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ER-W3-2004-0602-000, Steam Generator Feedwater Pump Trip Logic Modification Due to Extended Power Up-rate
	ML061280090
Person / Time
Site:	Waterford
Issue date:	02/28/2005
From:	Nobles R; Entergy Nuclear South
To:	; Office of Nuclear Reactor Regulation
References
	ER-W3-2004-0602-000
	Download: ML061280090 (10)
	v • d • e

Page 1 of 10 I.

OVERVIEW F SIGNATURES Facility: Waterford 3 Document Reviewed : ER Pressure Trip Description of Proposed Change LI-101-U1, Rev. 6 3-2004-0602-000. Feed System Designator(s)lDescription : CFWS-Condensate and Feedwater Systems ChangeiRev.: Rev. 0 Results of calculation ECM03-005 (performed for EPU) indicate that Waterford 3 cannot be operated at full load under EAU conditions with fewer than two heater drain pumps in service. Calculation results indicate that if two or three heater drain pumps are removed from service after implementation of EPU, feedwater pump NPSH is expected to decrease to the current low suction pressure trip setpoint, The existing feedwater pump trip logic design is such that the low suction pressure trip setpoint and associated pump trip time delay setpoint are identical for both feedwater pumps, therefore a low suction pressure condition is currently designed to automatically trip both feedwater pumps at basically the same time. More specifically, if a low suction pressure condition activates the pressure switches and suction pressure does not recover to the switch reset value (which is approximately 50-psi above the trip setpoint) before the 15-second time delay expires, then feedwater pump trip signals are activated for both feedwater pumps. This issue is addressed in EPU Supplement Letter W3F1-2005-0004, Attachment 3.

ER-W3-2004-0602-000 provides a remedy try modifying the feedwater pump trip logic. The setpoints for the low suction pressure switches are increased to cause one pump to trip earlier in a decreasing NPSH scenario, ensuring more water inventory in the steam generators at the time of pump trip. The reset value of the low suction pressure switches is decreased, which means that less time will be needed to recover from the low pressure condition and reset the pressure switches to a non-trip state. Additionally, the trip time delay for Feedwater Pump A is reduced, and the trip time delay for Feedwater Pump B is increased. The use of different time delays will allow one feedwater pump to trip after a short period of sustained low suction pressure, which will cause a turbine runback signal that reduces steam flowlfeedwater flow demands and thereby allows feedwater pump suction pressure to recover to a pressure greater than the reset value of the low pressure switches in time to prevent tripping of the second feedwater pump. These changes are based on DAR-OA-05-4.

Additionally, the low suction pressure alarm setpoint is increased to provide the Operator with a more advanced warning signal that feedwater pump suction pressure is decreasing.

FSAR Section 10.4.7.3 states that "The condensate and feedwater systems are capable of operation at full load with one out of three condensate primps out of service or all three heater drain pumps out of service". This FSAR section is revised to state that the condensate and feedwater systems are capable of operation at full load with one out of three heater drain pumps out of service and at partial load with two or three heater drain pumps out of service.

Check the applicable review(s): (Only the sections indicated must be included in the Review.)

(Section I

,N! SCREENING Sections I and 11 required

[1150-59 EVALUATION EXEMPTION Sections 1, 11, and III required z 50.59 EVALUATION 00 Sections 1, 11, and IV required

Page 2 of 10 Preparer:

R.S.Nobles ENERCON/Projectsl

.....-. a Name (print) I Sig attire f

, Company) Department/ Date Reviewer :

RKSchwartzbeck zz" Name (print) / Sign tire /

OSRC :

LI-101-01, Rev. 6 50.69 REVIEW FORM Z 2`d 2no ~'-"

lRequired only for Programmatic Exclusion Screenings (see Section 5.8) and 50.59 Evaluations.)

ENE iCONIDesign/

a fz.s-V-pany / Department I Date

11.

SCREENINGS A.

Licensinci Basis Document Review 1.

Does the proposed activity impact the facility or a procedure as described in any of the following Licensing Basis Documents?

' If "YES," see Section 5.2[5j. No LSD change is required.

z If "YES," notify the responsible department and ensure a 50.54 Evaluation is performed. Attach the 50,54 geview.

Changes to the Emergency Plan, Fire Protection Program, and Offsite Dose Calculation Manual must be approved by the OSRC in accordance with NMM OM-119.

