ML26057A107

Nuclear Fuel Services, Inc. - Biannual Effluent Monitoring Report July to December 2025

ML26057A107
Person / Time
Site:	Erwin
Issue date:	02/16/2026
From:	Rogers D Nuclear Fuel Services
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards
References
21G-26-0042, GOV-01-55, ACF-26-0061
Download: ML26057A107 (0)

Text

Nuclear Fuel Services, Inc.

Certified Mail Return Receipt Requested Director Office of Nuclear Material Safety & Safeguards U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

Reference:

Docket No.70-143; SNM License 124 21 G-26-0042 GOV-01-55 ACF-26-0061 February 16, 2026

Subject:

Biannual Effluent Monitoring Report July to December 2025

Dear Director:

In accordance with the requirements set forth in 10 CFR Part 70.59, Nuclear Fuel Services, Inc. (NFS), submits the attached reports. Attachment 1 reports the Radioactivity in Effluent Liquid for the period July to December 2025. Attachment 2 reports the Radioactivity in Effluent Air for the period July to December 2025. Attachment 3 summarizes an evaluation of the dose and air activity concentrations for the maximally exposed offsite individual due to gaseous effluents during the period July to December 2025.

If you or your staff have any questions, require additional information, or wish to discuss this, please contact me at (423) 735-5475, or Mr. Brian W. McAllister, Environmental Safety Unit Manager, at (423) 735-5450. Please reference our unique document identification number (21 G-26-0042) in any correspondence concerning this letter.

Sincerely, NUCLEAR FUEL SERVICES, INC.

~:?~

Safety & Safeguards Director CJB/las Attachments

1) Report of Radioactivity in Effluent Liquid for the Period July to December 2025

2) Report of Radioactivity in Effluent Air for the Period July to December 2025

3) Report of Gaseous Effluent Dose and Activity Concentrations for the Maximally Exposed Off-Site Individual for the Release Period July to December 2025 People Strong INNOVATION DRIVEN >

1205 Banner Hill Rd, Erwin, TN 37650 t: +1.423.743.9141 I: +1.423.743.0140 www.nuclearfuelservic~~e 1 Of 14

Copy:

Mr. Nicholas Peterka Senior Fuel Facility Inspector U. S. Nuclear Regulatory Commission Region II 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 Regional Administrator U. S. Nuclear Regulatory Commission Region II 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 Mr. James Downs Senior Project Manager Division of Fuel Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Two White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 Bradley Davis Chief, Projects Branch 1 U.S. Nuclear Regulatory Commission Region II 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 Mr. Richard Skokowski Senior Resident Inspector U. S. Nuclear Regulatory Commission Page 2 of 14 21 G-26-0042 GOV-01-55 ACF-26-0061 To Letter Dated February 16, 2026 Report of Radioactivity in Effluent Liquid for the Period July to December 2025 (2 Pages to Follow)

Page 3 of 14 21 G-26-0042 GOV-01-55 ACF-26-0061

Radioactivity in Effluent Liquid July 1, 2025 to December 31, 2025 Total Activity Error Quantity Volume Concentration Estimate LLD Released Location (I)

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci)

Banner Spring Down Pu-238 291,916,000 O.OOE+OO 8.77E-11 2.24E-10 O.OOE+OO Pu-239/240 291,916,000 5 49E-12 9.98E-ll 2.38E-l 0 J.60E-06 Tc-99 291,916,000 5.35E-09 3.58E-08 6.27E-08 I.56E-03 Th-228 291,916,000 4.69E-1 I l.52E-10 2.95E-10 1.37E-05 Th-230 291,916,000 4.52E-11 l.73E-10 3.41E-10 I.32E-05 Th-232 29 I,916,000 3.58E-12 l.05E-10 2.23E-IO l.OSE-06 U-233/234 291,916,000 2 47E-IO 2.20E-IO 2.79E-10 7.22E-05 U-235/236 291,916,000 4.85E-l l l.06E-IO l.78E-l 0 l.42E-05 U-238 291,916,000 7.35E-ll l.36E-10

