IR 05000237/2021011
| ML21273A170 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/30/2021 |
| From: | Richard Skokowski Engineering Branch 3 |
| To: | Rhoades D Exelon Generation Co |
| References | |
| IR 2021011 | |
| Download: ML21273A170 (11) | |
Text
September 30, 2021
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - TRIENNIAL FIRE PROTECTION INSPECTION REPORT 05000237/2021011 AND 05000249/2021011
Dear Mr. Rhoades:
On August 26, 2021, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Dresden Nuclear Power Station, Units 2 and 3 and discussed the results of this inspection with Mr. P. Boyle, Plant Manager and other members of your staff. The results of this inspection are documented in the enclosed report.
One finding of very low safety significance (Green) is documented in this report. This finding did not involve a violation of NRC requirements.
If you disagree with a cross-cutting aspect assignment or a finding not associated with a regulatory requirement in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region III; and the NRC Resident Inspector at Dresden Nuclear Power Station, Units 2 and 3. This letter, its enclosure, and your response (if any) 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.
Sincerely, Stoedter, Karla signing on behalf of Skokowski, Richard on 09/30/21 Richard A. Skokowski, Chief Engineering Branch 3 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: 05000237/2021011 and 05000249/2021011 Enterprise Identifier: I-2021-011-0046 Licensee: Exelon Generation Co., LLC Facility: Dresden Nuclear Power Station, Units 2 and 3 Location: Morris, IL Inspection Dates: July 12, 2021 to August 26, 2021 Inspectors: J. Benjamin, Senior Reactor Inspector A. Dahbur, Senior Reactor Inspector B. Jose, Senior Reactor Inspector Approved By: Richard A. Skokowski, Chief Engineering Branch 3 Division of Reactor Safety Enclosure
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a triennial fire protection 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 Perform Quality Review for NRC Information Notice 2017-06 Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [H.14] - 71111.21N.
Systems FIN 05000237,05000249/2021011-01 Conservative 05 Open/Closed Bias The inspectors identified a finding (FIN) of very low safety significance (Green) that was not associated with a violation for the licensees failure to perform a quality review for level 3 Operating Experience (OPEX) as specified in Exelon Generation Procedure PI-AA-115-1003,
Processing of Level 3 OPEX Evaluation. Specifically, the licensee failed to perform a quality review for NRC Information Notice (IN) 2017-06, "Battery and Battery Charger Short-Circuit Current Contributions to a fault on the Direct Current (DC) Distribution System," to ensure the documentation in the OPEX evaluation was a stand-alone document and clear enough to identify that the review was completed satisfactorily.
Additional Tracking Items
Type Issue Number Title Report Section Status URI 05000237,05000249/ Potential Non-Conservative 71111.21N.05 Closed 2021010-02 DC Short-Circuit Current Values
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.
Starting on March 20, 2020, in response to the National Emergency declared by the President of the United States on the public health risks of the coronavirus (COVID-19), inspectors were directed to begin telework. In addition, regional baseline inspections were evaluated to determine if all or a portion of the objectives and requirements stated in the IP could be performed remotely. If the inspections could be performed remotely, they were conducted per the applicable IP. In some cases, portions of an IP were completed remotely and on site. The inspections documented below met the objectives and requirements for completion of the IP.
REACTOR SAFETY
71111.21N.05 - Fire Protection Team Inspection (FPTI) Structures, Systems, and Components (SSCs) Credited for Fire Prevention, Detection, Suppression, or Post-Fire Safe Shutdown Review (IP Section 03.01)
The inspectors verified that components and/or systems will function as required to support the credited functions stated for each sample. Additional inspection considerations are located in the fire hazards analysis (FHA) or safe shutdown analysis (SSA).
- (1) Fire detection and suppression systems for Fire Zone 8.2.8.A (Turbine Building EL 561 - 6 Main Operating Floor)
- (3) Unit 2 Control Rod Drive (CRD) Pump
- (4) Unit 2/3 Diesel Driven Fire Pump
Fire Protection Program Administrative Controls (IP Section 03.02) (2 Samples)
The inspectors verified that the selected control or process is implemented in accordance with the licensees current licensing basis. If applicable, the inspectors also ensured the licensees FPP contains adequate procedures to implement the selected administrative control. Lastly, the inspectors verified the selected administrative control met the requirements of all committed industry standards.
- (1) Combustible Control Program
- (2) Fire System Impairments
Fire Protection Program Changes/Modifications (IP Section 03.03) (2 Samples)
The inspectors verified the following:
a. Changes to the approved FPP did not constitute an adverse effect on the ability to safely shutdown.
b. The adequacy of the design modification, if applicable.
c. Assumptions and performance capability stated in the SSA have not been degraded through changes or modifications.
d. The FPP documents, such as the Updated Final Safety Analysis Report, fire protection report, FHA, and SSA were updated consistent with the FPP or design change.
e. Post-fire SSD operating procedures, such as abnormal operating procedures, affected by the modification were updated.
