ML25237A035

Nuclear Fuel Services, Inc., Biannual Effluent Monitoring Report January to June 2025

ML25237A035
Person / Time
Site:	Erwin
Issue date:	08/18/2025
From:	Rogers D BWXT Nuclear Fuel Services, Nuclear Fuel Services
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards
References
21G-25-0126, GOV-01-55, ACF-25-0207
Download: ML25237A035 (1)

Text

B 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 21G-25-0126 GOV-01-55 ACF-25-0207 August 18, 2025

Subject:

Biannual Effluent Monitoring Report January to June 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 January to June 2025. Attachment 2 reports the Radioactivity in Effluent Air for the period January to June 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 January to June 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-25-0126) in any correspondence concerning this letter.

Sincerely, NUCLEAR FUEL SERVICES, INC.

~>>7a Danielle Roger~ (,'"~

Safety & Safeguards Director CJB/las Attachments

1) Report of Radioactivity in Effluent Liquid for the Period January to June 2025

2) Report of Radioactivity in Effluent Air for the Period January to June 2025

3) Report of Gaseous Effluent Dose and Activity Concentrations for the Maximally Exposed Off-Site Individual for the Release Period January to June 2025 1205 Banner Hill Rd, Erwin, TN 37650 Page 1 of13 People Stro ng t: +1.423.743.9141 I: +1.423.743.0140 www.nuclearfuelservices.com INNOVATION DRIVEN >

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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 13 21G-25-0126 GOV-01-55 ACF-25-0207 To Letter Dated August 18, 2025 Report of Radioactivity in Effluent Liquid for the Period January to June 2025 (2 Pages to Follow)

Page 3 of 13 21G-25-0126 GOV-01-55 ACF-25-0207

Total Volume Location (I)

Banner Spring Down Pu-238 348,860,000 Pu-239/240 348,860,000 Tc-99 348,860,000 Th-228 348,860,000 Th-230 348,860,000 Th-232 348,860,000 U-233/234 348,860,000 U-235/236 348,860,000 U-238 348,860,000 Sewer Pu-238 25,138,843 Pu-239/240 25, 138,843 Tc-99 25,138,843 Th-228 25,138,843 Th-230 25, 138,843 Th-232 25, 138,843 U-232 25,138,843 U-233/234 25,138,843 U-235/236 25,138,843 U-238 25,138,843 West Ditch Pu-238 11 9,884,000 Pu-239/240 119,884,000 Tc-99 11 9,884,000 Th-228 11 9,884,000 Th-230 11 9,884,000 Th-232 119,884,000 U-233/234 119,884,000 U-235/236 119,884,000 U-238 119,884,000 WWTF Am-24 1 4,144,70 1 Cs-137 4,144,70 1 Na-22 4,144,70 1 Np-237 4,144,70 1 Pb-212 4,144,701 Pu-238 4,144,70 1 Radioactivity in Effluent Liquid January 1, 2025 to June 30, 2025 Activity Error Quantity Concentration Estimate LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci) 1.24E-1 2 1.17E-10 2.59E-10 4.34E-07 1.95E-11 1.41E-10 2.90E-10 6.80E-06 0.00E+00 4.08E-08 7.13E-08 0.00E+00 4.43E-l 1 l.96E-I0 3.66E-10 I.54E-05 1.16E-1 0 1.98E-10 3.32E-10 4.06E-05 0.00E+00 9.4 1E-11 1.99E-10 0.00E+00 I.0IE-09 3.40E-10 2.91E-10 3.54E-04 6.84E-11 1.18E-10 1.84E-10 2.39E-05 l.34E-10 l.48E-10 1.89E-10 4.66E-05 0.00E+00 7.18E-1 I l.77E-I 0 0.00E+00 0.00E+00 6.00E-11 1.52E-10 0.00E+00 8.70E-09 4.12E-08

7. I0E-08

2. I 9E-04 2.56E-l l l.79E-l 0 3.60E-10 6.44E-07 2.20E-10 2.SSE-10 3.76E-10 5.53E-06 7.18E-12 I.I 9E-l 0 2.S0E-10 1.81 E-07 0.00E+00 I.SSE-I 0 3.45E-10 0.00E+00 l.12E-08 l.16E-09 2.26E-I0 2.83E-04 7.08E-10 3.06E-I0

