Proprietary Class 3 to ALAM-LOCA-TM-LR-000003, Revision 0 Page 36 of36
- 1. Letter from Jamie M. Coleman (SNC) to NRC Document Control Desk, "License Amendment Request to Change Technical Specification 3.6.5, 'Containment Air Temperature' Actions," July 2024. (Available in NRC ADAMS under Accession Number ML24201A107 (Proprietary) and ML24201A108 (Non-Proprietary))
- 2. Westinghouse Report WCAP-16009-P-A, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment Of Uncertainty Method (ASTRUM)," January 2005. (Westinghouse Proprietary Class 2)
- 3. Letter from Robert E. Martin (NRC) to L. M. Stinson (SNC), "JOSEPH M. FARLEY NUCLEAR PLANT, UNITS 1 AND 2 -
ISSUANCE OF AMENDMENTS FOR BEST ESTIMATE LOSS-OF-COOLANT ACCIDENT (LOCA) ANALYSES USING ASTRUM (TAC NOS. MC8588 AND MC8589)," July 2006.
(Available in NRC ADAMS under Accession Number ML061810306)
- 4. Westinghouse Report WCAP-12945-P-A, Volume 1, Revision 2 and Volumes 2 through 5, Revision 1, "Code Qualification Document for Best Estimate LOCAAnalysis," March 1998. (Westinghouse Proprietary Class 2)
- 5. Letter from H. A. Sepp (Westinghouse) to J. S. Wermiel (NRC), "U.S. Nuclear Regulatory Commission 10 CFR 50.46 Annual Notification and Reporting for 2001," March 2002.
- 6. Letter from H. A. Sepp (Westinghouse) to J. S. Wermiel (NRC), "U.S. Nuclear Regulatory Commission 10 CFR 50.46 Annual Notification and Reporting for 2002," March 2003.
- 7. Joseph M. Farley Nuclear Plant Unit 1 and Unit 2 Final Safety Analysis Report Update, Revision 30.
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