2. !OE-I 0

2. l SE-05 Sewer Pu-238 28,345,075 2.96E-ll 1.0IE-10 2 02E-IO 8.39E-07 Pu-239/240 28,345,075 O.OOE+OO 9.32E-l l 2.41E-IO O.OOE+OO Tc-99 28,345,075 I.OSE-08 3.46E-08 6.00E-08 3.07E-04 Th-228 28,345,075 O.OOE+OO 1.75E-10 3.85E-10 O.OOE+OO Th-230 28,345,075 l.09E-10 2.l7E-10 3.72E-IO 3.08E-06 Th-232 28,345,075 O.OOE+OO l.1 4E-IO 2.52E-10 O.OOE+OO U-232 28,345,075 4.88E-11 I 42E-IO 2.62E-I 0 I.38E-06 U-233/234 28,345,075

8. 13E-09 7.27E-10 l.58E-I 0 2.30E-04 U-235/236 28,345,075 3.63E-IO l.60E-10 I.I 7E-10 l.03E-05 U-238 28,345,075 l.07E-09 2.65E-10 l.3IE-IO 3.03E-05 West Ditch Pu-238 73,009,000 O.OOE+OO 8.00E-11 1.94E-l 0 OOOE+OO Pu-239/240 73,009,000 O.OOE+oO 9.84E-l l 2.48E-IO O.OOE+OO Tc-99 73,009,000 0 OOE+OO 3.42E-08 6.11 E-08 O.OOE+OO Th-228 73,009,000 4.00E-11 l.84E-l0 3.49E-IO 2.92E-06 Th-230 73,009,000 4.73E-11 l.81E-IO 3.SSE-10 3.45E-06 Th-232 73,009,000 2.57E-1 I 1.07E-I 0 2.0SE-10 I.88E-06 U-233/234 73,009,000 l.3!E-08 l.28E-09 2.75E-10 9.58E-04 U-235/236 73,009,000 6.12E-10 3.2IE-IO l.84E-IO 4.47E-05 U-238 73,009,000 8.49E-IO 3.38E*l0 2.20E-10 6.20E-05 WWTF Am-241 3,731,737 5.l6E-l I l.60E-IO 3.03E-10 1.92E-07 Cs-137 3,731,737 2.38E-IO 1.19E-09 l.94E-09 8.88E-07 Na-22 3,731,737 O.OOE+OO 1.12E-09 I.SOE-09 0.00E+OO Np-237 3,731,737 2.27E-l l 2.SIE-10 5.33E-10 8.49E-08 Pb-212 3,731,737 l.47E-10 3.84E-09 4.29E-09 5.48E-07 Pu-238 3,731,737 3.95E-12 l.23E-I 0 2.69E-IO l.47E-08 ECV: EffluBnl ConcenlraUon Value from 10-CFR-20, Appendix 8 Nole: A value of *o* was substltuled for negative analytical results.

Printed: 02/04/2026 NFS* EDMS Page 4 of 14 Quantity Released (g)

O.OOE+OO 2.58E-05 9.24E-02 l.67E-08 6 54E-04 9.60E+OO 1.16E-02 6.56E+OO 6.41E+OI Total:

4.91E-08 O.OOE+OO 1.82E-02 O.OOE+OO l.53E-04 O.OOE+OO 6.47E-08 3.69E-02 4 77E+OO 9.03E+Ol Total:

O.OOE+OO O.OOE+OO O.OOE+OO 3.57E-09 l.7IE-04 1.72E+OI 1.54E-OI 2.07E+Ol l.85E+02 Total:

5.61E-08 I.02E-08 O.OOE+OO l.21E-04 3.97E-13 8.61E-IO 21 G-26-0042 GOV-01-55 ACF-26-0061 Fraction or 1

ECV O.OOE+OO 2.75E-04 8.9JE-05 2.34E-04 4.52E-04 l.19E-04 8.24E-04 I 62E-04 2.45E-04 2.40E-03 l.48E-04 O.OOE+OO I.SOE-OS 0.00E+OO I.09E-04 O.OOE+OO 8.14E-05 2.?IE-03 l.21E-04 3.56E-04 3.S4E-03 O.OOE+OO O.OOE+OO O.OOE+OO 2.00E-04 4.73E-04 8.58E-04 4.37E-02 2.04E-03 2.83E-03 5.0lE-02 2.58E-03 2.38E-04 O.OOE+OO I. 14E-03 7.35E-05 l.97E-04 Page I of2

Radioactivity in Effluent Liquid July 1, 2025 to December 31, 2025 Total Activity Volume Concentration Location (I)

(µCi/ml)

WWTF Pu-239/240 3,731,737 l.97E-ll Pu-241 3,731,737 0.00E+OO Tc-99 3,731,737 0.00E+OO Th-228 3,731,737 4.3 IE-11 Th-230 3,731,737 l.21E-10 Th-231 3,731,737 O.OOE+OO Th-232 3,731,737 1.16E-12 U-232 3,731,737 O.OOE+OO U-233/234 3,731,737 9.44E-09 U-235/236 3,731,737 4.74E-10 U-238 3,731,737 l.06E-10 ECV* Effluent Concenlr1ti0n Value lrom 1O-CFR*2O, Appendix B.

