ML25111A044

Nuclear Fuel Services, Inc. - Biannual Effluent Monitoring Report July to December 2024

ML25111A044
Person / Time
Site:	Erwin
Issue date:	02/25/2025
From:	Rogers D Nuclear Fuel Services
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards
References
21G-25-0029, GOV-01-55, ACF-25-0041
Download: ML25111A044 (1)

Text

Nuclear Fu e l Services, Inc.

Certified Mail Return Receipt Requested Director Office of Nuclear Material Safety & Safeguards U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Reference:

Docket No.70-143; SNM License 124 21 G-25-0029 GOV-01-55 ACF-25-0041 February 25, 2025

Subject:

Biannual Effluent Monitoring Report July to December 2024

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 2024. Attachment 2 reports the Radioactivity in Effluent Air for the period July to December 2024. 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 2024.

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-25-0029) in any correspondence concerning this letter.

Sincerely, NUCLEAR FUEL SERVICES, INC.

r<=L~ -.-Lt?*~

Danielle Rogers Safety & Safeguards Director CJB/las Attachments rz:rJ!e

L>Aj5> SZ b fVrf _5S

1) Report of Radioactivity in Effluent Liquid for the Period July to December 2024

2) Report of Radioactivity in Effluent Air for the Period July to December 2024

3) Report of Gaseous Effluent Dose and Activity Concentrations for the Maximally Exposed Off-Site Individual for the Release Period July to December 2024 Page 1 of 14 1205 Banner Hill Rd, Erwin, TN 37650 t: +1.423.743.9141 f: +1.423.743.0140 www.nuclearfuelservices.com Peopl e Stro ng INNOVATION DRIVEN >

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. Larry Harris Senior Resident Inspector U. S. Nuclear Regulatory Commission Page 2 of 14 21 G-25-0029 GOV-01-55 ACF-25-0041 To Letter Dated February 25, 2025 Report of Radioactivity in Effluent Liquid for the Period July to December 2024 (2 Pages to Follow)

Page 3 of 14 21 G-25-0029 GOV-01-55 ACF-25-0041

Radioactivity in Effluent Liquid July 1, 2024 to December 31, 2024 Total Activity Error Quantity Volume Concentration Estimate LLD Released Location (I)

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci)

Banner Spring Down Pu-238 431,862,320 4.28E-13 7.3 1 E-11 l.58E-10 I.85E-07 Pu-239/240 43 1,862,320 O.OOE+OO 7.47E-11 l.93E-10 O.OOE+OO Tc-99 431,862,320 O.OOE+OO 3.29E-08 5.86E-08 O.OOE+OO Th-228 43 1,862,320 l.27E-11 l.34E-10 2.86E-I0 5.SOE-06 Th-230 43 1,862,320 l.03E-1 0 2.00E-10 3.56E-10 4.45E-05 Th-232 43 1,862,320 O.OOE+OO 1.01 E-10 2.52E-l0 O.OOE+OO U-233/234 43 1,862,320 3.07E-10 2.26E-IO 2.69E-10 l.33E-04 U-235/236 431,862,320 2.94E-l 1 l.l SE-10 l.95E-l0 l.27E-05 U-238 431,862,320 9.40E-l l l.25E-I0 l.75E-l 0 4.06E-05 Sewer Pu-238 22,409,038 O.OOE+OO 8.7 1 E-l l 2.01 E-10 O.OOE+OO Pu-239/240 22,409,038 O.OOE+OO 9.8 1 E-l l 2.42E-l 0 O.OOE+OO Tc-99 22,409,038 2.08E-08 4.09E-08 7.00E-08 4.66E-04 Th-228 22,409,038 O.OOE+OO 1.73E-l0 3.89E-10 O.OOE+OO Th-230 22,409,038 1.95E-10 2.62E-I0 4.19E-l 0 4.38E-06 Th-232 22,409,038 5.0SE-13 1.21E-10 2.52E-l 0 I. l 3E-08 U-232 22,409,038 O.OOE+OO 1.66E-I 0 3.52E-l 0 O.OOE+OO U-233/234 22,409,038 7.94E-09 8.78E-l0 2.1 IE-lO l.78E-04 U-235/236 22,409,038 4.79E-l0 2.29E-l 0 l.91 E-IO l.07E-05 U-238 22,409,038 l. l 8E-09 3.45E-I 0 l.79E-l0 2.64E-05 West Ditch Pu-238 I 02,302,320 0.00E+OO 8.63E-11 1.9lE-IO 0.00E+OO Pu-239/240 l 02,302,320 O.OOE+OO l.09E-l0 2.SOE-l 0 O.OOE+OO Tc-99 l 02,302,320 O.OOE+OO 3.26E-08 5.82E-08 O.OOE+OO Th-228 l 02,302,320 O.OOE+OO l.l4E-l0 2.77E-l 0 O.OOE+OO Th-230 l 02,302,320 9.53E-l l l.85E-l0 3.34E-10 9.75E-06 Th-232 l 02,302,320 O.OOE+OO 8.53E-l l 2.04E-l0 O.OOE+OO U-233/234 l 02,302,320 l.58E-08 l.37E-09 2.69E-10 l.61E-03 U-235/236 I 02,302,320 7.14E-1 0 3.33E-10

