RBG-47896, Response to NRC Baseline Inspection Report 05000458/2018012

From kanterella
Jump to navigation Jump to search
Response to NRC Baseline Inspection Report 05000458/2018012
ML18235A636
Person / Time
Site: River Bend Entergy icon.png
Issue date: 08/23/2018
From: Schenk T
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation, NRC Region 4
References
IR 2018012, RBG-47896 IR 2018012-05
Download: ML18235A636 (12)
v • d • e


Text

  • Entergy.

-c::::-

Entergy Operations, Inc.

River Bend Station 5485 U.S Highway 61 N Sl. Francisville. LA 70775 Tel 225-381-4177 Timothy Schenk Manager - Regulatory Assurance RBG-47896 August 23, 2018 U.S. Nuclear Regulatory Commission ATTN : Document Control Desk Washington , DC 20555-0001

SUBJECT:

Response to NRC Baseline Inspection Report 05000458/2018012 River Bend Station , Unit 1 Docket No. 50-458 License No. NPF-47

References:

Letter from Jason W. Kozal to William F. Maguire, NRC Baseline Inspection Report 05000458/2018012 (ML18194A413)

RBF1-18-0169

Dear Sir or Madam :

The purpose of this letter is to provide Entergy, River Bend Station 's response to the following Non-Cited Violations (NCV's) given in the subject report

The due date for this response to the subject letter was extended from 8/18/2018 to 8/24/2018 after verbal approval from Jason Kozal on 8/14/2018 .

There are no regulatory commitments contained in this submittal. If you require additional information, please contact Mr. Tim Schenk at (225)-381 -4177 or tschenk@entergy.com .

Sincere;r~

TASldjp

_ * ' C_ ... -C~,.ff.l"'.r-"-

RBG-47896 Page 2 of 2 : Basis for Denial of NCV 05000458/2018012-05: "Failure to Develop an Adequate Operational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the Feedwater System Sparger Nozzles" Example 2 : Basis for Denial of NCV 05000458/2018012-07: "Failure to Perform 10 CFR 50.59 Evaluation for Main Feedwater System Sparger Nozzle Damage" cc: U.S . Nuclear Regulatory Commission , Region IV ATTN: Kriss M. Kennedy, Regional Administrator ATTN : Michael C. Hay, Team Leader Allegations Coordination and Enforcement Staff 1600 E. Lamar Blvd.

Arlington , TX 76011-4511 NRC Senior Resident Inspector, River Bend Station Attn : Mr. Jeff Sowa 5485 U.S. Highway 61 , Ste. NRC St. Francisville, LA 70775

ATTACHMENT 1 Basis for Denial of NCV 05000458/2018012-05 :

"Failure to Develop an Adequate Operational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the Feedwater System Sparger Nozzles" Example 2

ATTACHMENT 1 Basis for Denial of NCV 05000458/2018012-05 :

"Failure to Develop an Adequate Operational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the Feedwater System Sparger Nozzles" Example 2 Summary of Violation In reference to the NRC Letter dated July 18, 2018, "River Bend Station - NRC Baseline Inspection Report 05000458/201812 (ML18194A13), the U.S. Nuclear Regulatory Commission (NRC) identified a Green Non-Cited Violation (NCV 05000458/2018012-05) for Failure to Develop an Adequate Operational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the Feedwater System Sparger Nozzles. The violation summary states:

The inspectors identified a Green NCV of 10 CFR Part 50, Appendix B, Criterion V, "Instructions, Procedures, and Drawings," for the failure to develop an adequate operational decision-making issue (ODMI) document per Procedure EN-OP-111 ,

"Operational Decision-Making Issue Process." Specifically, the licensee failed to develop an ODMI that provided adequate guidance to the operators for safely operating the plant with degraded feedwater sparger nozzles.

Based on a detailed review of applicable NRC regulations and NRC guidance documents, relative to the documents reviewed by the NRC inspectors during the Baseline Inspection ,

Entergy Operations, Inc. (EOI) respectfully disagrees with the NRC's assessment and conclusions for NCV 05000458/2018012-05 Example 2.