If "YES," evaluate the change in accordance with the requirements of the facility's Operating License Condition or under 50.59, as appropriate.

LI-101-01, Rev. 6 LBDs controlled under other regulations YES NO CHANGE # (if applicable) and/or SECTIONS IMPACTED Quality Assurance Program Manual 2 l~

Emergency Plan2, s

© L

Fire Protection Program 3,4 (includes the Fire Hazards Analysis) 0 OR Offsite Dose Calculations Manual 3,

3,4 If "YES", evaluate any changes in accordance with the appropriate regulation AND initiate an LB D change in accordance with NMM ENS-LI-113. No further 50.59 review is required.

LBDs controlled under 50.59 YES NO CHANGE # (if applicable) and/or SECTIONS IMPACTED FSAR

TS Bases El Z

Technical Requirements Manual E3 0

Core Operating Limits Report a

NRC Safety Evaluation Report and

© I

supplements for the initial FSAR' NRC Safety Evaluations for El 11011 amendments to the Operating License' If "YES", perform an Exemption Review per Section III OR perform a 50.59 Evaluation per Section IV OR obtain NRC approval prior to implementing the change. If obtaining NRC approval, document the LBD change in Section II.A.5 ; no further 50.59 review is required. However, the change cannot be implemented until approved by the NRC. AND initiate an LBD change in accordance with NMM ENS-L1-113.

Operating License YES NO CHANGE # and/or SECTIONS IMPACTED Operating License

NRC Orders If "YES", obtain NRC approval prior to implementing the change by initiating an LBD in accordance with NMM ENS-LI-113.

change (See Section 5.2[13] for exceptions.)

2.

Does the proposed activity involve a test or experiment not described in the FSAR?

CJ Yes No

3.

Basis If "yes," perform a 50.59 Evaluation per Section 1V OR obtain NRC approval prior to implementing the change AND initiate an LBD change in accordance with NMM LI-113.

If obtaining NRC approval, document the change in Section II.A.5 ; no further 50.59 review is required. However, the change cannot be implemented until approved by the NRC.

Explain why the proposed activity does or does not impact the Operating License/Technical Specifications and/or the FSAR and why the proposed activity does or does not involve a new test or experiment not previously described in the FSAR_ Discuss other LBDs if impacted. Adequate basis must be provided within the Screening such that a third-party reviewer can reach the same conclusions. Simply stating that the change does not affect TS or the FSAR is not an acceptable basis.

Ogerat.n.q.License :

The operating license does not have any restrictions on activities within the scope of this change. None of the license conditions contained in the operating license are impacted by the activity within the scope of this ER.

Therefore, the proposed activity does not impact the Waterford Unit 3 operating license Technical

. Specifications:

FSAR :

LI-101-01, Rev. 6 Main Feed Pump trip logic and alarms are not addressed in the Technical Specifications. Therefore, the instrumentation setpoint and calibration changes within the scope of this ER do not require revision to the Technical Specifications.

The activities within the scope of this ER will not adversely affect the mode of operation of any important to safety equipment or Technical Specification associated equipment.

In addition, the activities will not create a system configuration or operating condition such that a Technical Specifications LCO or surveillance requirement is no longer adequate.

Likewise, the activities will not result in a condition that would bypass or invalidate automatic actuation features required to be operable by the Technical Specifications or exceed any limits specified in the Operating License and Technical Specifications.

The Condensate and Feedwater System (CFWS) is described in FSAR Section 10,4.7. Section 10_4.7.3 states that "The Condensate and Feedwater Systems are capable of operation at full load with one out of three condensate pumps out of service or all three heater drain pumps out of service". This FSAR section is revised to state that the condensate and feedwater systems are capable of operation at full load with one out of three heater drain pumps out of service and at partial load with two or three heater drain pumps out of service. This change is evaluated further in Section 1V of this 50.59 Review.

Section 10.4.7.5 lists the feedwater pump automatic trip signals, including low suction pressure trip. However, the details for each trip (instrument setpoints, time delays, etc.) are not included in the FSAR information. The changes to low suction pressure setpoints, reset values, time delay relay setpoints, and suction pressure alarm are below the level of detail for information that is required to be included in the FSAR. Therefore; the proposed changes do not impact the facility as described in this section of the FSAR.

