W3F1-2020-0033, (Waterford 3) - Response to U. S. Nuclear Regulatory Commission Request for Additional Information Regarding License Amendment Request to Revise Technical Specification 3/4.8.1, A.C. Sources Operating

(Waterford 3) - Response to U. S. Nuclear Regulatory Commission Request for Additional Information Regarding License Amendment Request to Revise Technical Specification 3/4.8.1, A.C. Sources Operating

ML20150B638
Person / Time
Site:	Waterford
Issue date:	05/29/2020
From:	Gaston R Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
W3F1-2020-0033
Download: ML20150B638 (8)

Text

Entergy Operations, Inc.

1340 Echelon Parkway Jackson, MS 39213 Tel 601-368-5138 Ron Gaston Director, Nuclear Licensing 10 CFR 50.90 W3F1-2020-0033 May 29, 2020 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Response to U. S. Nuclear Regulatory Commission Request for Additional Information Regarding License Amendment Request to Revise Technical Specification 3/4.8.1, "A.C. Sources Operating" Waterford Steam Electric Station, Unit 3 (Waterford 3)

NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38

References:

1. Entergy Operations, Inc. (Entergy) letter to U. S. Nuclear Regulatory Commission (NRC), "License Amendment Request to Revise Technical Specification 3.8.1.1," W3F1-2019-0073, (ADAMS Accession Number ML19297H543), dated October 24, 2019

2. NRC letter to Entergy, " Waterford Steam Electric Station, Unit 3 -

Request for Additional Information Regarding License Amendment Request to Revise Technical Specification 3/4.8.1, "A.C. Sources Operating" (EPID L-2020-LLA-0230)," (ADAMS Accession No. ML20086M385), dated April 1, 2020 By letter dated October 24, 2019 (Reference 1), Entergy requested an amendment to revise Technical Specification 3/4.8.1 (A.C. Sources - Operating) for Waterford Steam Electric Station, Unit 3 (Waterford 3).

By letter dated April 1, 2020 (Reference 2), the NRC staff informed Entergy that they have reviewed the license amendment request and have determined that additional information is required to complete the review. A clarification call between the NRC and Entergy was previously held on March 26, 2020.

The additional information requested by the NRC in Reference 2 is provided in the Enclosure to this letter.

W3F1-2020-0033 Page 2 of 2 This letter contains no new regulatory commitments.

Should you have any questions or require additional information, please contact Paul Wood, Regulatory Assurance Manager, at 504-464-3786.

I declare under penalty of perjury, that the foregoing is true and correct. Executed on May 29, 2020.

Respectfully, Ron Gaston RWG/mmz

Enclosure:

Response to NRC Request for Additional Information cc: NRC Region IV Regional Administrator NRC Senior Resident Inspector - Waterford Steam Electric Station, Unit 3 NRR Project Manager Louisiana Department of Environmental Quality, Office of Environmental Compliance

Enclosure W3F1-2020-0033 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION

W3F1-2020-0033 Enclosure Page 1 of 5 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION Regulatory Basis Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(b) states, in part, that Each license authorizing operation of a production or utilization facility of a type described in § 50.21 or § 50.22 will include technical specifications. The technical specifications will be derived from the analyses and evaluation included in the safety analysis report, and amendments thereto, submitted pursuant to § 50.34.

The NRC also considered the following General Design Criteria of 10 CFR Part 50, Appendix A, General Design Criteria for Nuclear Power Plants.

General Design Criterion (GDC) 17, Electric power systems, states in part, that:

An onsite electric power system and an offsite electric power system shall be provided to permit functioning of structures, systems, and components important to safety.

GDC 34, Residual heat removal, states that:

A system to remove residual heat shall be provided. The system safety function shall be to transfer fission product decay heat and other residual heat from the reactor core at a rate such that specified acceptable fuel design limits and the design conditions of the reactor coolant pressure boundary are not exceeded.

GDC 35, Emergency core cooling, states that:

A system to provide abundant emergency core cooling shall be provided.

The system safety function shall be to transfer heat from the reactor core following any loss of reactor coolant at a rate such that (1) fuel and clad damage that could interfere with continued effective core cooling is prevented and (2) clad metal-water reaction is limited to negligible amounts.

Suitable redundancy in components and features, and suitable interconnections, leak detection, isolation, and containment capabilities shall be provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available) the system safety function can be accomplished, assuming a single failure.

GDC 38, Containment heat removal, states that:

A system to remove heat from the reactor containment shall be provided.

The GDC also requires, in part, that containment capabilities shall be provided to assure that for onsite electric power system operation, (assuming offsite power is not available) the system safety function can be accomplished, assuming a single failure.