- (1) Engineering Change (EC) 630156; Technical Evaluation to Justify Adequate Fire Suppression Coverage with Failed Sprinkler Heads in the Turbine Building Mezzanine Area
INSPECTION RESULTS
Failure to Perform Quality Review for NRC Information Notice 2017-06 Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [H.14] - 71111.21N.0 Systems FIN 05000237,05000249/2021011-01 Conservative 5 Open/Closed Bias The inspectors identified a finding (FIN) of very low safety significance (Green) that was not associated with a violation for the licensees failure to perform a quality review for level 3 Operating Experience (OPEX) as specified in Exelon Generation Procedure PI-AA-115-1003, Processing of Level 3 OPEX Evaluation. Specifically, the licensee failed to perform a quality review for NRC Information Notice (IN) 2017-06, "Battery and Battery Charger Short-Circuit Current Contributions to a fault on the Direct Current (DC) Distribution System,"
to ensure the documentation in the OPEX evaluation was a stand-alone document and clear enough to identify that the review was completed satisfactorily.
Description:
During the Design Basis Assurance Team Inspection completed on January 29, 2021, NRC inspectors identified an Unresolved Item (URI) which could not be resolved without additional information. This issue was associated with the licensees failure to perform an adequate evaluation for NRC Information Notice (IN) 2017-06. Specifically, the Dresden 125 Vdc and 250 Vdc battery chargers were silicon-controlled rectifier (SCR) type battery chargers, and the testing described in the IN demonstrated SCR-type battery chargers produced significantly higher currents than expected. The inspectors planned to keep the URI open pending a review of the licensees updated evaluation of NRC IN 2017-06, which was being tracked by Action Request (AR) 4398306, and a determination of whether any performance deficiencies or violations of NRC requirements had occurred.
Following the Design Basis Assurance Inspection, the licensee generated EC 633645, Dresden Information Notice 2017-06 Evaluation, to evaluate whether equipment at Dresden Station was susceptible to experiencing potentially high fault current contributions as described in IN 2017-06. The licensee concluded there were no operability or station equipment vulnerability concerns at Dresden related to IN 2017-06.
The inspectors reviewed the licensee's evaluation and associated calculations and did not identify any technical concerns. In addition, the inspectors reviewed the battery chargers internal fuse characteristics and coordination with the downstream protective devices and did not identify any concerns.
Section 4.6, Quality Review, of Exelon Generation Procedure PI-AA-115-1003, Processing of Level 3 OPEX Evaluation, directed a quality review be performed to ensure the documentation in the OPEX evaluation is a stand-alone document and is clear enough to identify that the review was completed satisfactorily. The inspectors determined the licensee's initial Level 3 OPEX evaluation for IN 2017-006 did not meet the licensee's standard for a Level 3 OPEX review because the evaluation was not stand-alone and was not clear enough to identify the review was completed satisfactorily. Specifically, the licensee's initial OPEX review did not demonstrate why the site was not vulnerable to the situation described in IN 2017-06 nor did it provide information to demonstrate that the station equipment would be able to withstand the larger short circuit conditions provided by the chargers as described in the IN. The licensees failure to perform a proper/complete review of the Level 3 OPEX evaluation for IN 2017-006 was contrary to the Exelon Procedure PI-AA-115-1003 and was a performance deficiency. No violations of NRC requirements were identified since this procedure was not safety-related and therefore, not subject to 10 CFR Part 50 Appendix B requirements.
Corrective Actions: The licensee revised the Level 3 OPEX evaluation for IN 2017-06 and concluded the larger short circuit current contribution from the charger did not exceed the interrupting ratings of equipment/isolation devices.
Corrective Action References: AR 4398306 - 2021 DBAI: OPEX IN 17-06 Evaluation Incomplete
Performance Assessment:
Performance Deficiency: The inspectors determined the licensees failure to perform a proper Level 3 OPEX evaluation for IN 2017-06 was contrary to Exelon Generation Procedure PI-AA-115-1003, Processing of Level 3 OPEX Evaluation. Specifically, the licensee failed to ensure the documentation in the OPEX evaluation was stand-alone and clear enough to identify the review was completed satisfactorily. Specifically, OPEX evaluation 4067133-02 failed to demonstrate why the site was not vulnerable to the situation described in the IN nor did it provide information to demonstrate station equipment would be able to withstand the larger short circuit conditions provided by the chargers as described in the Information Notice.
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, regardless of the results of the final/revised evaluation, the failure to perform proper Level 3 OPEX evaluation for NRC IN 2017-06 resulted in a condition where there was a reasonable doubt that equipment/isolation devices were able to withstand the larger short circuit conditions provided by the chargers as described in the IN.
Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The finding screened as of very low safety significance (Green) because it did not result in the loss of operability or functionality of mitigating systems. Specifically, the licensee revised the IN 2017-06 evaluation and were able to show that equipment/isolation devices were capable to withstand the available short circuit current.