The Turbine Control System JCS) is described in FSAR Section 7.7.1.4.2. One of the TCS functions, as described in this section, is to provide a turbine runback signal upon occurrence of loss of one feedwater pump or loss of load. The proposed changes to the feedwater pump low suction pressure trip logic will not affect the TCS functions as described_ Therefore, the FSAR-described functions for the TCS are not impacted by the proposed changes.

The Reactor Power Cutback System is described in FSAR Section 7.7,1.9. Section 7.71.9.1 specifies: The Reactor Power Cutback System (RPCS) is a control system designed to accommodate certain types of imbalances by providing a "step" reduction in reactor power. The step reduction in reactor power is accomplished by the simultaneous dropping of one or more preselected groups of regulating CEAs into the core. The CEA groups are dropped in their normal sequence of insertion. The RPCS also provides control signals to rebalance turbine and reactor power following the initial reduction in reactor power. The system is

Page 5 of 1 0 designed to accommodate the loss of one feedwater pump. Therefore, the FSAR-described functions for the RPCS are not impacted by the proposed changes.

Test or experiment not described in the FSAR ;

50.59 REVIEW FORM This activity does not involve a test or experiment. The activities are restricted to re-calibration of existing instruments using revised setpoints and calibration values.

The post-modification tests (calibration and instrument functional testing) do not adversely affect the operation of the plant and will be performed in accordance with approved plant procedures.

4.

References Discuss the methodology for performing LBD searches. State the location of relevant licensing document information and explain the scope of the review such as electronic search criteria used (e.g., key words) or the general extent of manual searches per Section 5.4.1[51(d) of LI-101. NOTE : Ensure that manual searches are performed using controlled copies of the documents. If you have any questions, contact your site Licensing department.

LBDs/Documents reviewed via an Autonomy Keywords :

keyword search :

Heater drain pumps, low pump suction pressure, FSAR Sections 4,2, 7.7.1.9, 7.7.1.4.2, 10.4.7.3, turbine runback, 225 psi, loss of normal feedwater 10.4.7.5, 15.2.2.5,15.2.3.2 : Tables 10.4-4, 15.2-6,15.2-7 ; SER Amendment No. 74, Section 2.5 LBDs/Documents reviewed manually :

FSAR Sections 4.2, 7.7.1.9, 7.7.1.4.2, 10.4.7.3, 10.4.7.5, 15.2.2.5, 15.2.3.2 : Tables 10.4-4, 15.2-6, 15.2-7; SER Amendment No. 74, Section 2.5

5.

Is the validity of this Review dependent on any other change?

LI-101-¬31, Rev. 6 Yes No If "YES", list the required changes/submittals. The changes covered by this 80.59 Review cannot be implemented without approval of the other identified changes (e.g., license amendment request).

Establish an appropriate notification mechanism to ensure this action is completed.

Validity of this review is dependent on concurrent implementation of ER-W3-2001-1149-000, Waterford 3 Extended Power Llprate. An ERD action item has been created to track this requirement.

Page 6 of 10 B.

ENVIRONMENTAL. SCREENING If any of the following questions is answered "yes," an Environmental Review must be performed in accordance with NNIM Procedure ENS-EV-115, "Environmental Evaluations," and attached to this 50.59 Review. Consider both routine and non-routine (emergency) discharges when answering these questions.

Will the proposed Change being evaluated:

Yes 1.

3.

4.

5.

6.

7.

8.

a 041 Ft OR 11,

[~

Involve the installation of stationary fuel burning equipment or use of portable fuel burning equipment (i.e., diesel fuel oil, butane, gasoline, propane, and kerosene)?'

12.

50.59 REVIEW FORM Involve a land disturbance of previously disturbed land areas in excess of one acre (i,e.,

grading activities, construction of buildings, excavations, reforestation, creation or removal of ponds)?

Involve a land disturbance of undisturbed land areas (i.e., grading activities, construction, excavations, reforestation, creating, or removing ponds)?

Involve dredging activities in a lake, river, pond, or stream?

Increase the amount of thermal heat being discharged to the river or lake?

Discharge any chemicals new or different from that previously discharged?

Modify the design or operation of the cooling tower that will change water or air flow characteristics?

Modify the design or operation of the plant that will change the path of an existing water discharge or that will result in a new water discharge?

Modify existing stationary fuel burning equipment (i.e., diesel fuel oil, butane, gasoline, propane, and kerosene)?'