Nole: A value or *o* was substituted ror negallve analytical results Printed: 02/04/2026 Error Qu~ntlty Estimate LLD Released

(µCi/ml)

(µCi/ml)

(Ci) l.42E-10 2.93E-10 7.35E-08 l.38E-08 2.43£-08 O.OOE+OO 8.l9E-08 1.44E-07 O.OOE+OO l.88E-10 3.54E-10 l.61E-07 2.17E-10 3.B IE-10 4.52E-07 4.0SE-08 5.BOE-08 O.OOE+OO 1.33E-10 2.74E-10 4.3 IE-09 2.03E-10 4.62E-10 O.OOE+OO 9.45E-10 2.37E-10 3.52E-05 2.23E-10 l.6SE-10 I. 77E-06 l.25E-10 l.SBE-10 3.97E-07 NFS-EDMS Page 5 of 14 Quantity Released (g) 1.IBE-06 O.OOE+OO O.OOE t*OO 1.96£- 10 2.24E-05 O.OOE+OO 3.96E-02 O.OOE+OO 5.64E-03 8.18E-01 l.19E+OO Total:

21 G-26-0042 GOV-01-55 ACF-26-0061 Fraction of ECV 1

9.85E-04 O.OOE+OO O.OOE+OO 2.1 SE-04 1.21E-03 O.OOE+OO 3.85E-05 O.OOE+OO 3.1 SE-02 l.58E-03 3.SSE-04 4.0lE-02 Page 2 of2 To Letter Dated February 16, 2026 Report of Radioactivity in Effluent Air for the Period July to December 2025 (3 Pages to Follow)

Page 6 of 14 21 G-26-0042 GOV-01-55 ACF-26-0061

Total Volume Location (m')

Main Stack 416 Th-228 266,830,738 Th-230 266,830,738 Th-232 266,830,738 U-234 266,830,738 U-235 266,830,738 U-238 266,830,738 Stack 327 Bldg. 330 Pu-241 250,307,788 Tc-99 250,307,788 U-234 250,307,788 U-235 250,307,788 Stack 421 Bldg. 100 Pu-241 9,043,401 Tc-99 9,043,40 I U-234 9,043,401 U-235 9,043,401 Stack 424 Bldg. 100 Pu-241 7,797,767 Tc-99 7,797,767 U-234 7,797,767 U-235 7,797,767 Stack S73 Bldg 306-W Pu-241 29,637,820 Tc-99 29,637,820 U-234 29,637,820 U-235 29,637,820 Stack 600 Bldg. 110 Pu-241 77,151,627 Tc-99 77,151,627 U-234 77,151,627 U-235 77,151,627 Stack 615 Bldg. 306-W Pu-241 14,097,822 Radioactivity in Effluent Air July 1, 2025 to December 31, 2025 Activity Error Quantity Concentration Estimate LLD Released

(µ.Ci/ml)

(µCi/ml)

(µCi/ml)

