RBG-47807, Response to License Renewal Application NRC Requests for Additional Information Set 3

Response to License Renewal Application NRC Requests for Additional Information Set 3

ML18010A848
Person / Time
Site:	River Bend
Issue date:	01/10/2018
From:	Maguire W Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RBG-47807
Download: ML18010A848 (12)

Text

~. Entergx RBG-47807 January 10, 2018 Attn: Document Control Desk U.S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2738 Entergy Operations. Inc.

River Bend Station 5.)85 U.. Highway 61 N St Frdl'clsvlite. LA 70775 fel )25*381*4374 William F. Maguire Site Vice President River BE'nd Statton

SUBJECT:

Response to License Renewal Application NRC Requests for Additional Information Set 3 River Bend Station, Unit 1 Docket No. 50-458 License No. NPF-47

References:

1) Entergy Letter: License Renewal Application (RBG-47735 dated May 25, 2017)

2) NRC email: River Bend Station, Unit 1, Request for Additional Information, Set 3 - RBS License Renewal Application - dated November 29, 2017 (ADAMS Accession No. ML17335A098)

3) Entergy Letter: Request for Due Date Extension for License Renewal Application NRC Request for Additional Information - Set 3 (RBG-47809 dated December 12, 2017)

Dear Sir or Madam:

In Reference 1, Entergy Operations, Inc (Entergy) submitted an application for renewal of the Operating License for River Bend Station (RBS) for an additional 20 years beyond the current expiration date. In an email dated November 29, 2017, (Reference 2) the NRC staff provided Requests for Additional Information (RAls), needed to complete the license renewal application review. On December 12, 2017, (Reference 3) Entergy requested that the due date for response to these requests be extended from December 29, 2017, to January 10, 2018. The extension was requested due to the limited personnel resources available during the latter part of December 2017. Enclosure 1 provides the responses to the Set 3 RAls.

If you require additional information, please contact Mr. Tim Schenk at (225)-381-4177 or tschenk@entergy.com.

RBG-47807 Page 2 of 3 In accordance with 10 CFR 50.91 (b)(1), Entergy is notifying the State of Louisiana and the State of Texas by transmitting a copy of this letter.

I declare under penalty of perjury that the foregoing is true and correct. Executed on January 10, 2018.

Sincerely, WFM/RMC/alc

RBG-47807 Page 3 of 3 : Set 3 RAI Responses - River Bend Station cc:

(with Enclosure)

U. S. Nuclear Regulatory Commission Attn: Emmanuel Sayoc 11555 Rockville Pike Rockville, MD 20852 cc:

(w/o Enclosure)

U. S. Nuclear Regulatory Commission Attn: Lisa Regner 11555 Rockville Pike Rockville, MD 20852 U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Blvd.

Arlington, TX 76011-4511 NRC Resident Inspector PO Box 1050 St. Francisville, LA 70775 Central Records Clerk Public Utility Commission of Texas 1701 N. Congress Ave.

Austin, TX 78711-3326 Department of Environmental Quality Office of Environmental Compliance Radiological Emergency Planning and Response Section Ji Young Wiley P.O. Box 4312 Baton Rouge, LA 70821-4312 RBF1-17-0154

RBG-47B07 Response to Requests for Additional Information Set 3

RBG-47807 Page 1 of 8 Question REQUESTS FOR ADDITIONAL INFORMATION LICENSE RENEWAL APPLICATION RIVER BEND STATION, UNIT 1 - SET 3 DOCKET NO.: 50-458 CAC NO.: MF9757 Office of Nuclear Reactor Regulation Division of Materials and License Renewal RAI 3.2.2.3.2-1 (Generic Filtration)

Background

LRA Table 2.0-1, "Component Intended Functions: Abbreviations and Definitions," states that the filtration function is, "[p]rovide removal of unwanted materiaL" LRA Table 2.0-1 states that the mechanical pressure boundary function is, "[p]rovide pressure boundary integrity such that adequate flow and pressure can be delivered... "

LR-ISG-2012-02, "Aging Management of Internal Surfaces, Fire Water Systems, Atmospheric Storage Tanks, and Corrosion Under Insulation," added a new term, flow blockage," defined as:

Flow blockage is the reduction of flow or pressure, or both, in a component due to fouling, which can occur from an accumulation of debris such as particulate fouling (e.g., eroded coatings, corrosion products), biofouling, or macro fouling. Flow blockage can result in a reduction of heat transfer or the inability of a system to meet its intended safety function, or both. This definition is consistent with the definition of the term "pressure boundary" as found in SRP-LR Table 2.1-4(b), "Typical 'Passive' Component-Intended Functions."