Involve the installation or modification of a stationary or mobile tank?

Involve the use or storage of oils or chemicals that could be directly released into the environment?

Involve burial or placement of any solid wastes in the site area that may affect runoff, surface water, or groundwater?

' See NMM Procedure ENS-EV-117, "Air Emissions Management Program," for guidance in answering this question.

L.1-101-01, Rev. 6

Page 7 of 10 C.

SECURITY PLAN SCREENING If any of the following questions is answered "yes," a Security Plan Review must be performed by the Security Department to determine actual impact to the Plan and the need for a change to the Plan.

Could the proposed activity being evaluated :

L.I-101-01, Rev. 6 50.59 REVIEW FORM Documentation for accepting any "yes" statement for these reviews will be attached to this 50.59 Review or referenced below.

Yes No 1.

[]

0.9 Add, delete, modify, or otherwise affect Security department responsibilities (e.g.,

including fire brigade, fire watch, and confined space rescue operations)?

2.

OR Result in a breach to any security barrier(s) (e.g., HVAC ductwork, fences, doors, walls, ceilings, floors, penetrations, and ballistic barriers)?

3.

>Z4 Cause materials or equipment to be placed or installed within the Security Isolation Zone?

4.

11 Affect (block, move, or alter) security lighting by adding or deleting lights, structures, buildings, or temporary facilities?

5.

6.

7.

8.

© Modify or otherwise affect primary or secondary power supplies to access control equipment, intrusion detection equipment, other security equipment, or to the Central Alarm Station or the Secondary Alarm Station?

9.

11124 Modify or otherwise affect the facility's security-related signage or land vehicle barriers, including access roadways?

10.

013 Modify or otherwise affect the facility's telephone or security radio systems?

Page 8 of 10 IV.

$0.59 EVALUATION License Amendment Determination Does the proposed Change being evaluated represent a change to a method of evaluation

If "No," answer No all questions below.

Does the proposed Change:

1.

Result in more than a minimal increase in the frequency of occurrence of an accident

No BASIS:

LI-101-01, Rev. 6 50.59 REVIEW FORM A loss of normal feedwater flow accident is evaluated in FSAR Section 15.2.2.5

. This accident is classified as an infrequent incident and is defined as ua reduction in feedwater flow to the steam generators when operating at power, without a corresponding reduction in steam flow from the steam generators". A loss of normal feedwater flow with an active failure in the Steam Bypass System is evaluated in FSAR Section 15.2.3.2, and is classified as a limiting fault.

The Condensate and Feedwater System (CFWS) is described in FSAR Section 10.4.7. Section 10.4.7.3 states that "The Condensate and Feedwater Systems are capable of operation at full load with one out of three condensate pumps out of service or all three heater drain pumps out of service. The C WS are capable of operation at partial load with one steam generator feedwater pump out of service or one heater string out of service". Under EPU conditions, the CFWS will no longer support full load operation with 2 or 3 heater drain pumps out of service.

In fact, the loss of either 2 or 3 heater drain pumps under EPU will likely result in the loss of both feedwater pumps unless changes to the feedwater pump low suction pressure trip logic are made.

To address this issue, Westinghouse ran several analytical cases to vary the Main Feedwater Pump (MFP) low suction trip setpoint and time delays for a loss of either 2 car 3 heater drain pumps at EPU full power conditions, using success criteria of preventing a trip of both feedwater pumps and preventing a plant trip due to low steam generator level. The analyses confirm new feedwater pump low suction pressure trip setpoints, instrument reset values and trip time delays that are necessary to satisfy the success criteria

. The results of the analyses are documented in Westinghouse DAR-OA-05-4 and CN-SEE-04-77 which provide the basis for the changes made by ER-W3-2004-0602-000.

ER-W3-2004-0602-000 modifies the feedwater pump trip logic by changing the low suction pressure instrument trip setpointslreset values and by changing the trip delay timer settings to provide a delay between tripping of the first feedwater pump and tripping of the second feedwater pump. This combination of changes to the feedwater pump low suction pressure trip logic prevents a loss of heater drain pumps from causing a reduction in feedwater flow without a corresponding reduction in steam flaw. The logic changes result in tripping of one feedwater pump after only a short time delay, thereby initiating a turbine runback signal

. Turbine runback provides the 'corresponding reduction in steam flow', and prevents tripping of the second feedwater pump by allowing adequate time for suction pressure to recover, prior to expiration of the trip time delay.

