IR 05000454/2018010

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Closure of Auxiliary Feedwater System Unresolved Item 05000454/2018010-04 and 05000455/2018010-04
ML21081A152
Person / Time
Site: Byron  Constellation icon.png
Issue date: 03/19/2021
From: Karla Stoedter
NRC/RGN-III/DRS/EB2
To: Rhoades D
Exelon Generation Co, Exelon Nuclear
Shared Package
ML21081A138 List:
References
IR 2018010
Download: ML21081A152 (8)
v • d • e


Text

March 19, 2021

SUBJECT:

BYRON STATION - CLOSURE OF AUXILIARY FEEDWATER SYSTEM UNRESOLVED ITEM 05000454/2018010-04 AND 05000455/2018010-04

Dear Mr. Rhoades:

On December 4, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Byron Station and discussed the results of this inspection with Mr. K. McGuire and other members of your staff. The results of this inspection are documented in the enclosed report.

No findings or violations of more than minor significance were identified during this inspection.

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,

/RA/

Karla K. Stoedter, Chief Engineering Branch 2 Division of Reactor Safety Docket Nos. 05000454 and 05000455 License Nos. NPF-37 and NPF-66

Enclosure:

As stated

Inspection Report

Docket Numbers: 05000454 and 05000455 License Numbers: NPF-37 and NPF-66 Report Numbers: 05000454/2020010 and 05000455/2020010 Enterprise Identifier: I-2020-010-0055 Licensee: Exelon Generation Company, LLC Facility: Byron Station Location: Byron, IL Inspection Dates: April 13, 2020 to December 04, 2020 Inspectors: E. Sanchez Santiago, Senior Reactor Inspector Approved By: Karla K. Stoedter, Chief Engineering Branch 2 Division of Reactor Safety Enclosure

SUMMARY

The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a design basis assurance inspection (teams) inspection at Byron Station, 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

No findings or violations of more than minor significance were identified.

Additional Tracking Items

Type Issue Number Title Report Section Status URI 05000454, Use of 10 CFR 50.54(x) for 71111.21M Closed 05000455/2018010-04 Unit AFW Cross-Tie

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.

INSPECTION RESULTS

Unresolved Item Use of 10 CFR 50.54(x) for Unit AFW Cross-Tie 71111.21M (Closed) URI 05000454,05000455/2018010-04

Description:

In 2008, the licensee added steps to Emergency Operating Procedure (EOP)1/2BFR-H.1, Response to Loss of Secondary Heat Sink, to use the motor-driven auxiliary feedwater (MDAFW) train of a non-accident unit to combat a loss of all feedwater event in the opposite unit by using a recently installed unit cross-tie. The EOPs also directed operators to enter the technical specification limiting condition for operation action statement for the unit donating the MDAFW train because the MDAFW trains were not licensed to be shared between the reactor units.

In 2011, the resident inspectors documented a Severity Level IV non-cited violation (NCV) of 10 CFR 50.59 after determining the licensees 2008 EOP change resulted in more than a minimal increase in the likelihood of occurrence of a malfunction of a structure, system or component important to safety. Specifically, the Updated Final Safety Analysis Report described the auxiliary feedwater (AF) trains as non-shared systems. This violation was documented in Inspection Report 05000454/2011004; 05000455/2011004 as NCV 05000454/2011004-02; 05000455/2011004-02, Modification of the Auxiliary Feedwater System Without Prior NRC Approval (REF: ADAMS Accession No. ML113070678).

As a corrective action to this NCV, the licensee removed the steps in EOP 1/2BFR-H.1, "Response to Loss of Heat Sink," that directed the unit cross-tie to be used and removed credit for the cross-tie in the stations Probabilistic Risk Assessment model. On August 8, 2017, the licensee added direction in EOP 1/2BFR-H.1 to use the AF cross-tie by invoking 10 CFR 50.54(x). The procedure change included a note which stated, If at any time it has been determined that restoration of feed flow to any SG [steam generator] is untimely or may be ineffective in heat sink restoration, then the AF crosstie should be implemented per Step 5 (Page 8). The licensee also added a caution which stated, The AF crosstie should be implemented per Step 5 if other attempts to restore feed flow to the SG(s) will not prevent the initiation of feed and bleed. The DBAI team was concerned the note and caution provided direction to initiate the AF unit cross-tie before bleed and feed, rather than the instruction being provided in the actual procedure step.

