DRC-2025-001127

299 South Main Street, Suite 1700 ▪ Salt Lake City, Utah 84111
[phone] ▪ Fax: [phone] ▪ www.energysolutions.com

April 4, 2025 CD-2025-064

Mr. Doug Hansen, Director
Division of Waste Management and Radiation Control
P.O. Box 144880
Salt Lake City, UT 84114-4880

Re: Groundwater Quality Discharge Permit Number UGW450005 (GWQDP) –
Response to Request for Additional Information (RFI) Regarding Notification and
Resolution of BAT Concern: 1997 Evaporation Pond Pump and Transducer

Dear Mr. Hansen:

On February 11, 2025 the BAT inspector discovered that the 1997 Evaporation Pond
pump operation could not be verified. Clive Maintenance personnel were notified the
same day to verify it was working. On February 12, 2025 the BAT inspector found that
repairs were still ongoing, and the daily fluid head reading could not be read from the
process controller. On February 13, 2025, the transducer and pump were replaced, the
system was tested, and normal operations were restored.

EnergySolutions provided the necessary 24-hour and seven-calendar-day notifications to
the Division of Waste Management and Radiation Control (Division) on February 12,
2025 and February 17, 2025 (CD-2025-028), respectively.

On April 1, 2025, the Division responded with an RFI (DRC-2025-001025):

Please describe how the dysfunctional transducer was accounted for in
calculating the seven-day average flow rate at the 1997 Evaporation Pond and
provide the associated Evaporation Ponds Leak Detection System Volume Weekly
Calculation Form to verify compliance with Part 1.F.13 and Appendix J Table 1
of the Permit for the time of this event.

Review of the daily LLRW/11e.(2) inspection forms (Form 1) for the week of February
10 to 16, 2025 documents the fluid head level was 0.56 feet on February 11, 2025 and
0.62 feet on February 14, 2025. The leak detection system was inoperable on February
12 and 13, 2025, and therefore, fluid head readings could not be documented on these
days. The fluid head level of the 1997 Pond did not exceed the GWQDP Appendix K Part
4.1.6 limit of 1 foot at any time during the week. We believe these issues were at least
partially the result of extremely low winter temperatures. Our meteorological station
recorded a low of -3 degrees Fahrenheit that week.

Mr. Doug Hansen
April 4, 2025
CD-2025-064
Page 2 of 2

The totalizer meter records the volume of water pumped into the pond from the leak
detection system sump. This meter is mechanical and operates independently of
transducer and pump. For the week of February 10 to 16, 2025, no water was pumped
from the leak detection system, as the average leakage rate of the 1997 Evaporation Pond
for the week was 0.00 gallons (see attached Weekly Calculation Form). Had average
leakage rate exceeded the Initial Action Level or Allowable Leakage Rate for the week,
EnergySolutions would be required to provide a separate notification in accordance with
GWQDP Appendix K Part 4.1.4 or Part 4.1.5, respectively.

In summary, although the transducer of the 1997 Evaporation Pond leak detection system
was replaced along with the pump, it does not appear the transducer was malfunctioning.
The system did not pump any water during the week of February 10 to 16, 2025, and
therefore, a separate notification for exceedance of the average leakage rate was not
required. In addition, the Weekly Calculation Form (all of which are included in each
Semi-Annual BAT Report) is not required to verify compliance with an inoperable leak
detection system event because average leakage rate exceedance notifications are
required by GWQDP Appendix K. Had the inoperable leak detection system resulted in
exceedance of the average leakage rate, notification would have been provided to the
Division as a separate subsequent notice.

Please contact me at [phone] with any questions regarding this response.

Sincerely,

Mathew R. Schon
Manager, Groundwater and Environmental Program

I certify under penalty of law that this document and all attachments were prepared under my direction or supervision in accordance
with a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry
of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information
submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for
submitting false information, including the possibility of fine and imprisonment for knowing violations.