2. 12E-10 l.78E-05 l.45E-09 4.28E-10 1.66E-10 3.66E-05 1.13E-11 l.22E-10 2.66E-10 l.36E-06 0.00E+00

1. I 7E-10 2.60E-I0 0.00E+00 0.00E+00 4.27E-08 7.49E-08 0.00E+00 8.20E-11 1.91E-I0 3.41 E-10 9.83E-06 6.35E-l 1 2.28E-10 4.4 1E-10 7.6 1E-06 5.23E-l 1 l.64E-10 2.90E-10 6.27E-06 l.20E-08 l.20E-09 2.88E-10 1.44E-03 5.0IE-10 2.81 E-10 l.86E-I0 6.00E-05 9.91E-10 3.56E-10 2.23E-10 l.19E-04 3.89E-II 1.66E-10 3.08E-10 1.61 E-07 0.00E+00 1.41 E-09 2.09E-09 0.00E+00 0.00E+00 1.21 E-09 2.22E-09 0.00E+00 2.0IE-10 3.40E-10 S.52E-I 0 8.35E-07 I.85E-09 4.46E-09 4.43E-09 7.68E-06 0.00E+00 8.41E-l 1 2.20E-10 0.00E+00 ECV: Effluent Concentration Value from 10.CFR*20, Appendix B Note A value of *o* was substituted for negative analy11cal resutts Printed: 08/06/2025 NFS-EDMS Page 4 of 13 Quantity Released (g) 2.54E-08 l.09E-04 0.00E+00 I.89E-08 2.0 I E-03 0.00E+00 5.67E-02 I.I 0E+0 I l.39E+02 Total:

0.00E+00 0.00E+00 l.29E-02 7.86E-10 2.74E-04 l.66E+00 0.00E+00 4.53E-02 8.24E+00 l.09E+02 Total:

7.94E-08 0.00E+00 0.00E+00 I.20E-08 3.77E-04 5.75E+0 I 2.30E-0I 2.78E+0I 3.55E+02 Total:

4.70E-08 0.00E+00 0.00E+00 I. I 9E-03 5.SSE-12 0.00E+00 21 G-25-0126 GOV-01-55 ACF-25-0207 Fraction of ECV 1

6.22E-05 9.74E-04 0.00E+00 2.2 1E-04 1.16E-03 0.00E+00 3.38E-03 2.28E-04 4.45E-04 6.48E-03 0.00E+00 0.00E+00 l.45E-05 l.28E-05 2.20E-04 2.39E-05 0.00E+00 3.75E-03 2.36E-04 4.85E-04 4.74E-03 5.66E-04 0.00E+00 0.00E+00

4. 1 0E-04 6.35E-04 l.74E-03 3.99E-02 1.67E-03 3.30E-03 4.82E-02 I.95E-03 0.00E+00 0.00E+00 I.0IE-02 9.26E-04 0.00E+00 Page I of2

Radioactivity in Effluent Liquid January 1, 2025 to June 30, 2025 Total Activity Volume Concentration Location (I)

(µCi/ml)

WWTF Pu-239/240 4,144,701 0.00E+00 Pu-24I 4,144,701 0.00E+00 Tc-99 4,144,701 6.35E-08 Th-228 4,144,701 0.00E+00 Th-230 4,144,701 1.70E-I0 Th-231 4,144,701 0.00E+00 Th-232 4,144,701 0.00E+00 U-232 4,144,701 9.18E-12 U-233/234 4,144,701 3.96E-08 U-235/236 4,144,701 2.21E-09 U-238 4,144,701 4.36E-10 ECV: Effluent Concentration Value from 1 0-CFR-20, Appendix 8.

Note: A value of "O~ was subs1ituted for negative analytical results.