Entergy's Position Entergy accepts the subject violation but believes that Example 2 should be removed from the violation . The method used by RBS to establish the monitoring trigger points was consistent with the RBS licensing and design basis methodology as described in the General Electric setpoint methodology in NEDC -31336P-A as approved by the NRC in SER November 6,1995.

The treatment of uncertainties and calculation of setpoints, including allowable values , was consistent with RG1 .105 and ISA 67.04 1994.

Additionally, engineering analyses (EC 75588 and General Electric-Hitachi proprietary report 4221 .110-000-043 "operability Assessment of the River Bend Station Feedwater Sparger Assembly in the January 2018 As-Found Condition) and empirical data shows the feedwater sparger N4C has had negligible impact to the indicated level. The instrument continues to meet the performance requirements specified by General Electric Instrument Setpoint Methodology, NEDC-31336-A. Channel check performance is within the criteria specified by the General Electric Design Specification Data Sheet 22A3778AB and the subject instruments are operating satisfactorily, performing their specified function and remains within the allowable values specified by RBS Technical Specifications.

The basis and justification for EOI's position are provided below.

Approved Methodology The method used by RBS to establish Analytical Limits, Allowable Values and Nominal Trip Setpoints is described in the General Electric Instrument Setpoint Methodology, NEDC - 31336P-A, and was approved by the NRC in November 6,1995. The treatment of uncertainties and setpoint calculations in this methodology is consistent with RG1 .105 and ISA 67.04 1994.

1

ATTACHMENT 1 Basis for Denial of NCV 05000458/2018012-05 :

"Failure to Develop an Adequate Operational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the

. Feedwater System Sparger Nozzles" Example 2 NEDC -31336P-A provides guidance to determine Allowable Values and Nominal Trip Setpoints from the following :

From Section 1.2.1 Definitions

  • "Analytical Limit (AL) : The value of the sensed process variable established as part of the safety analysis prior to or at the point which a desired action is initiated to prevent the safety process variable from reaching the associated licensing safety limit."
  • "Allowable Value (A V) (Technical Specification Limit): The Limiting value of the sensed process variable at which the trip setpoint may be found during instrument surveillance. Usually prescribed as a license condition ."
  • "Nominal Trip Setpoint (NTSP) : The limiting value of the sensed process variable at which a trip action may be set to operate at time of calibration."

From Section 1.2.2 Setpoint Relationships :

"The Steps involved in establishing safety system setpoints are summarized in Figure 1-1."

"The difference between the Analytical Limit (AL) and the Allowable Value (AV) of the setpoint allows for channel instrument accuracy, calibration accuracy, process measurement accuracy, and primary element accuracy."

"The margin between the Allowable Value (AV) and the Nominal Trip Setpoint (NTSP) allows for the instrument drift that might occur during the established surveillance period."

LSL:

AV : Allowable Licensing Steady State NTSP: Nominal Value (Tech AL: Ana lytical Safety Operating Value Trip Setpoint Specs) Limit Limit SetpointiLimits:

I I I I Margins For: Spurious Trip LER Avoidance Measurement Accuracy Safety Analysis Avoidance Factors Determining A. Perturbations A. Channel instrument A. Channel instrument A. Modelling Margins: resu lting from drift accuracy accuracy limiting normal operating transient B. Channel B. Channel calibration B. Response time accuracies accuracy C. Modelling C. Process measurement C. Transient overshoot accuracy accuracy D. Primary element accuracy Figure 1*1 Instrument Setpoint Relationships 2

ATTACHMENT 1 Basis for Denial of NCV 05000458/2018012-05 :

"Failure to Develop an Adequate Ope rational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the Feedwater System Sparger Nozzles" Example 2 Therefore , in the RBS licensing and design basis methodology, the Analytical Limit is established to protect the Safety Limit. The Allowable Value is established to protect the Analytical Limit considering channel instrument accuracy, channel calibration accuracy, process measurement accuracy, and primary element accuracy. The Nominal Trip Setpoint is established to protect the Allowable Value considering channel instrument drift. The purpose of this Nominal Trip Setpoint is consistent with the inspection report's quote from the RBS Technical Specifications Bases:

"The nominal setpoints are selected to ensure that the actual setpoints do not exceed the Allowable Value between successive channel calibrations ."