(Ci) 1007.06 m '!min 16.78 m 3/sec 1.0IE*l5 l.81E*l6 8.48E-l 7 2.68E*07 l.OIE-15 J.81E-16 8.48E-l 7 2.68E-07 7.SSE-16 l.36E-16 6.36E-17 2.0IE-07 2.37E-13 4.26E-14 2.00E-14 6.33E-05 9.06E-15 l.63E-15 7.63E-16 2.42E-06 2.52E-l 5 4.S2E-16 2.12E-l 6 6.71E-07 944.71 m'lmin 15.75 m3/sec 3.0BE-15 4.IBE-16 4.64E-16 7 70E-07 9.95E-l4 l.35E-14 l.SOE-14 2.49E-05 l.lOE-13 l.l4E-14 8.99E-15 2.75E-05 3.40E-l5 3.53E-l6 2.78E-16 8.51 E-07 34.14 m3/min 0.57 m3/sec 6.14E-l 5 l.14E-15 l.23E-15 5.SSE-08 I 98E-13 3.67E-14 3 97E-14 l.79E-06 2 07E-14 l.74E-14 2.61E-14 1.88E-07 6.41 E-16 5.37E-16 8.07E-l6 5.80E-09 29.44 m3/mln 0.49 m3tsec 2.07E-15 8.28E-16 8.97E-16 l.61E-08 6.68E-l4 2.68E-14 2.90E-14 5.21E-07 l.02E-14 1.13E-14 l.96E-14 7.95E-08 3.JSE-16 3.49E-16 6.07E-16 2.46E-09 111.96 m3/min l.87 m'tsec l.35E-I 5 6.97E-16 8.89E-16 4.00E-08 4.36E-l4 2.25E-14 2.88E-14 l.29E-06 2.13E-15 8.06E-l 5 l.90E-14 6.32E-08 6.59E-17 2.49E-16 5.86E-16 l.95E-09 291.18 m3/rnin 4.85 m3/sec 3.14E-15 5.20E-16 6 OIE-16 2.42E-07 l.02E-13 l.68E-14 l.94E-14 7.83E-06 9.99E-14 l.03E-14 1.26E-14 7.71E-06 3.09E-15 3.20E-16 3.89E-16 2.38E-07 53.21 m3/min 0.89 m3/sec l.28E-15 6.90E-16 8.69E-16 I.SOE-OS 21 G-26-0042 GOV-01-55 ACF-26-0061 Quantity Fnction Released of (g)

ECV 1

3.28E-10 5.03E-02 l.33E-05 5.03E-02 l.85E+OO l.89E-01 1.0IE-02 4.74E+o0 l.12E+OO l.SIE-01 2.00E+OO 4.19E-02 Total:

5.23E+OO 7.48E-09 3.BSE-03 l.47E-03 1.11 E-04 4.41E-03 2.20E+OO 3.94E-01 5.67E-02 Total:

2.26E+OO S.39E-10 7.67E-03 l.06E-04 2.20E-04 3.0IE-05 4.ISE-01 2.69E-03 l.07E-02 Total:

4.33E-Ol l.56E-l0 2.58E-03 3.08E-05 7.43E-05 l.27E-05 2.04E-Ol l.14E-03 S.2SE-03 Total:

2.12E-Ol 3.88E-10 l.69E-03 7.65E-OS 4.8SE-05 l.OIE-05 4.26E-02 9.0SE-04 l.lOE-03 Total:

4.SSE-02 2.35E-09 3.92E-03 4.63E-04 l.13E-04 l.24E-03 2.00E+OO I.IOE-01 5.ISE-02 Total:

2.0SE+OO l.75E-IO l.60E-03 ECV: Etnuen4 Conc1mlralion Value h1>m 1 O-CFR-20, Appendix 8 Fracilon of ECV al !he stack Is provided for reference only Concentrallons al off-site locatlons are significantly less than I hose repor1ed here (al s1ack} due 10 lhe atmospttertc dispersion lhat occurs before ll'U! effluent exils the sile Note: A value of *O"' was subsllluted for negative analytlcal results Printed: 02/04/2026 NFS - EDMS Page I of3 Page 7 of 14

Total Volume Location (m3)

Stack 615 Bldg. 306-W Tc-99 14,097,822 U-234 14,097,822 U-235 14,097,822 Stack 646 Bldg. 110 Pu-241 8,778,314 Tc-99 8,778,314 U-234 8,778,314 U-235 8,778,314 Stack 701 Bldg. 307 Pu-241 33,453,581 Tc-99 33,453,581 U-234 33,453,581 U-235 33,453,581 Stack 702 Bldg. 307 Pu-241 41,790,451 Tc-99 41,790,451 U-234 41,790,451 U-235 41,790,451 Stack 703 Exhaust Room Air Pu-241 110,580,172 Th-228 110,580,172 Th-230 110,580,172 Th-232 110,580,172 U-234 110,580,172 U-235 110,580,172 U-238 110,580,172 Stack 773 Bldg. 440 Pu-241 45,707,256 Th-228 45,707,256 Th-230 45,707,256 Th-232 45,707,256 U-234 45,707,256 U-235 45,707,256 Radioactivity in Effluent Air July 1, 2025 to December 31, 2025 Activity Error Quantity Concentration Estimate LLD Released

(µ.Ci/ml)