2. ISE-10 7.30E-05 U-238 I 02,302,320 l.I9E-09 3.85E-I 0 2.16E-IO l.22E-04 WWTF Am-24 1 2,995,114 6.49E-l l l.2IE-IO l.85E-10 l.94E-07 Cs-137 2,995,114 4.6 l E-lO l.53E-09 2.36E-09 l.38E-06 Na-22 2,995,114 O.OOE+OO l.22E-09 2.19E-09 O.OOE+OO Np-237 2,995, 114 3.43E-l l 2.7 l E-lO 5.63E-l 0 l.03E-07 Pb-212 2,995,114 4.69E-10 3.60E-09 3.91E-09 l.40E-06 Pu-238 2,995,114 3.66E-11 7.28E-l l l.14E-l0 l.lOE-07 ECV: Effluent Concentration Value from 1 O-CFR-20, Appendix B.

Note: A value of "OM was substituted for negative analytical results.

Printed: 02/06/2025 NFS-EDMS Page 4 of 14 Quantity Released (g)

I.08E-08 O.OOE+OO O.OOE+OO 6.72E-09 2.2 1 E-03 O.OOE+OO

2. l 2E-02 5.88E+OO l.2 l E+02 Total:

O.OOE+OO O.OOE+OO

2. 76E-02 O.OOE+OO

2. l 7E-04 l.04E-O l O.OOE+OO 2.85E-02 4.97E+OO 7.88E+O l Total:

O.OOE+OO O.OOE+OO O.OOE+OO O.OOE+OO 4.83E-04 O.OOE+OO 2.59E-Ol 3.38E+O l 3.64E+02 Total:

5.67E-08 l.59E-08 O.OOE+OO l.46E-04 IOl E-12 6.40E-09 21 G-25-0029 GOV-01-55 ACF-25-0041 Fraction of 1

ECV 2.14E-05 O.OOE+OO O.OOE+OO 6.37E-05 I.03E-03 O.OOE+OO 1.02E-03 9.80E-05

3. l3E-04 2.SSE-03 O.OOE+OO O.OOE+OO 3.46£-05 O.OOE+OO l.95E-04 l.68E-06 O.OOE+OO 2.65E-03 1.60E-04 3.93E-04 3.43E-03 O.OOE+OO O.OOE+OO O.OOE+OO O.OOE+OO 9.53E-04 O.OOE+OO 5.26E-02 2.38E-03 3.97E-03 S.99E-02 3.25E-03 4.6lE-04 O.OOE+OO 1.71 E-03 2.34E-04 l.83E-03 Page I of2

Radioactivity in Effluent Liquid July 1, 2024 to December 31, 2024 Total Activity Volume Concentration Location (I)

(µCi/ml)

WWTF Pu-239/240 2,995,114 6.40E-l 1 Pu-241 2,995,114

4. 13E-09 Ra-224 2,995,114 I.40E-08 Tc-99 2,995,114 0.00E+00 Th-228 2,995,114 0.00E+00 Th-230 2,995, 114 2 06E-10 Th-231 2,995,114 I.14E-08 Th-232 2,995, 11 4 0.00E+00 U-232 2,995,114 4.93E-1 2 U-233/234 2,995,114 7.51 E-09 U-235/236 2,995,1 14 3.33E-I0 U-238 2,995,114 l.1 9E-10 ECV: Effluent Concentration Value from 10-CFR*20, Appendix B.

