IR 05000237/2020090
| ML20352A042 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 12/17/2020 |
| From: | David Curtis Division of Nuclear Materials Safety III |
| To: | Bryan Hanson Exelon Generation Co, Exelon Nuclear |
| Shared Package | |
| ML20353A400 | List: |
| References | |
| EA-20-053 IR 2020090 | |
| Download: ML20352A042 (10) | |
Text
December 17, 2020
SUBJECT:
REISSUE DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - NRC INSPECTION REPORT 05000237/2020090 AND 05000249/2020090
Dear Mr. Hanson:
This letter refers to the triennial heat sink inspection conducted from February 10, 2020, to March 31, 2020, (Inspection Report Nos. 05000237/2020001 and 05000249/2020001) and from April 1, 2020, to April 24, 2020, (Inspection Report Nos. 05000237/2020012 and 05000249/2020012) at Dresden Nuclear Power Station, Units 2 and 3. The purpose of the inspection was to monitor licensee performance in accordance with the Reactor Oversight Process. The results of this inspection were discussed with Mr. P. Karaba, Site Vice President and other members of your staff on April 24, 2020. The inspection reports provided above can be found in the NRCs Agencywide Document Access and Management System (ADAMS) at Accession Nos. ML20133J811 and ML20140A181, respectively. ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html.
The NRC is reissuing this report to correct the administrative tracking number associated with the apparent violation and to formally close apparent violation 05000237,05000249/2020012-02 in our inspection item tracking system.
The NRC has determined the apparent violation described in Inspection Report 05000237/2020012; 05000249/2020012 (AV 05000237,05000249/2020012-02) is a Severity Level IV violation of NRC requirements. The NRC concluded this violation was best characterized as a Severity Level IV violation based upon example 6.1.d.2 of the Enforcement Policy dated January 15, 2020, because the violation resulted in a condition which was previously evaluated as having very low safety significance (i.e., Green) as discussed in the subject inspection report. Because you initiated condition reports demonstrating objective evidence of plans to restore compliance, the violation is being treated as a Non-Cited Violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy. The Enforcement Policy is included on the NRCs Web site at (http://www.nrc.gov/about-nrc/regulatory/enforcement/enforce-pol.html).
In the letter transmitting Inspection Report 2020012, we provided Exelon with the opportunity to address the apparent violation identified in the report by either attending a pre-decisional enforcement conference or by providing a written response before we made our final enforcement decision. Although Exelon provided a response to the apparent violation in a letter dated July 2, 2020, "Response to Apparent Violation in NRC Inspection Report 05000237/2020012 and 05000249/2020012; EA-20-053," (ML20184A260) the NRC did not use the information in the letter to make its final enforcement decision. As stated above, the NRC made its final enforcement decision solely based upon example 6.1.d.2 of the Enforcement Policy.
However, while reviewing the information submitted by Exelon, the NRC identified that 10 CFR 50.59 Evaluation 2020-02-001, Update to UFSAR Section 9.2.5.3.1, DOA 0010-01, and DTS 4450-04, Revision 1, did not consider the plants original design and licensing basis:
a loss of the dam due to a seismic event coincident with a loss of offsite power (LOOP).
Region III inspectors reviewed the design and licensing basis of the facility and consulted with the Division of Reactor Oversight in the Office of Nuclear Reactor Regulation to determine if a seismically induced dam failure coincident with a LOOP was originally part of the design and licensing basis for Dresden Station. The NRC will follow up on this issue of concern using either Inspection Procedure 92702, Follow-up on Traditional Enforcement Actions Including Violations, Deviations, Confirmatory Action Letters, Confirmatory Orders, and Alternative Dispute Resolution Confirmatory Orders, or another baseline inspection effort.
If you contest the violation or the severity of the violation documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region III; the Director, Office of Enforcement; and the NRC Resident Inspector at Dresden Nuclear Power Station, Units 2 and 3.
This letter, its enclosure, and your response, if you choose to provide one, will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding. To the extent possible, your response should not include any personal privacy or proprietary information so that it can be made available to the Public without redaction.