W3F1-2020-0033 Enclosure Page 2 of 5 NRC Generic Letter 89-10, Safety-Related Motor-Operated Valve [MOV] Testing and Surveillance (ADAMS Accession No. ML031150300), dated June 28, 1989, requested that licensees consider the performance of MOVs during degraded voltage conditions.

Request for Additional Information Request 1 For the emergency diesel generator lube oil pump and jacket water pump on the emergency diesel generator skid, and the fuel oil transfer pump, discuss whether or not the proposed diesel generator under-frequency limit of 59.7 hertz (Hz) has any effect on the flow rates for these pumps.

Entergy Response The EDG lube oil pump is driven by the diesel engine. The LAR proposes an increase of the EDG steady state under-frequency limit of 58.8 Hz to 59.7 Hz which is a conservative change.

Since generator frequency is directly related to engine speed this requires engine speed to be controlled in a tighter band. Therefore, engine driven pump performance is improved.

The change in EDG lube oil pump speed due to a change in generator frequency (i.e., engine speed) from the nominal 60 Hz case, will cause a minimal decrease in pump flow. A standby lube oil pump is available which will start automatically if lube oil pressure drops below a set pressure. Therefore, the proposed diesel generator under-frequency limit of 59.7 Hz will not affect operation of the EDG Lube Oil System.

The Main Jacket Water Pump is a centrifugal pump driven off the diesel crankshaft via a chain and sprocket. The LAR proposes an increase of the EDG steady state under-frequency limit of 58.8 Hz to 59.7 Hz which is a conservative change. Since generator frequency is directly related to engine speed this change requires engine speed to be controlled in a tighter band.

Therefore, engine driven pump performance is improved.

The change in Main Jacket Water Pump speed due to a change in generator frequency (i.e.,

engine speed) from the nominal 60 Hz case, is accommodated by the pump rating as well as operation of the jacket water temperature control valve which will open to maintain jacket water temperature.

The diesel oil transfer pumps pump fuel from the fuel oil storage tank to replenish the diesel feed tank. The LAR proposes an increase of the EDG steady state under-frequency limit of 58.8 Hz to 59.7 Hz which is a conservative change which will result in improved pump performance by increasing the minimum allowed pump speed.

Operation of the diesel oil transfer pumps pump at the proposed under-frequency limit of 59.7 Hz would cause delivered flow to be lower compared to the nominal 60 Hz case based on the pump affinity laws; however, this is well within the margin available. Calculation ECM91-001 (EDG Fuel Oil Transfer Pump Recirculation & Discharge Flow, Revision 4) determines that the minimum flow to the diesel oil feed tanks is 47 gpm. The maximum required flow from the diesel oil feed tanks is less than 15 gpm, so the required flow to the feed tanks is less than

W3F1-2020-0033 Enclosure Page 3 of 5 15 gpm. Potential EDG underfrequency is not accounted for in this calculation because of the large margin between required flow and delivered flow.

Request 2 Section 3.2, Current Licensing Basis and Evaluation, of the LAR states, in part, that the diesel generator under-frequency limit of 59.7 Hz is needed to ensure that the minimum low-pressure safety injection and high-pressure safety injection safety analysis delivery assumptions are met.

The proposed changes to the surveillance requirements identify considerations in the performance of pumps within the high-pressure safety injection and the low-pressure safety injection systems, as documented in Waterford 3 Condition Report CR-WF3-2008-5183 (Reference 12 of the LAR).

The effects of diesel generator frequency variations and the performance of all pumps associated with emergency core cooling systems were described in the LAR and reviewed for conformance with associated regulatory requirements (e.g., GDC 17, 34, 35, 38). However, the NRC staff notes that performance capabilities of other equipment, such as MOVs, heaters, and fans associated with emergency core cooling systems or related heating and ventilation systems are also susceptible to voltage and frequency variations. This equipment in these systems is not discussed in the LAR. Typically, licensees evaluated the performance of MOVs during degraded voltage conditions in their responses to NRC Generic Letter 89-10.

Therefore, provide a discussion of how all of the safety-related equipment that could be impacted by the voltage limits and frequency variations proposed in the LAR, such as MOVs, heaters, fans, or pumps, was evaluated for conformance using the assumptions in the accident analyses for Waterford 3. Provide confirmation that the voltage limits and frequency variations proposed in the LAR will not adversely impact the assumptions in the safety analysis.

Entergy Response The LAR proposes an increase of the EDG steady state under-voltage limit of 3740 volts to 3920 volts which is a conservative change.