Note. A value of ~o" was substituted for negative analytical results Printed: 02/06/2025 Error Quantity Estimate LLD Released

(µCi/ml)

(µCi/ml)

(Ci) 7.70E-11 l.43E-10 1.92E-07 1.37E-08 2.37E-08 I.24E-05 8.41 E-09 l.49E-08

4. l 8E-0S 9.03E-08 1.58E-07 0.00E+00 I.39E-10 3.16E-10 0.00E+00 2.20E-10 3.57E-10

6. 16E-07 4.82E-08 5.57E-08 3.4 1E-0S 9.26E-I I 2.37E-10 0.00E+00 l.54E-I0 3.26E-10 I.48E-08 7.95E-10 2.65E-1 0 2.25E-05 l.96E-10 l.94E-10 9.98E-07 l.41E-10 2 02E-10 3.58E-07 NFS - EDMS Page 5 of 14 Quantity Released (g) 3.08E-06 l.20E-07 2.63E-1 0 0.00E+00 0.00E+00 3 0SE-05 6.40E-11 0.00E+00 6.90E-10 3.60E-03 4.62E-01 I.07E+00 Total:

21 G-25-0029 GOV-01-55 ACF-25-0041 Fraction of ECV 1

3.20E-03 4.13E-03 6.98E-02 0.00E+00 0.00E+00 2.06E-03 2.27E-04 0.00E+00 8.2 1 E-05 2.S0E-02 l.l lE-03 3.98E-04 1.13E-01 Page 2 of2 To Letter Dated February 25, 2025 Report of Radioactivity in Effluent Air for the Period July to December 2024 (3 Pages to Follow)

Page 6 of 14 21 G-25-0029 GOV-01-55 ACF-25-0041

Total Volume Location (ml)

Main Stack 416 Th-228 276,5 I 8,281 Th-230 276,5 I 8,281 Th-232 276,518,281 U-234 276,518,281 U-235 276,518,281 U-238 276,518,281 Stack 327 Bldg. 330 Pu-241 260,356,772 Tc-99 260,356,772 U-234 260,356,772 U-235 260,356,772 Stack 421 Bldg. 100 Pu-241 8,692,888 Tc-99 8,692,888 U-234 8,692,888 U-235 8,692,888 Stack 424 Bldg. 100 Pu-241 7,650,076 Tc-99 7,650,076 U-234 7,650,076 U-235 7,650,076 Stack 573 Bldg 306-W Pu-241 29,283,311 Tc-99 29,283,3 I I U-234 29,283,3 I I U-235 29,283,3 11 Stack 600 Bldg. II 0 Pu-241 80,993,649 Tc-99 80,993,649 U-234 80,993,649 U-235 80,993,649 Stack 615 Bldg. 306-W Pu-241 11,968,160 Radioactivity in Effluent Air July 1, 2024 to December 31, 2024 Activity Error Quantity Concentration Estimate LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci) 1032.40 m 3/min 17.21 m3tsec 9.93E-1 6 l.91E-I6 l.04E-16 2.75E-07 9.93E-16 l.91E-16 I.04E-16 2.75E-07 7.45E-16 l.43E-16 7.77E-l 7 2.06E-07 2.34E-13 4.49E-14 2.44E-14 6.47E-05 8.94E-15 1.71 E-15 9.33E-16 2.47E-06 2.48E-l 5 4.76E-16 2.59E-16 6.86E-07 972.06 m 3/min 16.20 m 3/sec 3.07E-l 5 4.22E-16 4.8 1E-I6 7.99E-07 9.92E-14 l.36E-14 l.56E-14 2.58E-05 9.07E-14 l.1 4E-14 8.71E-15 2.36E-05 2.80E-15 3.53E-16 2.69E-l 6 7.30E-07 32.43 m 3/min 0.54 m 3/sec 7.67E-l 5 l.4IE-15 l.48E-l 5 6.67E-08 2.48E-13 4.56E-14 4.79E-14 2.16E-06 l.56E-14 l.77E-14 2.95E-14 l.35E-07 4.82E-16 5.49E-16 9.13E-I6