During the 2018 design basis assurance inspection, the inspectors initiated an unresolved item to document their concerns associated with the licensees actions in response to the 2011 SLIV NCV. Specifically, the inspectors challenged the use of 10 CFR 50.54(x) to implement this change. In addition, the inspectors noted that the licensees 10 CFR 50.59 screening for the procedure change did not include or evaluate the aforementioned note and caution statements to determine whether the 2017 EOP change required prior NRC approval via a license amendment.

Since 2018, the NRC has evaluated the details associated with the above concerns, engaged NRC staff experts, and reviewed licensee procedures and owners group documents related to the technical aspects of the issue to determine whether a performance deficiency or violation occurred. Based on this review, the inspectors did not identify a performance deficiency or violation of requirements.

Specifically, regarding the concern the licensee used 10 CFR 50.54(x) to implement a permanent change, the inspector concluded the 2017 EOP revision which added the note, caution and the step for implementing the AF cross-tie by invoking 10 CFR 50.54(x) did not constitute a change as defined in 10 CFR 50.59, Changes, tests and experiments. Title 10 CFR 50.59 defines change as, a modification or addition to, or removal from, the facility or procedure that affects a design function, method of performing or controlling the function, or an evaluation that demonstrated that intended functions will be accomplished. Also, NEI 96-07, Section 1.2.4, Relationship of 10 CFR 50.59 to 10 CFR 50.2 Design Bases, states, 10 CFR 50.59 controls changes to both 10 CFR 50.2 design basis and supporting design information contained in the Updated Final Safety Analysis Report. The AF cross-tie would be implemented during beyond design basis events and would require invoking 10 CFR 50.54(x), therefore the change falls outside the site's licensing and design basis.

The inspectors also reviewed the URI concern:

(1) the added note and caution were the only procedure provisions that provided direction on when to use the MDAFW cross-tie; and (2)those procedure provisions were not included in the 10 CFR 50.59 screening. Per the above discussion, the inspectors concluded the change did not fall under the requirements of 10 CFR 50.59. Regarding the caution statement providing direction, the inspectors noted that the caution includes a should statement which per procedure AD-AA-101-1002, Writers Guide for Procedures and T&RM, denotes a management expectation but does not require or direct a specific action. When the licensee was questioned on the purpose of the caution statement, they indicated it was to let the operators know the AF cross-tie should be implemented after all other options are exhausted and feed and bleed was the only remaining alternative. The licensee also stated that per EOP 1/2BFR-H.1, Step 2, "Check if Bleed and Feed is Required," if the criteria described in the procedure for initiating feed and bleed are met, the licensed operators would be required to implement the bleed and feed actions.

There is no allowance to bypass actions related to initiating bleed and feed, once the criteria are met. The licensee also stated the bleed and feed actions would not be delayed to allow implementation of the AF cross-tie. Per the licensee, the added note and caution did not require the use of the cross-tie prior to implementing feed and bleed. Step 5 of procedure 1/2BFR-H.1, "Crosstie Train A AF From Unit 1/2," stated, "Shift Manager has: Determined other heat sink restoration efforts are not available or are untimely; Has implemented 10 CFR 50.54(x); Approved implementation of 1BFSG-3, Alternate Low Pressure Feedwater for AF crosstie." Based on these instructions, the decision to invoke 10 CFR 50.54(x) and implement the cross-tie would be made by the shift manager. The caution also served the purpose of informing the operators that the implementation of the AF cross-tie would require invoking 10 CFR 50.54(x). Per procedure AD-AA-101-1002, one of the purposes of a caution statement is to alert personnel of violations of rules, regulations or work practices. Therefore, the inspectors did not identify a performance deficiency associated with these actions.

EXIT MEETINGS AND DEBRIEFS

The inspectors verified no proprietary information was retained or documented in this report.

DOCUMENTS REVIEWED

Inspection Type Designation Description or Title Revision or

Procedure Date

71111.21M Engineering 362168 Installation of the Final Phase of the Motor-Driven Auxiliary 0

Changes Feedwater Pump Crosstie Line between Units 1&2

Miscellaneous Email AFW Issue - 5054x Licensees_BGH.docx 08/28/2019

Federal Register Applicability of License; Conditions and Technical 04/01/1983

Vol. 48, No. 64 Specifications in an Emergency

ML043440415 Letter to A. Scherer (Southern California Edison) from 02/05/1999

J. Moore (NRC)

NEI 96-07 Guidelines for 10 CFR 50.59 Implementation 1

Procedures 1BFR-H.1 Response to Loss of Secondary Heat Sink 300

AD-AA-101-1002 Writer's Guide for Procedures and T&RM 18

6

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