In addition, the term fouling was revised to state in part, "[f]ouling can result in a reduction of heat transfer, flow or pressure, or a loss of materiaL" SRP-LR, Section A.1.2.1, Applicable Aging Effects states, in part, that the effects of aging on the intended functions of components should be considered. In the case of components with an intended function of filtration, flow blockage due to fouling would appear to be an applicable aging effect to be considered. In addition, Section A.1.2.1 also states:

An aging effect should be identified as applicable for license renewal even if there is a prevention or mitigation program associated with that aging effect. For example, water chemistry, a coating, or use of cathodic protection could prevent or mitigate corrosion, but corrosion should be identified as applicable for license renewal, and the AMR should consider the adequacy of the AMP referencing water chemistry, coating, or cathodic protection.

Issue Several LRA Table 2s cite components with a filtration intended function, see table below. None of the Table 2 entries cite flow blockage due to fouling as an aging effect requiring management (AERM). The staff recognizes that for some components, flow blockage due to fouling might be effectively managed by routine plant operations, for example, differential pressure is monitored on

RBG-47S07 Page 2 of S both sides of the component that has a filtration function. In other instances, flow blockage due to fouling might not be an applicable AERM, for example, a stainless steel strainer in a treated-water environment that has no internal coating or material/environment subjected to loss of material due to general corrosion upstream of the strainer. Based on the staff's review of the LRA, current licensing basis, and the associated components, the staff lacks sufficient information to conclude that the pressure boundary function of downstream components would be met if flow blockage due to fouling is not managed for the following components.

Table No.

System Component Type 3.2.2-2 High Pressure Core Spray Strainer 3.2.2-3 Residual Heat Removal Cyclone separator, Orifice 1, Strainer 3.2.2-4 Low Pressure Core Spray Strainer 3.2.2-5 Reactor Core Isolation Cooling Strainer2 3.2.2-6 Standby Gas Treatment Moisture separator 3.3.2-1 Control Rod Drive Filter 3.3.2-3 Service Water Strainer 3.3.2-4 Compressed Air Strainer 3.3.2-6 Main Steam Positive Leakage Control Strainer 3.3.2-10 Standby Diesel Generator Strainer 3.3.2-11 HPCS Diesel Generator Strainer 3.3.2-12 Control Building HVAC Demister 3.3.2-13 Miscellaneous HVAC Screen 3.3.2-14 Chilled Water Strainer, Air dryer 3.3.2-17 Fuel Oil Strainer 3.4.2-1 Condensate Makeup, Storage and Transfer Screen Notes:

1) For the residual heat removal system, as noted on P&IDs27-07A, and 27-07B, the restricting orifice plates for RHS-R020SA and R020SB were replaced with an "Inline Drag Resistor." This multistage flow restricting device was designed to eliminate cavitation, and consists of a set of 149 "punched disks," in addition to a multi-port baffle plate, which allow particles 0.125 inch diameter or less to pass. Although not intended to function as strainers, based on a review of the drawing for the inline drag resistor, it is not clear how large the openings are in order to determine if these components will act as strainers.

2) For the reactor core isolation cooling system, as noted on P&ID 27-06A, there is a pump inlet strainer, STRT1, shown for E51-PC003 "Sub System Fill Pump." Although Note 9 says the strainer element for STRT2 for E51-PC001, "Reactor Core Isolation Cooling Pump" was removed, there is no comparable note associated with STRT1 for the Sub System Fill Pump. It is not clear to the staff whether the E51-PC003 strainer was removed.

RBG-47807 Page 3 of 8 Request

1. State the basis for why the core spray inline drag resistor does not act as a strainer, or if it could, respond to Request No. 3.

2. State whether the E51 -PC003 strainer was removed. If it has not been removed, respond to Request No.3.

3. For each of the above components that cite filtration as an intended function, state the basis for why flow blockage due to fouling is not considered as an applicable AERM. Alternatively, revise the Table 2s, cite the AMP(s) that will be used to manage this AERM, and revise the AMP(s) to address this AERM.