4. I 9E-09 28.52 m 3/min 0.48 m3tsec 2.59E-15 l.04E-15 l.14E-15 I.98E-08 8.37E-14 3.38E-14 3.69E-14 6.40E-07 l.1 3E-14 l.34E-14 2.34E-14 8.65E-08 3.SOE-16

4. I SE-16 7.23E-16 2.68E-09 109.33 m 3/min 1.82 m3tsec 1.84E-15 8.79E-I6 I.09E-l 5 5.40E-08 5.96E-14 2.84E-14 3.52E-14 l.75E-06 4.93E-l 6 8.SSE-15 2.23E-14 l.44E-08 l.53E-17 2.64E-16 6.90E-16 4.47E-10 302.40 m 3/min 5.04 m 3/sec 2.SlE-15 5.27E-1 6 6.36E-16 2.04E-07 8.13E-14 l.70E-14 2.06E-14 6.58E-06 8.19E-14

l. I 7E-1 4 I.24E-14 6.63E-06 2.53E-I 5 3.63E-16 3.84E-16 2.0SE-07 44.68 m 3/min 0.74 m3tsec l.97E-15 l.09E-15 I.40E-15 2.35E-08 21 G-25-0029 GOV-01-55 ACF-25-0041 Quantity Fraction Released of 1

(g)

ECV 3.35E-10 4.96E-02 l.36E-05 4.96E-02 I.89E+OO l.86E-O I l.04E-02 4.68E+OO l.14E+OO l.49E-Ol 2.0SE+OO

4. 14E-02 Total:

5.16E+00 7.76E-09 3.84E-03 I.53E-03 l. IOE-04 3.78E-03 1.81 E+OO 3.38E-Ol 4.67E-02 Total:

l.86E+00 6.4 7E-l 0 9.59E-03 l.28E-04 2.76E-04 2.17E-05 3.12E-OI I.94E-03 8.03E-03 Total:

3.29E-01 l.92E-IO 3.23E-03 3.79E-05 9.30E-05 I.39E-05 2.26E-O l l.24E-03 5.83E-03 Total:

2.35E-01 5.24E-10 2.3 1 E-03 I.03E-04 6.63E-05 2.32E-06 9.87E-03 2.07E-04 2.54E-04 Total:

1.25E-02 l.98E-09 3.14E-03 3.90E-04 9.03E-05 I.06E-03 l.64E+OO 9.SOE-02 4.22E-02 Total:

l.68E+00 2.28E-IO 2.46E-03 ECV: Effluent Concentration Value from 1 O-CFR-20, Appendix B. Fraction of ECV at the stack Is provided for reference only. Concentrations at off-site locations are significantly less than those reported here (at stack) due to the atmospheric dispersion that occurs before the effluent exits the site.

Note: A value of "O" was substituted for negalive analytical results.

Printed: 02/06/2025 NFS-EDMS Page I of3 Page 7 of 14

Total Volume Location (ml)

Stack 615 Bldg. 306-W Tc-99 11,968, 160 U-234 11,968, 160 U-235 11,968, 160 Stack 646 Bldg. 110 Pu-241 11,528,265 Tc-99 11,528,265 U-234 11,528,265 U-235 11,528,265 Stack 701 Bldg. 307 Pu-241 33,346,666 Tc-99 33,346,666 U-234 33,346,666 U-235 33,346,666 Stack 702 Bldg. 307 Pu-241 44,555,327 Tc-99 44,555,327 U-234 44,555,327 U-235 44,555,327 Stack 703 Exhaust Room Air Pu-241 11 2,288,453 Th-228 I 12,288,453 Th-230 I 12,288,453 Th-232 11 2,288,453 U-234 11 2,288,453 U-235 112,288,453 U-238 I 12,288,453 Stack 773 Bldg. 440 Pu-241 44,277,640 Th-228 44,277,640 Th-230 44,277,640 Th-232 44,277,640 U-234 44,277,640 U-235 44,277,640 Radioactivity in Effluent Air July 1, 2024 to December 31, 2024 Activity Error Quantity Concentration Estimate LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci) 44.68 ml/min 0.74 ml/sec 6.36E-14 3.54E-14 4.54E-1 4 7.61 E-07 3.27E-16 l.02E-14 2.85E-1 4 3.92E-09 I.OIE-17 3.I SE-16 8.82E-l 6 1.21E-10 43.04 ml/min 0.72 ml/sec 2.49E-15