The potential bias induced by the degraded feedwater sprager would impact the "process measurement accuracy," as a result, it would be considered in the determination of the Allowable Value's relationship to the safety analysis in the RBS licensing and design basis methodology. Therefore, RBS's assessment of the subject potential new bias considering the margin between the Allowable value and the Analytical Limit was appropriate.

Technical Specification Impact Based on the guidance in NEDC-31336P-A, EOI respectfully disagrees with the following statement in NCV 05000458/2018012-05:

"For Example 2, the performance deficiency was more than minor, and therefore a finding , because if left uncorrected it would have the potential to lead to a more significant safety concern . Specifically, the use of less conservative calculated values than the Allowable Values stated in the facility TS as a basis for establishing a threshold for operability of TS equipment could result in the inappropriate evaluation of actual degraded conditions that impact the ability of components to perform their required safety functions."

The preservation of the Analytical Limit protects the safety limit and the associated ability to perform the required safety functions, not the Allowable Value. The General Electric definition of Analytical Limit accepted by the staff from NEDC-31336P-A, as described on page 4 of the associated NRC Safety Evaluation Report, is:

  • "Analytical Limit (AL) : The value of the sensed process variable established as part of the safety analysis prior to or at the point which a desired action is initiated to prevent the safety process variable from reaching the associated licensing safety limit."

RBS performed an evaluation , accounting for this new potential bias, and determined that all "known uncertainties between the Analytical Limit and the Nominal Trip Setpoint" were accounted for in the margins available within the current calculation to protect the Analytical Limit and, as a result, the ability to perform the safety function was always protected.

3

ATTACHMENT 1 Basis for Denial of NCV 05000458/2018012-05:

"Failure to Develop an Adequate Operational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the Feedwater System Sparger Nozzles" Example 2 Conclusions Entergy respectfully proposes the removal of Example 2 from the River Bend Station - NRC Baseline Inspection Report violation 05000458/2018012-05 , "Failure to Develop an Adequate Operational Decision-Making Issue for Compensatory Measures Related to a Degraded Condition of the Feedwater System Sparger Nozzles". The violation states that the damage on feedwater sparger N4C could create unexpected feedwater flow paths in the reactor vessel during plant operation and potentially adversely affect the "B" variable leg reactor water level instruments and the (Level 3) and high level (Level 8) actuation beyond the allowable values specified by RBS Technical Specifications.

Engineering analyses (EC 75588 and General Electric-Hitachi proprietary report 4221.110-000-043 "operability Assessment of the River Bend Station Feedwater Sparger Assembly in the January 2018 As-Found Condition) and empirical data shows the feedwater sparger N4C has had negligible impact to the indicated level. The instrument continues to meet the performance requirements specified by General Electric Instrument Setpoint Methodology (NEDC-31366) as approved by the NRC Safety Evaluation Report dated November 6, 1995. Channel check performance is within the criteria specified by the GE Design Specification Data Sheet 22A3778AB and the subject instruments are operating satisfactorily, performing their specified function and remains within the allowable values specified by RBS Technical Specifications.

4

ATTACHMENT 2 Basis for Denial of NCV 05000458/2018012-07:

"Failure to Perform 10 CFR 50.59 Evaluation for Main Feedwater System Sparger Nozzle Damage"

ATTACHMENT 2 Basis for Denial of NCV 05000458/2018012-07:

"Failure to Perform 10 CFR 50.59 Evaluation for Main Feedwater System Sparger Nozzle Damage" Summary of Violation In reference to the NRC Letter dated July 18, 2018, "River Bend Station - NRC Baseline Inspection Report 05000458/201812 (ML 18194A 13), the U.S. Nuclear Regulatory Commission (NRC) identified a traditional enforcement Severity Level IV Non-Cited Violation (NCV 05000458/2018012-07) during the performance of a Baseline Inspection at River Bend Station (RBS) . This Inspection concluded July 16, 2018. The violation summary states:

"The inspectors identified a Severity Level IV NCV of 10 CFR 50.59, "Changes, Tests, and Experiments," for the licensee's failure to provide a written safety evaluation for the determination that operation with compensatory measures for damaged feedwater sparger nozzles did not require a license amendment pursuant to 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit."