Response

1. Note 1 indicates that the component in question is in the RHR system rather than the core spray system as specified in the request. The RHR Drag in-line resistors were installed to reduce vibration in RHR test return lines. The Drag resistors have holes in them large enough to pass particles up to 0.125 inches in diameter. These components are downstream of the RHR pump suction strainers in the suppression pool which have an opening size of 0.0937 inches. The suction strainers would trap any debris large enough to be trapped by the Drag resistors. Therefore, this component does not function as a strainer.

2. The STRT1 temporary strainer for the E51 -PC003 RCIC fill pump has been removed from the system.

3. As discussed in LR-ISG-2012-02, fire water piping and piping components are susceptible to flow blockage due to operating conditions of the system, such as periodically wetted piping that is normally dry. Flow blockage is applicable to piping components, such as nozzles, that are not designed to collect particulates, such as degraded coatings, corrosion products, and biological fouling products. Unlike piping and piping components, strainers and filters are designed to collect debris from a fluid and allow its removal to prevent damage and maintain function of downstream components. This debris collection, whether from aging effects or other causes, is anticipated to occur and provisions have been incorporated into the system design and operation, as necessary, to manage the collection of debris on the strainer or filter such that the active function of providing system flow can continue to be accomplished. As discussed in the Issue section of this RAI, strainers and filters are designed such that fouling is detected through various means, such as, monitoring differential pressure across the component or monitoring system flow during testing or normal operation. They can then be cleaned to maintain the active function of providing flow. Fouling of strainers or filters is not an aging effect, but is an effect of system operation that is managed, both during the original license term and during the period of extended operation, through operational features and monitoring activities that are discussed in the table below.

The table below provides information on the components identified in the request above with filtration as a component intended function. Included in the last column is the basis for why routine monitoring of the active function of flow delivery manages potential flow blockage of the strainers.

RBG-47807 Page 4 of 8 LRA Table No.

3.2.2-2 3.2.2-3 3.2.2-4 3.2.2-5 3.2.2-6 System Name High Pressure Core Spray Residual Heat Removal Low Pressure Core Spray Reactor Core Isolation Cooling Standby Gas Component Type I Description Strainer / HPCS pump suppression pool suction strainer CSH-STR1 Cyclone separator /

RHR pump seal water supply Strainer / RHR pump suppression pool suction strainers RHS-STR1A, 1 Band 1 C Strainer / LPCS pump suppression pool suction strainer CSL-STR1 Strainer / suppression pooIICS-STR1 Moisture separator /

Additional Basis for Monitoring Active Flow Delivery Function This ECCS suction strainer is designed for post LOCA debris loading that is significantly higher than would be experienced from the collection of debris related to aging effects. In addition, the strainer is inspected for debris and cleaned as necessary every refueling outage to ensure there is no buildup of debris that could affect the function of downstream components.

Cyclone separators are self-cleaning using cyclonic action to remove debris such that flow blockage does not occur.

This ECCS suction strainer is designed for post LOCA debris loading that is significantly higher than would be experienced from the collection of debris related to aging effects. The pumps are periodically tested with suction through the strainers that would identify significant debris buildup.

In addition, the strainer is inspected for debris and cleaned as necessary every refueling outage to ensure there is no buildup of debris that could affect the function of downstream components.

This ECCS suction strainer is designed for post LOCA debris loading that is significantly higher than would be experienced from the collection of debris related to aging effects. In addition, the strainer is inspected for debris and cleaned as necessary every refueling outage to ensure there is no buildup of debris that could affect the function of downstream components.

Suppression pool suction strainer is designed to support RCIC operation with 50% blockage which would not be expected to occur from debris related to aging effects. In addition, the strainer is inspected for debris and cleaned as necessary every refueling outage to ensure there is no buildup of debris that could affect the function of downstream components.

These devices are designed to remove

RBG-47807 Page 5 of 8 LRA Table No.