Cross-Cutting Aspect: H.14 - Conservative Bias: Individuals use decision making-practices that emphasize prudent choices over those that are simply allowable. A proposed action is determined to be safe in order to proceed, rather than unsafe in order to stop. Specifically, the licensee's initial evaluation for IN 2017-06 failed to evaluate the effect of the larger short current contribution from the charger on the interrupting rating of the equipment/isolation devices. Instead, the licensee only verified that the short circuit current as specified in the existing calculation did not exceed the plant equipment/isolation devices interrupting rating.
Enforcement:
Inspectors did not identify a violation of regulatory requirements associated with this finding.
The disposition of this finding closes URI: 05000237,05000249/2021010-02 URI Potential Non-Conservative DC Short-Circuit Current 71111.21N.
Values 05 URI 05000237,05000249/2021010-02
Description:
A finding of very low risk significance (Green) was identified in Section 71111.21N.05 of this report as described previously.
Corrective Action Reference(s): AR 4398306: 2021 DBAI: OPEX IN 17-06 Evaluation Incomplete AR 4056647: OPEX Review: IN 2017-06: Battery / Charger Short Circuits (Corporate AR)
AR 4399797: AR Generated to Determine Course of Action for 2021 DBAI: OPEX IN 17-06 Evaluation (Corporate AR)
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
On August 26, 2021, the inspectors presented the triennial fire protection inspection results to Mr. P. Boyle, Plant Manager and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision or
Procedure Date
71111.21N.05 Calculations 001-92-125 Hydraulic Analysis of the Dresden Station Unit 2/3 0
Cribhouse Fire Suppression System APPR 10 for the
Commonwealth Edison Company
DRE98-0023 Diesel Fire Pump Test Acceptance Criteria 0
Corrective Action AR 02534794 2/3 Diesel Fire Pump (DFP) Failed to Start 07/29/2015
Documents Troubleshooting
AR 04142256 2/3 DFP Surveillance in Progress, Bad Data 05/29/2018
Corrective Action AR 04435124 Evaluate Locking Open Unit 1 DFP Valve 07/15/2021
Documents AR 04435186 Revise FPR to Reflect CRD Crosstie Configuration 07/15/2021
Resulting from AR 04436168 Typo in DFPS 4123-06 07/21/2021
Inspection AR 04436461 DFPS 4123-05 Needs Revision 07/22/2021
AR 04437037 Minimum Battery Resistance Procedure Enhancement 07/26/2021
AR 04437341 Intervening Combustible with no Firewrap 07/27/2021
AR 04440577 Actions in Response to FP Inspection NRC Challenges 08/13/2021
AR 04440577 Action Response to FP Inspection NRC Challenge 08/13/2021
Drawings F-16-1 Detection and Suppression Turbine Building Main Floor 1
F-17-1 Detection and Suppression Turbine Building Main Floor 1
(Unit 3)
F-9-1 Detection and Suppression Turbine Building Basement C
M-23 Diagram Fire Protection Piping AT
M-34 Diagram of Control Rod Drive Hydraulic Piping E133
Engineering EC 357368 Install Alternate Service Water Pipe-Outdoor Portion 11/02/2009
Changes EC 630156 Engineering Technical Evaluation to Justify Adequate Fire 01/21/2020
Suppression Coverage with Failed Sprinkler Head in the
TB Mezz Area
EC 633431 Evaluation of High Pressure Drop Noted During Fire 04/20/2021
Protection Yard Loop Flow Surveillance
Engineering EC 630156 Justify Adequate Fire Suppression Coverage with Failed 0
Evaluations Sprinkler Heads in TB Mezz Area
Procedures 155 U2TB-57 FZ 8.2.8A Unit 2 Main Turbine Floor Elevation 561 3
CC-AA-206 Fuse Control 11
Inspection Type Designation Description or Title Revision or
Procedure Date
DEOP 0100-00 RPV Control 13
DFPP 4175-01 Fire Barrier Integrity and Maintenance 24
DFPS 4123-06 Figure 2 2/3 DFP Performance Chart, Manufacturer's 50
Pump Curve
DFPS 4175-02 Operating Fire Break/Stop Surveillance 34
DGP 02-03 Reactor Scram 117
DOA 0010-10 Fire/Explosion 26
IR 4364390 NOS ID: Operator Response Time Docs not Archivied in 08/20/2020
MA-AA-723-325 Molded Case Circuit Breaker Testing 19
PI-AA-115-1003 Processing of Level 3 OPEX Evaluation 5
Work Orders 4741434 D2 EFL AD Locked Valve Surv 11/06/2019
5109375 IST Control Rod Drive Exercise 03/05/2021
5138844 IST Control Rod Drive Exercise 05/21/2021
WO 4645566 D2/3 an TSTR/Com Diesel Fire Pump Flow Capacity Test 08/17/2018
WO 4832450 D2/3 18M TSTR/Com Diesel Fire Pump Flow Capacity 03/03/2020
Test
8