(µ.Ci/ml)

(µ.Ci/ml)

(Ci) 53.21 m'/min 0.89 m3/sec 4.14E-14 2.23E-14 2.81E-14 5.83E-07 l.88E-l 5 8.20E-15 l.91E-14 2.65E-08 5.81E-17 2.54E-16 5.91E-16 8.19E-10 33.13 m'/min 0.55 m3tscc 1 57E-15 7.36E-16 8.81E-16 l.37E-08 5.06E-14 2.38E-14 2.85E-14 4.44E-07 l.86E-14 9.SOE-15 1.95E-14 1.63E-07 5.74E-16 2.94E-16 6.02E-l 6 5.04E-09 126.11 mo/min 2.10 m3/sec I.SIE-15 8.0IE-16 I.OOE-15 5.06E-08 4.89E-14 2.59E-14 3.23E-14 l.63E-06 9.63E-l 5 1 ISE-14 2.20E-14 3.22E-07 2.98E-16 3.54E-16 6.80E-16 9.96E-09 157.59 m3/min 2.63 m 3/scc l.35E-l 5 7.06E-16 8.75E-1 6 5.62E-08 4.35E-14 2.28E-14 2.83E-14 1.82E-06 2.14E-14 I lOE-14 1.93E-14 8.93E-07 6.61 E-16 3.41E-16 5.97E-16 2.76E-08 417.49 m3/min 6.96 m3/sec 4.90E-l 4 2.62E-14 3.29E-14 5 42E-06 9 09E-16 I 17E-IS 2 22F.-15 I.QI E-07 5.23E-l 6 6.74E-16 l.28E-15 5.79E-08 7.44E-l 6 9.58E-16 l.82E-15 8.22E-08 5.69E-t 5 7.33E-1 S I.39E-14 6.29E-07 5.88E-16 7.57E-16 1.43E-15 6.SOE-08 7.16E-16 9.23E-16 I 75E-15 7.92E-08 172.SI mo/min 2.88 m3/sec 4.73E-14 2.82E-14 3.57E-14 2.16E-06 1.14E-16 l.38E-l 5 3.46E-15 5.23E-09 1.47E-16 l.78E-15 4.44E-15 6.72E-09 9.81E-17 l.lSE-15 2.96E-15 4.48E-09 3.02E-16 3.6SE-l 5 9.13E-15 l.38E-08 5.31 E-17 6.41 E-16 l.60E-15 2.43E-09 21 G-26-0042 GOV-01-55 ACF-26-0061 Quantity Fraction Released of (g)

ECV 1

3.45E-05 4.60E-05 4.25E-06 3.76E-02 3.79E-04 9.69E-04 Total:

4.02E-02 IJ3E-IO l.96E-03 2.63E-05 5.62E-05 2.61E-05 3.71E-Ol 2.33E-03 9.57E-03 Total:

3.83E-01 4.91E-IO l.89E-03 9.67E-05 5.43E-05 5.16E-05 l.93E-Ol 4.61E-03 4.96E-03 Total:

1.99E-0I 5.46E-JO l.68E-03 l.08E-04 4.83E-05 l.43E-04 4.27E-Ol l.28E-02 I. lOE-02 Total:

4.40E-01 5.26E-08 6.12E-02 1 23E-10 4.54E-02 2.86E-06 2.62E-02 7.54E-01 l.86E-Ol 1.0 I E-04 l.14E-Ol 3.01 E-02 9.79E-03 2.36E-Ol l.l 9E-02 Total:

454E-Ol

2. lOE-08 5.91E-02 6.38E-12 S.72E-03 3.33E-07 7.35E-03

4. I I E--02 2.45E-02 2.21E-06 6.0SE-03 l.12E-03 8.85E-04 ECV: Effluent Concentration Value from 10-CFR-20, Appendix 8 Fraction of ECV al the stack Is provided lor rererence only Concentrallons at off-site locations are slgnincantly less than those ~ported here (at slack) due lo lhe atmospheric dtsper3lon 1h11 oceu~ before the effluent e1etts the site.

Note: A value of "O" was subs41tuled lor neoative analytical results.