Printed: 08/06/2025 Error Quantity Estimate LLD Released

(µCi/ml)

(µCi/ml)

(Ci) l.0IE-10 2.37E-I0 0.00E+00 1.71 E-08 2.99E-08 0.00E+00 l.29E-07 2.I9E-07 2.63E-04 1.79E-10 3.79E-I0 0.00E+00 2.43E-10 3.81E-10 7 0SE-07 4.66E-08 5.90E-08 0.00E+00 1.04E-I0 2.34E-10 0.00E+00 l.23E-10 2.57E-10 3.80E-08 1.47E-09 l.55E-10 l.64E-04 3.48E-10 1.28E-10

9. l SE-06 l.57E-l 0 l.30E-10 1.8 I E-06 NFS* EDMS Page 5 of 13 21G-25-0126 GOV-01-55 ACF-25-0207 Quantity Fraction Released of (g)

ECV 1

0.00E+00 0.00E+00 0.00E+00 0.00E+00 l.56E-02 1.06E-03 0.00E+00 0.00E+00 3.49E-05 l.70E-03 0.00E+00 0.00E+00 0.00E+00 0.00E+00 l.78E-09 l.53E-04 2.63E-02 l.32E-0l 4.23E+00 7.36E-03 5.39E+00 1.45E-03 Total:

I.S7E-01 Page 2 of2 To Letter Dated August 18, 2025 Report of Radioactivity in Effluent Air for the Period January to June 2025 (3 Pages to Follow)

Page 6 of 13 218-25-0126 GOV-01-55 ACF-25-0207

Total Volume Location (ml)

Main Stack 416 Th-228 268,969,820 Th-230 268,969,820 Th-232 268,969,820 U-234 268,969,820 U-235 268,969,820 U-238 268,969,820 Stack 327 Bldg. 330 Pu-241 252,575,845 Tc-99 252,575,845 U-234 252,575,845 U-235 252,575,845 Stack 421 Bldg. 100 Pu-241 8,369,491 Tc-99 8,369,491 U-234 8,369,491 U-235 8,369,491 Stack 424 Bldg. I 00 Pu-241 7,284,557 Tc-99 7,284,557 U-234 7,284,557 U-235 7,284,557 Stack 573 Bldg 306-W Pu-241 28,691,729 Tc-99 28,691,729 U-234 28,691,729 U-235 28,691,729 Stack 600 Bldg. 110 Pu-241 78,654,926 Tc-99 78,654,926 U-234 78,654,926 U-235 78,654,926 Stack 615 Bldg. 306-W Pu-241 12,149,655 Radioactivity in Effluent Air January 1, 2025 to June 30, 2025 Activity Error Quantity Concentration Estimate LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci)

I032.ll m 3/min 17.20 m3tsec 1.0SE-15 1.84E-16 8.08E-l 7 2.83E-07 1.0SE-15 1.84E-16 8.08E-l 7 2.83E-07 7.90E-16 l.38E-16 6.06E-17 2.13E-07 2.48E-13 4.33E-14 1.91E-14 6.68E-05 9.49E-15 1.65E-15 7.28E-16 2.SSE-06 2.63E-15 4.59E-16 2 02E-16 7.09E-07 969.22 m 3/min 16.15 m3tsec 3.0SE-15 4.33E-16 4.98E-l 6 7.70E-07 9.86E-14 1.40E-14 1.61E-14 2.49E-05 9.61E-14 1.21 E-14 9.04E-l 5 2.43E-05 2.97E-15 3.75E-16 2.80E-16 7.51 E-07 32.11 m 3/min 0.54 m3tsec 6.45E-15 1.17E-15 l.25E-15 5.40E-08 2.09E-13 3.78E-14 4.04E-14 I. 75E-06 2.57E-14 l.70E-14 2.48E-14

2. I SE-07 7.95E-16 5.24E-16 7.67E-16 6.66E-09 27.95 m 3/min 0.47 m 3/sec 2.17E-15 9.16E-16 9.70E-16 I.58E-08 7.0lE-14 2.96E-14 3.14E-14 5.1 IE-07 5.63E-15 I.OSE-14 2.02E-14