Specifically, the licensee failed to recognize that compensatory measures prohibiting operation in single loop conditions required technical specification changes, and as such required prior NRC approval."

Based on a detailed review of applicable NRC regulations and NRC guidance documents, relative to the documents reviewed by the NRC inspectors during the Baseline Inspection ,

Entergy Operations, Inc. (EOI) respectfully disagrees with the NRC's assessment and conclusions for NCV 05000458/2018012-07 that are stated in Inspection Report (Reference 1).

The basis and justification for EOl 's position are provided below.

50.59 Screening The NRC provided the following statement concerning the failure to perform a 10 CFR 50.59 evaluation:

"Because the licensee did not perform a 50.59 screening for the compensatory measures associated with the restricted operating conditions , the licensee failed to recognize that the TSs were now non-conservative and that NRC approval was required ."

EOI respectfully disagrees with this statement. On January 29, 2018, RBS performed a 10 CFR 50.59 screening of the compensatory measures associated with Condition Report (CR)-RBS-2018-00613, prior to implementation of the compensatory measures. This 10 CFR 50.59 screening, and the associated Operability Evaluation are documented in CR-RBS-2018-00613, Corrective Action (CA) 001. 'The 10 CFR 50.59 screening specifically identified the following as one of four compensatory measures comprising the activity that was being screened: "RBS will not operate in Single Loop Operation ."

Regulatory Basis - Compensatory Measures Compensatory measures related to the FW system sparger nozzle damage were implemented by the RBS Operational DeCision-Making Issue (ODMI) that is documented in CR-RBS-2018-00613, CA 006. The compensatory measures in the ODMI impose short-term administrative controls that are more restrictive than the current Technical Specifications (TS) for Single Loop Operation (SLO). Implementation of these administrative controls is within the operating authority provided by the TS. The ODMI will remain in place until repairs are made to the FW I

ATTACHMENT 2 Basis for Denial of NCV 05000458/2018012-07:

"Failure to Perform 10 CFR 50.59 Evaluation for Main Feedwater System Sparger Nozzle Damage" system sparger during the next refueling outage (Le. , Spring 2019) , although they may be modified as additional information becomes available. The repairs to the FW system sparger are considered the "final corrective action" and will result in the full restoration of all functions to the original Licensing Basis. Therefore, no TS changes will be required as part of the final corrective action.

Imposing compensatory measures, on a short-term basis, to address a degraded or non-conforming condition is an NRC-acknowledged method of maintaining operability or to otherwise assure safety for an interim period. NRC Inspection Manual Chapter (IMC) 0326, "Operability Determinations and Functionality Assessments for Conditions Adverse to Quality or Safety" (Reference 2) , Section 07.03, "Compensatory Measures" states:

"When evaluating the effect of a degraded or nonconforming condition on an SSC's capability to perform any of its specified safety functions , a licensee may decide to implement compensatory measures as an interim action until final corrective action to resolve the condition is completed ."

IMC 0326, Section 07.04, "Final Corrective Action ," provides the following guidance concerning implementation of more restrictive requirements while working to implement final corrective actions:

"The proposed final resolution may require staff review and approval (via amendment) without affecting the continued operation of the plant because interim operation is governed by the processes for determining operability and taking corrective action (10 CFR Part 50, Appendix B)."

"In both situations, the potential need to obtain NRC approval for a change does not affect the licensee's authority to operate the plant. The licensee may make mode changes, restart from outages, etc., with degraded or nonconforming conditions provided that operations in these conditions do not violate the TS or the license. The basis for this authority to continue to operate is that the TS contains the specific characteristics and conditions of operation necessary to avoid an abnormal situation or event that might give rise to an immediate threat to public health and safety. "

The current situation at RBS is consistent with these NRC statements in that RBS has imposed interim actions which do not violate the TS or operating license. The RBS administrative restriction on SLO operation is not intended to avoid an abnormal situation or event that might give rise to an immediate threat to public health and safety, but rather to protect the vessel from potential long term affects.