Therefore, the changes made by ER-W3-2004-0602-000 ensure that implementation of EPU will not result in more than a minimal increase in the frequency of occurrence of a loss of normal feedwater flow accident as previously evaluated in the FSAR.

BASIS:

50.59 REVIEW FORM Result in more than a minimal increase in the likelihood of occurrence of a malfunction of a El Yes structure, system, or component important to safety previously evaluated in the FSAR?

No The proposed change does not affect the design or operation of any SSCs that are important to safety.

The instrumentation affected by this change is provided as an equipment protection feature for the Main Feedwater Pumps. Neither the affected instrumentation nor the Main Feedwater Pumps are classified as

`important to safety' in the Waterford 3 licensing and design basis. Therefore, the likelihood of a malfunction of an SSC important to safety is not affected by these changes, and the changes do not result in more than a minimal increase in the likelihood of occurrence of a malfunction of a structure, system, or component important to safety previously evaluated in the FSAR.

3.

Result in more than a minimal increase in the consequences of an accident previously 0

. Yes evaluated in the FSAR?

g No The proposed changes do not change, degrade, or prevent actions described or assumed in an accident discussed in the FSAR. Likewise, they do not affect the function of equipment designed to control the release of radioactive material and do not result in a new pathway for release of radioactive material.

Additionally, the changes will not affect onsite dose in a way that restricts access to vital areas or impedes mitigating actions. Therefore, the change will not result in more than a minimal increase in the consequences of an accident previously evaluated in the FSAR.

4.

Result in more than a minimal increase in the consequences of a malfunction of a structure,

No BASIS:

The proposed changes do not affect the design or operation of any SSCs that are important to safety. The changes do not cause a greater reliance to be placed on a specific SSC to perform a safety function, nor do they affect the design or operation of any SSC important to safety. Therefore, the change will not result in more than a minimal increase in the consequences of a malfunction of a structure, system, or component important to safety previously evaluated in the FSAR.

5.

Create a possibility for an accident of a different type than any previously evaluated in the

No BASIS:

The proposed changes are associated with low suction pressure trip logic of the feedwater pumps. The FSAR defines a loss of normal feedwater flow accident as "a reduction in feedwater flow to the steam generators when operating at power, without a corresponding reduction in steam flow from the steam generators." The changes made by this ER provide the necessary reduction in steam flow by tripping one feedwater pump early in the scenario to cause a turbine runback to occur. The loss of feedwater pump scenarios evaluated in the FSAR are not being changed, and the effects of the modification are bounded by existing FSAR analyses. Therefore, there are no accidents of a different type created by these changes.

6.

Create a possibility for a malfunction of a structure, system, or component important to safety

BASIS.

OR No The proposed changes do not affect the design or operation of any SSCs that are important to safety. As a result, the change does not introduce any new system interactions, does not introduce any new failure modes for associated equipment, and does not create the possibility for a malfunction of a structure, system, or component important to safety with a different result than any previously evaluated in the FSAR.

7.

Result in a design basis limit for a fission product barrier as described in the FSAR being

LI-101_01, Rev. 6 No

Rage 10 of 10 BASIS :

50.59 REVIEW FORM The proposed changes are associated with low suction pressure trip logic of the feedwater pumps. The changes do not affect any design basis limits for fission product barriers including fuel cladding, RCS boundary, or containment pressure, as described in the FSAR.

8.

Result in a departure from a method of evaluation described in the FSAR used in establishing

No BASIS:

The proposed changes are limited to changes to the feedwater pump low suction pressure trip logic. The changes do not affect any methods of evaluation used in analyses that demonstrate that design basis limits of fission product barriers are met, methods of evaluation used in FSAR safety analyses to demonstrate that consequences of accidents do not exceed regulatory limits, or methods of evaluation for other analyses that demonstrate intended design functions will be accomplished. Therefore, the changes will not result in a departure from a method of evaluation described in the FSAR used in establishing the design bases or in the safety analyses.

If any of the above questions is checked "YES", obtain NRC approval prior to implementing the change by initiating a change to the Operating License in accordance with NM M Procedure ENS-Ll-113.

LI-101-01, Rev. 6

ML061280090

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