4. IOE-08 I. 74E-l 6 3.26E-l 6 6.24E-16 l.27E-09 109.98 m 3/min 1.83 m3tsec 1.48E-15 7.33E-16 9.23E-16 4.24E-08 4.78E-14 2.37E-14 2.98E-14 1.37E-06 6.93E-16 7.28E-l 5 l.86E-14 I.99E-08 2.14E-l 7 2.25E-16 5.75E-16 6.ISE-10 301.71 m 3/min 5.03 m 3/sec 2.07E-15 5.IOE-16 6.37E-16 I.63E-07 6.68E-14 l.65 E-14 2.06E-14 5.26E-06 2.91E-14 9.0lE-15 l.25E-l 4 2.29E-06 9.0lE-16 2.79E-16 3.85E-16 7.08E-08 46.61 m 3/min 0.78 m3/sec l.30E-15 7.60E-16 9.55E-16 l.59E-08 218-25-0126 GOV-01-55 ACF-25-0207 Quantity Fraction Released of 1

(g)

ECV 3.46E-I 0 5.27E-02 I.40E-05 5.27E-02 l.95E+OO I.98E-O I l.07E-02 4.97E+OO I.I 8E+OO l.58E-O I 2.12E+OO 4.39E-02 Total:

5.47E+00 7.48E-09 3.81 E-03 1.47E-03 I.IOE-04 3.89E-03 l.92E+OO 3.48E-01 4.96E-02 Total:

1.98E+00 5.24E-10 8.07E-03 l.03E-04 2.32E-04 3.45E-05 5.14E-O I 3.08E-03 l.33E-02 Total:

5.36E-01 1.53E-10 2.71E-03 3.02E-05 7.79E-05 6.57E-06 1.13E-O I 5.87E-04 2.90E-03 Total:

l.18E-0 I 4.12E-IO l.85 E-03 8.12E-05 5.31 E-05

3. I 9E-06 l.39E-02 2.85E-04 3.57E-04 Total:

l.61E-02 I.58E-09 2.58E-03 3.11 E-04 7.42E-05 3.67E-04 5.82E-0 1 3.28E-02 l.SOE-02 Total:

6.00E-01 l.54E-l 0 l.63E-03 ECV: Effluent Concentration Value from 10-CFR-20, Appendix B. Fraction of ECV at the slack is provkted for reference only. Concentrations at off-site locations are slgnlflcantly less than those reported here (at stack) due lo the atmospheric dispersion that occurs before the effluent exits the site.

Note* A value of *o* was substituted for negative analytlcal resutts Printed: 08/06/2025 NFS-EDMS Page 1 of3 Page 7 of 13

Total Volume Location (ml)

Stack 615 Bldg. 306-W Tc-99 12,149,655 U-234 12,149,655 U-235 12,149,655 Stack 646 Bldg. 110 Pu-24I 10,419,151 Tc-99 10,419,151 U-234 10,419,151 U-235 10,419,151 Stack 701 Bldg. 307 Pu-24I 33,182,052 Tc-99 33, 182,052 U-234 33, 182,052 U-235 33, 182,052 Stack 702 Bldg. 307 Pu-24I 42,177,296 Tc-99 42,177,296 U-234 42,177,296 U-235 42,177,296 Stack 703 Exhaust Room Air Pu-24I 107,925,107 Th-228 107,925,107 Th-230 I 07,925, I 07 Th-232 107,925,107 U-234 I 07,925, I 07 U-235 I 07,925, I 07 U-238 I 07,925,107 Stack 773 Bldg. 440 Pu-24I 44,029,884 Th-228 44,029,884 Th-230 44,029,884 Th-232 44,029,884 U-234 44,029,884 U-235 44,029,884 Radioactivity in Effluent Air January 1, 2025 to June 30, 2025 Activity Error Quantity Concentration Estimate LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci) 46.61 ml/min 0.78 ml/sec 4.22E-14 2.46E-14 3.09E-14 5.13E-07 4.73E-16 7.75E-I5 l.98E-14 5.75E-09 l.46E-17 2.40E-l 6 6.14E-16 l.78E-IO 39.98 ml/min 0.67 ml/sec l.54E-15 7.99E-l 6 9.46E-l 6 1.61 E-08 4.98E-l4 2.58E-l4 3 06E-14 5.I9E-07 5.34E-16 7.69E-15 l.98E-I4 5.57E-09 l.65E-l 7 2.38E-I6 6.1 IE-16 1.72E-10 127.31 m3/min 2.12 m3tsec l.51E-15 8.65E-16 I.08E-15 5.02E-08 4.89E-14 2.80E-14 3.49E-I4 l.62E-06 4.69E-l 5 1.03E-l4 2.25E-I4 I.56E-07 1.45E-l 6 3.I8E-l6 6.94E-l6 4.81 E-09 161.82 m3/min 2.70 m3/sec l.37E-15 7.67E-I6 9.46E-I6 5.78E-08 4.43E-l4 2.48E-l4 3.06E-14 I.87E-06 4.99E-15 9.88E-15 1.97E-l 4