Printed: 02/04/2026 NFS-EDMS Page 2 of3 Page 8 of 14

Total Volume Location (m3)

Stack 773 Bldg. 440 U-238 45,707,256 Stack 796 Bldg. 100 Pu-241 4.917,454 Tc-99 4,917,454 U-234 4,917,454 U-235 4,917,454 1

Radioactivity in Effluent Air July 1, 2025 to December 31, 2025 Activity Error Quantity Concentration Estinrnte LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci) 172.51 ml/min 2.88 m 3/sec l.06E-l6 l.28E-l 5 3.21E-15 4.86E-09 18.56 ml/min 0.JJ m3/sec l.69E-15 7.55E-16 8.67E-16 8.30E-09 5.46E-14 2 44E-14 2.SOE-14 2 68E-07 l 17E-15 775E-15 I.90E-14 5.77E-09 3.63E-l7 2.40E-16 5.87E-16 1.79E-10 21 G-26-0042 GOV-01-55 ACF-26-0061 Quantity Fraction Released of 1

(g)

ECV 1.45E-02 l.77E-03 Total:

l.0SE-01 8.06E-1 l 2.11 E-03 1.59E-05 6.06E-05 9.25E-07 2.35E-02 8.27E-05 6.0SE-04 Total:

2.63[-02 ECV: Effluent Concenlrallon Value from 10-CFR-20, Appendix a Fraction of ECV at the s1ec:k Is provided for ~ference onlv. Concentrations al orr-sue locatlons are slgnlnoanll)' less lhan those reported here (at stack) due to the atmospherfc dispersion lh1tl occu~ before the effluent exits the slle Note: A value of "O* was sub5tl1uted for negallve analytlcal results, Printed: 02/04/2026 NFS-EDMS Page 3 of3 Page 9 of 14 To Letter Dated February 16, 2026 21 G-26-0042 GOV-01 -55 ACF-26-0061 Report of Gaseous Effluent Dose and Activity Concentrations for the Maximally Exposed Off-Site Individual for the Release Period July to December 2025 (4 Pages to Follow)

Page 10 of 14

21 G-26-0042 GOV-01-55 ACF-26-0061 Report of Potential Gaseous Effluent Dose to the Maximally Exposed Offsite Individual and on the Maximum Radionuclide Concentrations for the Period:

July to December 2025 Introduction During this biannual period, NRC License SNM-124, Section 9.1.1.3, required NFS to assess the total effective dose equivalent (TEDE) to the maximally exposed offsite receptor and the maximum radioactive air concentrations at the site boundary attributable to NFS' air effluents. The required biannual assessment has been completed and the details of the assessment are provided in the subsequent sections.

Summary of Methods In accordance with SNM-124, Section 9.1.1.4, and internal procedure NFS-HS-A-27, the U.S. Department of Energy's CAP88-PC computer program was used to estimate off-site doses and activity concentrations for gaseous effluents. NFS operated thirteen (13) radiological stacks during the second half of 2025. Based on effluent types and stack physical characteristics, releases from these stacks were grouped into effective stacks for modeling purposes. To accommodate the co-location limitation of the model, the effective stacks were taken to be at the approximate center of the plant site. The distance to the site boundary (nearest model receptor distance) was conservatively taken to be 150 meters for all sectors.

Meteorological data was based on the average wind speed and direction frequencies from the onsite meteorological tower covering the time period for this report.

Atmospheric stability class D (neutral atmosphere) was used for all releases (default value recommended by the U.S. Environmental Protection Agency in "User's Guide for COMPLY"). The most conservative inhalation class was assumed for each radionuclide released. A particle size (activity median aerodynamic diameter or AMAD) of 1.0 micron was assumed for modeling purposes since no information on actual particle sizes exists.

Because CAP88-PC models releases over an entire year, the six-month source term (i.e., total curies of each radionuclide released over the period, given in Attachment 2) was annualized (i.e., transformed into a 12-month release) so that airborne activity concentrations would not be under-estimated during the release period.

Summary of Results Doses are reported in Table 1 below and are derived from the CAP88-PC "Synopsis Report." These doses are at the location of the maximally exposed (off-site) individual (MEI). The results include an adjustment (using the normalization factor mentioned above) to convert the "annualized" doses back to those doses that were actually received in the six-month release period. Activity concentrations reported in Table 2 come directly from the CAP88-PC "Concentration Tables" report; no adjustments are needed for these concentrations. The CAP88-PC output reports are available for review at NFS.