1. I 8E-15 1.41E-15 2.87E-08 8.0SE-14 3.83E-14 4.56E-14 9.28E-07 l.41 E-16 I.OSE-14 2.85E-14 l.63E-09 4.36E-18 3.24E-16 8.81E-16 5.0JE-11 124.41 ml/min 2.07 ml/sec l.37E-15 7.49E-16 9.56E-16 4.56E-08 4.42E-14 2.42E-14 3.09E-14 1.4 7E-06 3.00E-1 5 9.06E-l 5 2.04E-14 1.00E-07 9.29E-l 7 2.80E-16 6.JOE-16 3.IOE-09 166.14 ml/min 2.77 m3Jsec 1.40E-l 5 7.04E-16 8.58E-16 6.22E-08 4.52E-14 2.27E-14 2.77E-14 2.0IE-06 l.37E-14 l.08E-14 l.82E-l 4 6.12E-07 4.25E-16 3.34E-16 5.62E-16 l.89E-08 418.88 ml/min 6.98 ml/sec 4.23E-14 2.45E-1 4 3.21E-14 4.75E-06 3.63E-16 9.50E-l 6 2.08E-15 4.07E-08 2.09E-16 5.47 - 16 I.20E-15 2.35E-08 2.97E-16 7.77E-16 l.70E-15 3.33 E-08 2.27E-1 5 5.95E-l 5 l.30E-14 2.SSE-07 2.34E-l 6

6. 14E-16 l.34E-l 5 2.63E-08 2.86E-16 7.48E-16 l.64E-l 5 3.21 E-08 165.31 ml/min 2.76 m3Jsec 7.69E-14 3.98E-14 4.76E-14 HOE-06 I.75E-17 1.6 1E-15 4.30E-l 5 7.75E-IO 2.25E-l 7 2.07E-l 5 5.53E-l 5 9.96E-10 1.SOE-1 7 l.38E-15 3.68E-15 6.64E-10 4.63E-I 7 4.26E-l 5

1. 14E-14 2.0SE-09 8.13E-18 7.49E-16 2.00E-15 3.60E-10 21 G-25-0029 GOV-01-55 ACF-25-0041 Quantity Fraction Released of 1

(g)

ECV 4.50E-05 7.06E-05 6.28E-07 6.54E-03 5.6 1 E-05 1.69E-04 Total:

9.24E-03 2.79E-10 3.1 I E-03 5.49E-05 8.94E-05 2.60E-07 2.82E-03 2.33E-05 7.27E-05 Total:

6.09E-03 4.42E-I 0 1.71 E-03 8.72E-05 4.91E-05 I.60E-05 6.0IE-02 l.43E-03 I.SSE-03 Total:

6.34E-02 6.04E-10 l.75E-03 I. I 9E-04 5.02E-05 9.81 E-05 2.75E-0 1 8.77E-03 7.08E-03 Total:

2.84E-01 4.6 1 E-08 5.29E-02 4.97E-I I 1.8 I E-02 I.16E-06 I.04E-02 3.06E-OI 7.42E-02 4.09E-05 4.54E-02 l.22E-02 3.9 I E-03 9.58E-02 4.76E-03 Total:

2.IOE-01 3.3 I E-08 9.6 I E-02 9.46E-13 8.75E-04 4.93E-08 1.13E-03 6.09E-03 3.75E-03 3.28E-07 9.25E-04 l.67E-04 l.35E-04 ECV Effluent Concentration Value rrom ~ O-CFR-20, Appendix B. Fraction of ECV at the stack is provided for reference only. Concentrations at off-site locations are sigmficantly less than those reported here (at stack) due to the atmospheric dispersion that occurs before the effluent exits the site.

Note A value of ~a~ was substrtuted for negative analytical results.