Sincerely, David Curtis, Deputy Director Division of Reactor Safety Docket Nos. 05000237 and 05000249 License Nos. DPR-19 and DPR-25
Enclosure:
As stated
Inspection Report
Docket Numbers: 05000237 and 05000249 License Numbers: DPR-19 and DPR-25 Report Numbers: 05000237/2020090 and 05000249/2020090 Enterprise Identifier: I-2020-090-0006 Licensee: Exelon Generation Company, LLC Facility: Dresden Nuclear Power Station, Units 2 and 3 Location: Morris, IL Inspection Dates: July 01, 2020 to September 28, 2020 Inspectors: J. Corujo-Sandin, Senior Reactor Inspector L. Rodriguez, Operations Engineer Approved By: David Curtis, Deputy Director Division of Reactor Safety Enclosure
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting an NRC inspection at Dresden Nuclear Power Station, Units 2 and 3, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations
Failure to Have Appropriate Evaluation to Support a Change to the Required Ultimate Heat Sink Coping Time and Capacity Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None 71111.07T Systems NCV 05000237,05000249/2020012-02 Closed EA-20-053 The inspectors identified a non-cited violation of 10 CFR 50.59, "Changes, Tests, and Experiments," for the licensee's failure to have a written evaluation which provided the bases for determining a change made pursuant to 10 CFR 50.59(c) did not require a license amendment. Specifically, the licensee approved a change to the Updated Final Safety Analysis Report (UFSAR) which reduced the ultimate heat sink coping time and capacity from four days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The licensee failed to provide a basis for the determination that the change would not result in more than a minimal increase in the likelihood of occurrence of a malfunction of the diesel generator cooling water system previously evaluated in the UFSAR.
Additional Tracking Items
None.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
REACTOR SAFETY
71111.07T - Heat Sink Performance Triennial Review (IP Section 03.02)
The inspectors reviewed information submitted by the licensee on July 2, 2020 associated with apparent violation 05000237/2020012-02; 05000249/2020012-02.
INSPECTION RESULTS
Failure to Have Appropriate Evaluation to Support a Change to the Required Ultimate Heat Sink Coping Time and Capacity Cornerstone Significance/Severity Cross-Cutting Report Aspect Section Mitigating Green None 71111.07T Systems Severity Level IV NCV 05000237,05000249/2020012-02 Closed EA-20-053 The inspectors identified a non-cited violation of 10 CFR 50.59, "Changes, Tests, and Experiments," for the licensee's failure to have a written evaluation which provided the bases for determining a change made pursuant to 10 CFR 50.59(c) did not require a license amendment. Specifically, the licensee approved a change to the Updated Final Safety Analysis Report (UFSAR) which reduced the ultimate heat sink coping time and capacity from four days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The licensee failed to provide a basis for the determination that the change would not result in more than a minimal increase in the likelihood of occurrence of a malfunction of the diesel generator cooling water system previously evaluated in the UFSAR.
Description:
On April 24, 2020, the NRC completed a triennial heat sink inspection at Dresden Nuclear Power Station. As discussed in NRC Inspection Report 05000237/2020012; 05000249/2020012, the NRC documented an apparent violation of 10 CFR 50.59 due to the licensee's failure to have a written evaluation providing a bases for determining a change to the ultimate heat sink coping time and capacity did not result in more than a minimal increase in the likelihood of occurrence of a malfunction of the diesel generator cooling water system. Inspection Report 05000237/2020012; 05000249/2020012 can be found in the NRC's Agencywide Document Access and Management System (ADAMS) at Accession No. ML20140A181.
In the letter transmitting Inspection Report 2020012, the NRC provided Exelon with an opportunity to address the apparent violation described in the report by either attending a pre-decisional enforcement conference or by providing a written prior to the Agency made its final enforcement decision. Exelon provided a written response to the NRC regarding the apparent violation on July 2, 2020 (ML20184A260). The NRC did not use the information provided by the licensee to make its final enforcement decision. Instead, the NRC determined the apparent violation described in Inspection Report 05000237/2020012; 05000249/2020012 (AV 05000237;05000249/2020012-02) was best characterized as a Severity Level IV violation of NRC requirements based upon example 6.1.d.2 of the NRC's Enforcement Policy dated January 15, 2020, because the violation resulted in a condition which was previously evaluated as having very low safety significance (i.e., Green) in the subject inspection report. Because the licensee initiated condition reports demonstrating objective evidence of plans to restore compliance during the triennial heat sink inspection, the NRC also decided to treat this Severity Level IV violation as a non-cited violation consistent with Section 2.3.2 of the NRC Enforcement Policy.
Corrective Actions: The licensee captured the inspectors concerns in Corrective Action Program documents referenced below. The licensee evaluated the current ultimate Heat Sink (UHS) capability and demonstrated the UHS could be replenished before the operability and/or functionality of the Diesel Generator Cooling Water (DGCW) system, and other important to safety systems, would be impacted by the deficiencies described previously.
Corrective Action References: AR 4322375, "2020 NRC UHS Inspection: UFSAR Revision UHS Volume" AR 4323025, "2020 UHS Inspection - IR 2533713 Action not Complete" AR 4325402, "Timber Mat Contact" AR 4343358, "2020 UHS Inspection - 50.59 Apparent Violation"
Performance Assessment:
Performance Deficiency: The license failed to have a written evaluation which provided the bases for determining a change to the UHS capacity and coping time would not result in more than a minimal increase in the likelihood of occurrence of a malfunction of the DGCW system and did not require a license amendment. This is contrary to 10 CFR 50.59, "Changes, Tests and Experiments," and was a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because it was associated with the Design Control attribute of the Mitigating Systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the licensee made a change to the UHS capacity and coping time without having an evaluation which demonstrated this change would not result in a more than minimal increase in the likelihood of occurrence of a malfunction of structures, systems or components important to safety previously evaluated in the final safety analysis report.
Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The inspectors determined this finding is of very low safety significance (Green) because the ultimate heat sink and the diesel generator cooling water system maintained their operability and probabilistic risk assessment functionality.
Cross-Cutting Aspect: None
Enforcement:
The ROPs significance determination process does not specifically consider the regulatory process impact in its assessment of licensee performance. Therefore, it is necessary to address this violation which impedes the NRCs ability to regulate using traditional enforcement to adequately deter non-compliance.
Severity: In accordance with example 6.1.d.2 of the Enforcement Policy dated January 15, 2020, this violation is categorized as a Severity Level IV because it resulted in a condition evaluated as having very low safety significance (i.e., Green) by the SDP.
Violation: Title 10 CFR 50.59, "Changes, Test, and Experiments," Section (d)(1) requires the licensee to maintain records of changes in the facility, of changes in procedures, and of tests and experiments made pursuant 10 CFR 50.59(c). These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license amendment pursuant to paragraph (c)(2) of this section. Title 10 CFR 50.59(c)(2)(ii) states, in part, that a licensee shall obtain a license amendment pursuant to 10 CFR 50.90 prior to implementing a proposed change, test, or experiment if the change, test, or experiment would result in more than a minimal increase in the likelihood of occurrence of a malfunction of a structure, system or component (SSC)important to safety previously evaluated in the final safety analysis report (as updated).
Section 9.2.5.3.1 of the final safety analysis report (as updated) stated that only the part of the intake canal trapped inventory above the suction of the diesel generator cooling water pumps (2 million gallons) is considered available from the UHS, as the makeup path potentially relies on on-site power. This inventory lasts approximately four days following extended power uprate. If the off-site power is restored within the 4-day period, the time would increase because the entire volume of the intake canal would be available with no diesel generator cooling required.
Contrary to the above, since October 17, 2019, to the present, the license failed to maintain a record of a change to the facility that included a written evaluation which provided the bases for determining the change made pursuant to 10 CFR 50.59(c) did not require a license amendment. Specifically, on October 17, 2019, the licensee approved a change to the UFSAR via 50.59 Screening 2019-134 that changed the coping time of the UHS from four days to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The screening, nor the subsequent written evaluation documented by 10 CFR 50.59 Evaluation 2020-02-001 on February 17, 2020, provided a basis for the determination that the change would not result in more than a minimal increase in the likelihood of occurrence of a malfunction of an SSC important to safety previously evaluated in the final safety analysis report (as updated). Specifically, the licensee did not have a written evaluation that demonstrated there was no more than a minimal increase in the likelihood of occurrence of a malfunction of the DGCW system given the change to the required UHS capacity.
Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
x On September 28, 2020, the inspectors presented the NRC inspection results to Mr. R. Sprengel, Regulatory Assurance Manager and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision or
Procedure Date
71111.07T Calculations DRE16-0011 Required Ultimate Heat Sink (UHS) Capacity 1
Corrective Action AR 4343358 2020 UHS Inspection - 50.59 Apparent Violation 05/19/2020
Documents AR 4384954 50.59 Basis Clarification 11/17/2020
Resulting from
Inspection
Drawings M-194 Outdoor Piping U
M-355 Diagram of Service Water Piping SQ
M-52 Circulating Water Piping Plan K
M-53 Circulating Water Piping Sections K
Engineering 631940 Determination of the Volume of Water Contained in Piping 0
Changes Between the Condenser and the Circ Pumps for a Loss of
Dam Event
DFL 12-007 UFSAR Change 12-007 0
Engineering 2012-0067 UFSAR Changes Related to Loss of Dam 0
Evaluations 2020-02-001 Update to UFSAR Section 9.2.5.3.1, DOA 0010-01, and 1
DTS 4450-04
Miscellaneous Amendment Nos. 9 and 10 to the Applications for Construction 02/28/1969
Permits and Operating Licenses for Dresden Units 2 and 3
Filed Under AEC Dkts 50-237 and 50-249, Respectively
RS-01-208 Additional Information Supporting the License Amendment 09/26/2001
Request to Permit Uprated Power Operation at Dresden
Nuclear Power Station
SVPLTR 20-0037 Response to Apparent Violation in NRC Inspection Report 07/02/2020
05000237/2020012 and 05000249/2020012; EA-20-053
Procedures DGA-12 Loss of Offsite Power 80
DOA 0010-01 Dresden Lock and Dam Failure 37
DOP 1300-03 Manual Operation of the Isolation Condenser 38
DTS 4450-04 Dresden Credited Ultimate Heat Sink Bathymetric Surveillance 2
for Intake and Discharge Canals
7