Page 11 of 14

21 G-26-0042 GOV-01-55 ACF-26-0061 Table 1 summarizes the six-month dose to a hypothetical individual at the MEI location, which was determined to be approximately 450 meters Northeast from the center of the plant site. The TEDE to the MEI was estimated to be 4.8E-03 mrem for gaseous effluents released during the second half of 2025. The highest organ committed dose equivalent (COE) to the MEI was estimated to be 2.4E-02 mrem to the lungs. These MEI doses are well below the Environmental Radiological Monitoring Program action levels and applicable regulatory limits/ALARA constraints.

Table 1. Organ Doses and Total Effective Dose Equivalent at the MEI Location Organ Adrenals Urinary Bladder Wall Bone Surface Brain Breasts Stomach Wall Small Intestine Upper Large Intestine Wall Lower Large Intestine Wall Kidneys Liver Muscle Ovaries Pancreas Red Bone Marrow Skin Spleen Testes Thymus Thyroid Gall Bladder Wall Heart Wall Uterus Extra-thoracic Lungs Total Effective Dose Equivalent Location of MEI:

Committed Dose Equivalent (mrem per second half of 2025) 3.4E-04 4.1 E-04 1.3E-02 3.4E-04 3.6E-04 7.0E-03 3.9E-04 2.0E-03 5.0E-03 4.0E-03 1.2E-03 3.5E-04 3.7E-04 3.4E-04 1.7E-03 7.0E-04 3.4E-04 3.9E-04 3.4E-04 3.6E-03 3.4E-04 3.4E-04 3.4E-04 2.0E-02 2.4E-02 4.BE-03 mrem 450 meters Northeast Page 12 of 14

21 G-26-0042 GOV-01-55 ACF-26-0061 Table 2 summarizes the maximum radioactive air concentrations at or beyond the site boundary, as determined by CAP88-PC, for the radionuclides released. The total sum of fractions was estimated to be 7.9E-04 and indicates that exposures to the offsite public from gaseous effluents were much less than 1 % of the 10 CFR 20, Appendix B, Table 2, Col. 1 values for all offsite receptors including the site boundary. It is noted that the location of the maximum airborne concentration for a given radionuclide does not necessarily correspond to the MEI location. This is due primarily to the fact that the maximum concentrations for individual nuclides can vary due to differences in values input into the dispersion model for each of the effective stacks - such inputs include stack height, stack diameter, flow rate, and total radionuclide activities released per stack. Another reason for the disparity is the fact that the MEI dose includes both inhalation and ingestion pathways.

Table 2. Maximum Predicted Airborne Concentrations at or Beyond the Site Boundary Maximum Predicted Airborne Concentrations at "I

or Beyond the Site Boundary Maximum Concentration 10 CFR 20, App. B, Ratio of Maximum Nuclide Concentration Location Table 2, Col. 1 Value Concentration to

(µCilmL)

Sector Dist (m)

(µCilmL) 10 CFR 20 Value 99Tc 3.0E-1 7 NE 400 9.E-10 3.3E-08 22sTh 1.3E-19 NE 500 2.E-14 6.3E-06 230T h 9.7E-20 NE 550 2.E-14 4.9E-06 232Th 1.0E-19 NE 500 4.E-15 2.5E-05 234u 3.6E-17 NE 500 5.E-14 7.2E-04 23su 1.2E-18 NE 500 6.E-14

2. IE-05 23su 2.0E-19 NE 600 6.E-14 3.3E-06 238Pu 0.0E+-00 NIA NIA 2.E-14 0.0E+-00 239Pu 0.0E+-00 NIA NIA 2.E-14 0.0E+-00 24 1Pu 8.0E-1 8 NE 350 8.E-13 l.0E-05 24 1A m 8.0E-26 NE 550 2.E-14 4.0E-12 Sum of Fractions:

7.9&04 NIA: Not Applicable due to 0.0 max. concentration.

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21 G-26-0042 GOV-01-55 ACF-26-0061 The TEDE to the MEI for gaseous effluents released during 2025 is provided in Table 3.

The results for the 1st half of 2025 were previously reported in Biannual Effluent Monitoring Report January to June 2025 (21G-25-0126). The annual dose is well below the Environmental Radiological Monitoring Program action levels and applicable regulatory limits/ALARA constraints.

Table 3. Annual Dose to the MEI for Gaseous Effluents Released During 2025 Period Direction Distance TEDE Covered (m)

(mrem) 2nd Half NE 450 4.8E-03 1st Half NNE 550 3.5E-03 Annual Total 8.3E-03 Page 14 of 14