3.3.2-1 3.3.2-3 3.3.2-4 3.3.2-6 3.3.2-10 System Name Treatment Control Rod Drive Service Water Compressed Air Main Steam Positive Leakage Control Standby Diesel Generator Component Type I Description Inlet to charcoal filter Filter / CRD hydraulic control units (HCU)

Strainer / Penetration valve leakage control compressor A and B seal water makeup line, service water heat exchanger (HX) inlet (service water, system SWP), service water heat exchanger inlet (service water cooling, system SWC)

Strainer / Inlet strainers to instrument air solenoid valves Strainer / Penetration valve leakage control compressor seal water cooler outlet Strainer / Air start supply line, lube oil pump discharge, and lube oil sump tank heater circ pump discharge Additional Basis for Monitoring Active Flow Delivery Function moisture from the air not particulates.

Differential pressure indication is provided that is alarmed prior to flow blockage affecting intended function.

These small filters in the HCUs are inspected and replaced as necessary during rebuilds. The water in the CRD system is treated water from condensate storage with minimal particulates and the majority of components are stainless steel. In addition, normal operation of CRDs would allow detection if flow blockage of filters occurred.

Flow blockage in these service water strainers would be detected by differential pressure indication and alarm on the strainer (SWC HX) or via local pressure indication across the strainer (SWP HX). For the penetration valve compressors, it would be detected through normal system operation via compressor performance with reduced seal water makeup flow.

In addition, the makeup line strainers are periodically inspected and cleaned as necessary.

Flow blockage would be detected by abnormal operation of the downstream components supplied by the solenoid valves during normal operation and periodic testing.

Flow blockage of the strainers would be detected through normal operation of the compressors via temperature and performance monitoring. In addition, the cooler outlet strainers are periodically inspected and cleaned as necessary.

Air flowing through the air start supply line strainers is dried air such that there should be no debris or deposits to cause flow blockage.

The lube oil system is managed to minimize the potential for water accumulation and debris that could cause blockage. However, flow blockage of the lube oil pump discharge strainers would be detected by alarmed differential pressure

RBG-47807 Page 6 of 8 LRA Table No.

3.3.2-11 3.3.2-12 3.3.2-13 3.3.2-14 3.3.2-17 3.4.2-1 System Name HPCS Diesel Generator Control Building HVAC Miscellaneous HVAC Chilled Water Fuel Oil Condensate Makeup, Storage Component Type I Description Strainer / Air start, lube oil pump discharge, lube oil sump pump suction and lube oil sump main bearing press pump suction Demister / Charcoal filter housing inlet Screen / Upstream of HVR-AOV123 and 128 Strainer / HVAC chilled water chiller purge unit gas from condenser inlet, chilled water chiller purge unit liquid from condenser inlet and chilled water pump suction Dryer / HVAC chilled water chiller evaporator filter dryer Strainer / fuel oil day tank supply lines to diesels Screen / Condensate storage tank vent bird Additional Basis for Monitoring Active Flow Delivery Function switches, and lube oil heater circ pump strainer blockage would be detected during standby operation of the diesels via abnormal pressure due to a reduction in flow.

Air flowing through the air start supply line strainers is dried air such that there should be no debris or deposits to cause flow blockage.

This lube oil system is managed to minimize the potential for water accumulation and debris that could cause blockage. However, flow blockage of the lube oil pump discharge and suction strainers would be detected during normal testing and operation of the diesel via abnormal temperatures and pressures due to a reduction in flow..

These devices are designed to remove moisture from the air not particulates.

Flow blockage would be detected via alarmed differential pressure indication.

These screens are grating installed to protect valves from large debris during a loss of coolant accident. Flow blockage is not credible during normal operation due to the size of openings in the screen grating.

The air dryers are designed to remove moisture from Freon (not debris) such that flow blockage is not an aging effect. The strainers on the chiller purge units contain Freon liquid and gas that should contain no debris.

Flow blockage of the strainers, if it occurred, would be detected through chilled water system and chiller operation and testing.

The fuel oil system is managed to minimize the potential for water accumulation, particulates, sediment and debris that could cause blockage in these strainers. However, flow blockage would be detected by alarmed differential pressure indication.

Flow blockage due to fouling is not credible for this #10 mesh screen

RBG-47807 Page 7 of 8 LRA Table No.

Question System Name and Transfer Component Type I Additional Basis for Monitoring Description Active Flow Delivery Function screen exposed to air that is designed to prevent birds from entering the tank vent.