The minimum voltage of 3920 volts envelopes and protects the degraded voltage relay trip setpoint of 3875 volts and its reset value of 3915 volts. The degraded voltage relay trip setpoint is shown in Waterford 3 Technical Specification Table 3.3-4. The 3920V ensures safe operations of all safety related electrical loads. Additionally, it assures the minimum voltage output of the EDG is adequate before the safety related loads are connected and the degraded voltage relays reset.

Specifically, an analysis of the Waterford 3 electrical distribution system has determined the proper degraded voltage relay setpoint by considering voltage drop during a 100% Load Rejection or Loss of Coolant Accident (LOCA) scenario. These two scenarios provide the most conservative avenue for a voltage analysis during a sustained degraded voltage condition. The analysis shows with the degraded voltage relay trip setpoint at 3875 volts, all safety related buses at the 4.16KV, 480V, and 120V would have sufficient voltage to operate all safety related equipment. The conclusion from this voltage analysis supports the TS Change in the Amendment 74 to the Waterford 3 Operating License dated August 24, 1992 which is consistent with the change proposed in this LAR.

W3F1-2020-0033 Enclosure Page 4 of 5 The LAR proposes an increase of the EDG steady state under-frequency limit of 58.8 Hz to 59.7 Hz which is a conservative change.

A review of the under-frequency on the electrical performance of motors, static uninterruptible power supplies (SUPS), battery chargers, transformers, and heaters that are fed by the EDG during a LOCA coincident with a LOOP was performed. For motors, specification 1564.283 (Class 1E 4KV Motors) requires that motors are capable of starting at 90-110% of rated voltage at rated frequency. When motors are started from the EDG, the motor terminal voltage may dip to 75% of rated voltage with a simultaneous drop in frequency to 95% of normal. Restoration of EDG voltage and frequency are at 90% and 98%, respectively. Similarly, Class 1E 460V (ref.

Specification 1564.264) motors comply with the requirements of NEMA standards. NEMA MG-1 Section 12.44 states that alternating current motors shall operate successfully under running conditions at rated load with a variation in the frequency +/-5%. For safety related Static Uninterruptible Power Supplies (SUPS), specification DES-E-029 states +/-5% of rated frequency. For battery chargers, specification 1564.280B states +/-5% of rated frequency. For transformers, the proposed under-frequency is within the acceptable and normal range for electrical equipment, including power transformers. Specification 1564.261B (Station Service Transformers) specifies an operating frequency for the transformers at a minimum of 58.8 Hz.

Heaters are a resistive load and hence, the proposed change in frequency has negligible impact if any, to the heaters. Therefore, the proposed under-frequency value is within the span of frequency where the motors, SUPS, battery chargers, transformers, and heaters can operate.

A review of the under-frequency on the mechanical performance of motor-operated equipment (pumps, fans, and valves) fed by the EDG during a LOCA coincident with a LOOP was performed. The applicable affinity equations were reviewed to determine the effect of the proposed change.

Pump flow is directly proportional to pump speed (i.e., motor frequency) while head is proportional to the square of speed. The LAR proposes an increase of the EDG steady state under-frequency limit of 58.8 Hz to 59.7 Hz which is a conservative change and will result in improved pump performance by increasing the minimum allowed pump speed which results in improved flow and head while only minimally reducing net positive suction head (due to increased flow).

The allowance of a lower EDG frequency limit of 59.7 Hz will result in a reduction of 0.5% pump flow and 1.0% pump head as compared to the nominal 60 Hz case. Available net positive suction head will have a minor increase due to the reduction in pump flow as compared to the nominal 60 Hz case. These changes are minimal and well within existing margins.

MOV stroke time is directly proportional to frequency. The LAR proposes an increase of the EDG steady state under-frequency limit of 58.8 Hz to 59.7 Hz which is a conservative change and will improve MOV performance. Compared to the based 60 Hz case operation at 59.7 Hz will lower MOV stroke time by 0.5%. This is a minimal change which is well within existing margins.

Fan flow is also directly proportional to frequency. The LAR proposes an increase of the EDG steady state under-frequency limit of 58.8 Hz to 59.7 Hz which is a conservative change and will result in improved fan performance by increasing the minimum allowed fan speed which results in improved flow. Compared to the based 60 Hz case operation at 59.7 Hz will lower flow by 0.5% which is a minimal change and is well within existing margins.

W3F1-2020-0033 Enclosure Page 5 of 5 Existing pump flow, pump head, fan flow and motor operated valve stroke time margins were reviewed. The proposed minimum allowed EDG steady state under-frequency limit of 59.7 Hz will present a minimal change in pump, MOV and fan performance from the nominal 60 Hz case which is well within existing margins.