2. IOE-07 1.54E-16 3.06E-I6 6.09E-I6 6.51 E-09 414.08 m3/min 6.90 m3/sec 5.19E-14 2.91E-14 3.59E-14 5.61 E-06 4.31E-16 I.04E-15 2.29E-l 5 4.65E-08 2.48E-16 5.98E-16 l.32E-I5 2.68E-08 3.53E-16 8.50E-16 l.88E-15 3.81 E-08 2.70E-15 6.5IE-I5 I.44E-I4 2.91 E-07 2.79E-16 6.72E-16 l.48E-I 5 3.01 E-08 3.40E-16 8.I9E-16 1.81E-15 3.66E-08 169.19 m3/min 2.82 m3tsec 6.27E-14 3.I4E-I4 3.86E-l4 2.76E-06 2.21 E-16 I.42E-I5 3.43E-I5 9.72E-09 2.84E-16 1.82E-I5 4.41 E-15 I.25E-08 l.89E-16 1.22E-15 2.94E-15 8.33E-09 5.83E-16 3.75E-15 9.07E-l 5 2.57E-08 1.02E-I6 6.59E-16 l.59E-15 4.51 E-09 21 G-25-0126 GOV-01-55 ACF-25-0207 Quantity Fraction Released of (g)

ECV 1

3.03E-05 4.69E-05 9.22E-07 9.47E-03 8.24E-05 2.44E-04 Total:

t.14E-02 l.56E-l 0 I.93E-03 3.07E-05 5.54E-05 8.92E-07 I.07E-02 7.97E-05 2.75E-04 Total:

t.29E-02 4.87E-I0 l.89E-03 9.60E-05 5.43E-05 2.49E-05 9.38E-02 2.23E-03 2.42E-03 Total:

9.81E-02 5.6IE-I0 1.71 E-03 1.11 E-04 4.92E-05 3.37E-05 9.97E-02 3.01 E-03 2.57E-03 Total:

l.04E-01 5.44E-08 6.49E-02 5.68E-l l

2. I 5E-02 l.33E-06 1.24E-02 3.49E-0I 8.82E-02 4.67E-05 5.40E-02 l.39E-02 4.64E-03 1.09E-01 5.66E-03 Total:

2.51 E-01 2.68E-08 7.83E-02 I.I9E-l I I. IOE-02

6. l 9E-07 l.42E-02 7.64E-02 4.73E-02 4.12E-06 l. I 7E-02 2.09E-03 1.71 E-03 ECV* Effluent Concentration Value from 1 0-CFR-20, Appendix B. Fraction of ECV at the stack is provided lor reference only. Concentrations at off-site locations are s~nlflcantly 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 substituted for negative analytlcal results.