RAI 3.4.1.11 -1 (Potential Aging Effects of Control Rod Drive (CRD) Hydraulic Control Unit (HCU)

Accumulators)

Background

LRA Table 3.3.2-1 addresses aging management review results for the control rod drive hydraulic system. The LRA table indicates that stainless steel accumulators, exposed to treated water (greater than 140 °C), are subject to cracking due to stress corrosion cracking (SCC) and that the aging effect of SCC is managed by using the Water Chemistry Control - BWR Program and the One-Time Inspection Program.

During the audit, the staff noted that CR-RBS-2015-00855 (dated February 11, 2015) addresses an adverse trend of equipment reliability for the hydraulic control unit (HCU) accumulators in the control rod drive hydraulic system. The CR indicates an increasing trend of high temperature alarms for these HCU accumulators and a plan for accumulator replacements. In addition, The CR indicates that these accumulators are made with carbon steel or stainless steel and that preventive maintenance activities will be emphasized to prevent accumulator faults.

Issue The staff needs additional information to clarify whether aging effects are associated with the reliability concern of the accumulators discussed above.

Request

1. Provide additional information on the following: (1) whether aging effects are associated with the reliability concern of HCU accumulators (e.g., the reliability issue resulted from aging effects or high temperature conditions facilitated aging effects); and (2) if aging effects are associated with the reliability concern, what aging effects are involved and what aging management programs and activities are used to manage the aging effects.

2. Revise aging management review results for these accumulators (e.g., LRA Table 3.3.2-1), as needed.

Response

1. Entergy identified an adverse trend for alarms received on the HCU accumulators. The alarms do not indicate that the control rod drive HCU accumulators would be unable to accomplish their intended function, but they detect leakage internal to the accumulator.

USAR Section 4.6.1.1.2.4.3.9 describes the accumulator as a free floating piston in a hydraulic cylinder with associated nitrogen pressure alarm and water leakage alarm. These alarm conditions result from reduction of nitrogen pressure or water leakage past the moveable piston that separates the nitrogen and the water within the accumulator. The piston

RBG-47807 Page 8 of 8 with its associated sealing features performs its function with moving parts and is, therefore, not subject to aging management review in accordance with 10 CFR 54.21 (a)(1).

Loss of material from the internal surfaces of the carbon steel cylinders has been a contributor to the trend of alarms associated with the accumulators. To reduce the number of alarms associated with the accumulators, a plan was approved in 2016 to replace the remaining carbon steel accumulators with stainless steel accumulators over the next four refueling outages. As indicated in LRA Table 3.3.2-1, the Water Chemistry Control-BWR Program manages loss of material and cracking of the HCU accumulators to maintain the passive pressure boundary function.

2. The aging effects on the passive accumulator are managed as identified in LRA Table 3.3.2-1.

Since the alarm conditions do not indicate a loss of intended function for the accumulators, no change to the LRA is warranted.

Question 3.3.2.1-1 (Aging Management for Control Rod Drive (CRD) Hydraulic Control Unit (HCU)

Directional Control Valve (DCV) Cap Screws)

Background

LRA Table 3.3.2-1 addresses aging management review results for the control rod drive hydraulic system. During the audit, the staff noted that CR-RBS-2016-02942 addresses signs of corrosion in ASTM A574 cap screws of control rod drive (CRD) hydraulic control unit (HCU) directional control valves (DCVs). This CR indicates that the cap screws are used to maintain the pressure boundary integrity of DCVs. The CR further indicates that, as addressed in GE SIL 678, these alloy steel cap screws are susceptible to stress corrosion cracking.

Issue LRA does not clearly address aging management programs or activities that are used to manage loss of material due to corrosion and cracking due to stress corrosion cracking for these HCU DCV cap screws.

Request Describe aging management programs and activities that the applicant uses to manage loss of material and cracking for these cap screws. In addition, revise the LRA to describe the aging management programs and activities, as needed.

Response

In accordance with GE SIL 678, RBS replaced the directional control valve cap screws on all 145 hydraulic control units with material that is not susceptible to stress corrosion cracking. Therefore, the LRA does not require revision to identify cracking of the directional control valve cap screws.

The component type utilized for cap screws is "bolting." The Bolting Integrity Program manages loss of material and loss of preload for bolting as identified in LRA Table 3.3.2-1.