Printed: 02/06/2025 NFS - EDMS Page2of3 Page 8 of 14

Total Volume Location (ml)

Stack 773 Bldg. 440 U-238 44,277,640 Stack 796 Bldg. 100 Pu-241 4,834,434 Tc-99 4,834,434 U-234 4,834,434 U-235 4,834,434 Radioactivity in Effluent Air July 1, 2024 to December 31, 2024 Activity Error Quantity Concentration Estimate LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci) 165.31 ml/min 2.76 ml/sec l.63E-17 I.SOE-IS 3.99E-1 5 7.20E-10 18.06 ml/min 0.30 ml/sec 2.26E-15 9.98E-I 6 l.14E-15 l.09E-08 7.JOE-14 3.23E-14 3.70E-14 3.53E-07 7.84E-16 9.IOE-15 2.JSE-14 3.79E-09 2.42E-l 7 2.82E-l 6 7.27E-16 l.l 7E-10 21 G-25-0029 GOV-01-55 ACF-25-0041 Quantity Fraction Released of (g)

ECV 1

2. 1 SE-03 2.71E-04 Total:

l.03E-0I l.06E-1 0 2.82E-03 2.09E-05 8.11 E-05 6.07E-07 l.57E-02 5.43E-05 4.04E-04 Total:

l.90E-02 ECV Effluent Concentration Value from 10-CFR-20, Appendix B. Fradion of ECV at the stack is provided for reference only. Concentrations at off-srte locations are slgmficantly less than those reported here (at stack) due to the atmospheric dispersion that occurs before the effluent exits the site.

Note A value of MO" was substituted for negalive analytical results.

Printed: 02/06/2025 NFS-EDMS Page 3 of3 Page 9 of 14 To Letter Dated February 25, 2025 21 G-25-0029 GOV-01-55 ACF-25-0041 Report of Gaseous Effluent Dose and Activity Concentrations for the Maximally Exposed Off-Site Individual for the Release Period July to December 2024 (4 Pages to Follow)

Page 10 of 14

21 G-25-0029 GOV-01-55 ACF-25-0041 Report of Potential Gaseous Effluent Dose to the Maximally Exposed Offsite Individual and on the Maximum Radionuclide Concentrations for the Period:

July to December 2024 Introduction During this biannual period, NRG 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 2024. 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-25-0029 GOV-01-55 ACF-25-0041 Table 1 summarizes the six-month dose to a hypothetical individual at the MEI location, which was determined to be approximately 500 meters North-Northeast from the center of the plant site. The TEDE to the MEI was estimated to be 4.6E-03 mrem for gaseous effluents released during the second half of 2024. The highest organ committed dose equivalent (COE) to the MEI was estimated to be 2.2E-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 2024) 3.3E-04 4.1 E-04 1.2E-02 3.3E-04 3.5E-04 7.3E-03 3.8E-04 2.0E-03 5.2E-03 3.8E-03 1.2E-03 3.4E-04 3.6E-04 3.3E-04 1.6E-03 6.8E-04 3.4E-04 3.7E-04 3.3E-04 3.8E-03 3.3E-04 3.3E-04 3.3E-04 1.8E-02 2.2E-02 4.6E-03 mrem 500 meters North-Northeast Page 12 of 14

21 G-25-0029 GOV-01-55 ACF-25-0041 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 7.2E-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 CFR20 Value 99Tc 3.0E-17 NNE 450 9.E-10 3.3E-08 228Th 8.9E-20 NNE 650 2.E-I4 4.5E-06 230Th 7.9E-20 NNE 700 2.E-14 4.0E-06 232T h 6.9E-20 NNE 650 4.E-I5 1.7E-05 234u 3.3E-17 NNE 600 5.E-I4 6.6E-04 23s u 1.IE-I8 NNE 600 6.E-14 l.9E-05 23su 1.8E-l 9 NNE 750 6.E-I4 3.0E-06 238 P u O.OE-+-00 NIA NI A 2.E-I4 O.OE-+-00 239 P u O.OE-+-00 NIA NIA 2.E-I4 O.OE-+-00 24 1Pu 9.3E-18 NNE 350 8.E-I3 l.2E-05 241A m 1.2E-25 NNE 550 2.E-14 6.0E-I2 Sum of Fractions:

7.2&04 NIA : Not Applicable due to 0.0 max. concentration.

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21 G-25-0029 GOV-01-55 ACF-25-0041 The TEDE to the MEI for gaseous effluents released during 2024 is provided in Table 3.

The results for the 1st half of 2024 were previously reported in Biannual Effluent Monitoring Report January to June 2024 (21G-24-0146). 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 2024 Per iod Direction Distance TEDE Cove red (m)

(mrem) 2nd H alf NNE 500 4.6E-03 1st H alf NNE 550 4.2E-03 Annual Total 8.8E-03 Page 14 of 14