The potential effects of FW system sparger leakage on the reactor pressure vessel have been extensively evaluated by both the industry and the NRC. General Electric (GE) document NEDE-21821 -A, "Boiling Water Reactor Feedwater Nozzle/Sparger Final Report, February 1980" provides an extensive evaluation and recommendations for reducing the leakage and reducing the impact of leakage. This NEDE formed the technical basis for the 50.54(f) request to licensees described in NUREG-0619, "BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking: Resolution of Generic Technical Activity A-10," and Generic Letter 81 -

11 , "BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking (NUREG-0619)." These evaluations described the low impact of these conditions (e.g., a leaking FW system sparger) on available margin .

2

ATTACHMENT 2 Basis for Denial of NCV 05000458/2018012-07:

"Failure to Perform 10 CFR 50.59 Evaluation for Main Feedwater System Sparger Nozzle Damage" Finally, EOI desires to clarify the applicability of the following statement from the Inspection Report (Reference 1) to the current issue at RBS:

"The NRC staff expects that, following the imposition of administrative controls, an amendment to the TS, with appropriate justification and schedule, will be submitted in a timely fashion. Once any amendment correcting the TS is approved, the licensee must update the final safety analysis report, as necessary, to comply with 10 CFR 50.71 (e) ."

In the Administrative Letter, AL 98-10, "Dispositioning of Technical Specifications that are Insufficient to Assure Plant Safety" (Reference 4), this statement refers to discovery and correction of an improper or inadequate TS value or required action . The current RBS FW system condition and the resultant compensatory measures do not represent an improper or inadequate TS value or required action. If the final corrective action for the degraded condition was to accept the condition into the licensing basis this statement would apply.

In addition, if RBS decided the final corrective action for this condition was to accept the condition into the licensing basis, then the following statement from IMC 0326 , Section 7.04 would apply:

"If the 10 CFR 50.59 screening and/or evaluation concludes that a change to the TS is involved or the change meets any of the evaluation criteria specified in the rule for prior NRC approval, a license amendment must be requested and the corrective action process is not complete until the approval is received or some other resolution occurs."

Since RBS plans to repair the degraded condition during the next refueling outage, as opposed to implementation of a design and licensing basis change (i.e. , to accept the condition as-found), the corrective action process for this issue will not be complete until repairing the degraded condition resolves the issue.

Conclusions RBS performed a 10 CFR 50.59 screening of the compensatory measures associated with CR-RBS-2018-00613 on January 29, 2018, prior to implementation of the compensatory measures.

This 10 CFR 50.59 screening is documented in CR-RBS-2018-00613, CA 01 . As such, EOI respectfully disagrees with the NRC position that a 10 CFR 50.59 screening was not performed.

Given the NRC guidance in References 2 and 3 concerning implementation of administrative controls as a short-term corrective action to address a degraded or non-conforming condition (i.e., pending final corrective action to fully restore a degraded component), EOI respectfully disagrees with the NRC position that a change to the TS for Single Loop Operation is required.

References

1. NRC Letter dated July 18, 2018, "River Bend Station - NRC Baseline Inspection Report 05000458/201812 (ML 18194A 13)
2. NRC IMC 0326, "Operability Determinations and Functionality Assessments for Conditions Adverse to Quality or Safety" (ML13274A578) 3

ATTACHMENT 2 Basis for Denial of NCV 05000458/2018012-07:

"Failure to Perform 10 CFR 50.59 Evaluation for Main Feedwater System Sparger Nozzle Damage"

3. NRC Administrative Letter (AL) 98-10, "Dispositioning of Technical Specifications that are Insufficient to Assure Plant Safety"
4. NEI 96-07, Revision 1, "Guidelines for 10 CFR 50.59 Implementation" (ML003771157) 4
Retrieved from "https://kanterella.com/w/index.php?title=RBG-47896,_Response_to_NRC_Baseline_Inspection_Report_05000458/2018012&oldid=1923574"