Printed: 08/06/2025 NFS-EDMS Page 2 of3 Page 8 of 13

Total Volume Location (m3)

Stack 773 Bldg. 440 U-238 44,029,884 Stack 796 Bldg. 100 Pu-241 4,753,044 Tc-99 4,753,044 U-234 4,753,044 U-235 4,753,044 Radioactivity in Effluent Air January 1, 2025 to June 30, 2025 Activity Error Quantity Concentration Estimate LLD Released

(µCi/ml)

(µCi/ml)

(µCi/ml)

(Ci) 169.19 m3/min 2.82 m3tsec 2.0SE-16 l.32E-l 5

3. 19E-1 5 9.03E-09 18.24 m3/min 0.30 m3/sec l.78E-15 8.37E-16 9.43E-16 8.47E-09 5.76E-14 2.7 1E-1 4 3.0SE-14 2.74E-07 9.07E-16 7.92E-15 l.96E-14 4.3 1 E-09 2.80E-17 2.45E-1 6 6.07E-1 6 l.33E-1 0 21G-25-0126 GOV-01-55 ACF-25-0207 Quantity Fraction Released of (g) 1 ECV 2.69E-02 3.42E-03 Total:

l.68E-0l 8.22E-l 1 2.23E-03 I.62E-05 6.40E-05 6.9 1E-07 1.81 E-02

6. I 7E-05 4.67E-04 Total:

2.09E-02 ECV Effluent Concentration Value from 10-CFR-20, Appendix B Fraction of ECV at the stack Is provided for reference only. Concentrations at off-site locellons 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 MOM was subsliluted for negallve analytical results.

Printed: 08/06/2025 NFS-EDMS Page 3 of3 Page 9 of 13 To Letter Dated August 18, 2025 21G-25-0126 GOV-01-55 ACF-25-0207 Report of Gaseous Effluent Dose and Activity Concentrations for the Maximally Exposed Off-Site Individual for the Release Period January to June 2025 (3 Pages to Follow)

Page 10 of 13

21G-25-0126 GOV-01-55 ACF-25-0207 Report of Potential Gaseous Effluent Dose to the Maximally Exposed Offsite Individual and on the Maximum Radionuclide Concentrations for the Period:

January to June 2025 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 first 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 Page 11 of 13

21G-25-0126 GOV-01-55 ACF-25-0207 needed for these concentrations. The CAP88-PC output reports are available for review at NFS.

Table 1 summarizes the six-month dose to a hypothetical individual at the MEI location, which was determined to be approximately 550 meters North-Northeast from the center of the plant site. The TEDE to the MEI was estimated to be 3.5E-03 mrem for gaseous effluents released during the first half of 2025.

The highest organ committed dose equivalent (COE) to the MEI was estimated to be 1.7E-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 first half of 2025) 2.5E-04 3.0E-04 9.6E-03 2.5E-04 2.6E-04 5.1 E-03 2.SE-04 1.5E-03 3.7E-03 2.9E-03 9.1 E-04 2.6E-04 2.?E-04 2.5E-04 1.2E-03 5.4E-04 2.5E-04 2.SE-04 2.5E-04 2.6E-03 2.5E-04 2.5E-04 2.5E-04 1.4E-02 1.7E-02 3.5E-03 mrem 550 meters North-Northeast Page 12 of 13

21G-25-0126 GOV-01-55 ACF-25-0207 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 5. 7E-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

"'I Maximum Predicted Airborne Concentrations at or Beyond the Site Boundary Maximum Concentration 10 CFR20,App. B, Ratio of Maximum Nuclide Concentration Location Table 2, Col. 1 Value Concentration to (I..ICilmL)

Sector Dist (m)

(µCilmL) 10 CFR20 Value 99Tc 2.2£- 17 NNE 400 9.E-10 2.SE-08 22sTh 8.4£-20 NNE 600 2.E-14 4.2£-06 230Th 7.5£-20 NNE 650 2.E-14 3.8£-06 232Th 6.6£..20 NNE 600 4.E-15 1.6£..05 234u 2.6£- 17 NNE 600 5.E-14 5.1 E-04 23su 9.0E-19 NNE 600 6.E-14 1.5£-05 23su 1.6E-19 NNE 700 6.E-14 2.7£..06 23sPu 0.0E+o0 NIA NIA 2.E-14 0.0E+o0 239Pu 0.0E+o0 NIA NIA 2.E-14 0.0E+o0 241 Pu 7.7£-1 8 NNE 350 8.E-13 9.6£..06 241Am 9.7£..26 NNE 550 2.E-14 4.9£-12 Sum of Fractions:

5.7&04 NIA: Not Applicable due to 0.0 max. concentration.

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