ML18316A034

Response to Request for Additional Information: Proposed Changes to Technical Specification 3.8.1 Actions A.3 and D.3 to Extend the Offsite Circuit Inoperable Completion Times from 72 Hours to 14 ...

ML18316A034
Person / Time
Site:	Calvert Cliffs
Issue date:	11/12/2018
From:	David Gudger Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML18316A034 (18)

Text

200 Exelon Way Exelon Generation ~, Kennett Square, PA 19348 www.exeloncorp.com 10 CFR 50.90 November 12, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 Renewed Facility Operating License Nos. DPR-53 and DPR-69 NRC Docket Nos. 50-317 and 50-318

Subject:

Response to Request for Additional Information Proposed Changes to Technical Specification 3.8.1 Actions A.3 and D.3 to Extend the Offsite Circuit Inoperable Completion Times from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days on a One-Time Basis on each Unit

References:

1. Letter from D. P. Helker (Exelon Generation Company, LLC) to U.S.

Nuclear Regulatory Commission, "License Amendment Request-Proposed Changes to Technical Specification 3.8.1 Actions A.3 and D.3 to Extend the Offsite Circuit Inoperable Completion Times from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days on a One-Time Basis on each Unit," dated August 23, 2018 (ML18235A199).

2. Email from Michael Marshall (NRC to Frank Mascitelli and Rick Villar (Exelon) RAI, dated October 29, 2018(ML18302A357).

By letter dated August 23, 2018 (Reference 1), Exelon Generation Company, LLC (Exelon) requested an amendment to the Renewed Facility Operating License Nos. DPR-53 and DPR-69 for Calvert Cliffs Nuclear Power Station, Units 1 and 2, respectively. The proposed amendment requested two one-time use extensions to Technical Specifications (TS) 3.8.1 (AC Sources-Operating) Actions A.3 and D.3 Completion Times {CT) for an inoperable offsite circuit from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to fourteen (14) days in order to allow for the future installation and tie in of a new 13 kV service transformer during the 2019 Unit 2 Refuel Outage and the 2020 Unit 1 Refuel Outage. The tie in of the new service transformer cannot be accomplished within the current CT of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

The NRC staff reviewed the information provided and identified the need for additional information to complete their evaluation of the amendment request. The final request for additional information (RAI) was sent from the NRC to Exelon by electronic mail message on October 29, 2018 (ADAMS Accession No. ML18302A357 (Reference 2). The NRC and Exelon agreed to a response within 20 days (November 18, 2018). to this letter provides a restatement of the RAI questions followed by our responses. Attachment 2 provides the additional marked up TS associated with response to RAl#2.

U.S. Nuclear Regulatory Commission Response to Request for Additional Information RAI Response to LAR for TS 3.8.1 Actions A.3 and D.3 Docket Nos. 50-317 and 50-318 November 12, 2018 Page 2 contains the Technical Evaluation associated with response to RAI #4. contains the requested temperature data for the OC DG.

Exelon has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, that were previously provided to the NRG in Attachment 1 of the Reference 1 letter. Exelon has concluded that the information provided in this response does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92. In addition, Exelon has concluded that the information in this response does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.

There are no regulatory commitments in this response.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"

paragraph (b), Exelon is notifying the State of Maryland of this RAI response by transmitting a copy of this letter and its attachments to the designated State Official.

If you have any questions or require additional information, please contact Frank J. Mascitelli at 610-765-5512.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 121h day of November 2018.

Respectfully, i<<,_JT +Jv David T. Gudger Director, Licensing and Regulatory Affairs Exelon Generation Company, LLC Attachments:

1. Response to Request for Additional Information, "Proposed Changes to Technical Specification 3.8.1 Actions A.3 and D.3 to Extend the Offsite Circuit Inoperable Completion Times from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days on a One-Time Basis on each Unit"

2. Proposed TS Markup 3.8.1.D.3

3. Technical ECP-18-000496, Technical Evaluation for the Long-Term Degradation Occurring in the OC2 DG Exhaust Gas Temperatures, dated August 15, 2018

4. Requested OC DG Temperature Data cc: USNRC Region I, Regional Administrator USNRC Project Manager, CCNPP USNRC Senior Resident Inspector, CCNPP D. A. Tancabel, State of Maryland

ATTACHMENT 1 License Amendment Request Calver Cliffs Nuclear Power Plant, Units 1 and 2 Docket Nos. 50-317 and 50-318 Response to Request for Additional Information Proposed Changes to Technical Specification 3.8.1 Actions A.3 and D.3 to Extend the Offsite Circuit Inoperable Completion Times from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days on a One-Time Basis on each Unit

Response to Request for Additional Information Attachment 1 Proposed Changes to TS 3.8.1 Actions A.3 and D.3 Page 1 of 7 Docket Nos. 50-317 and 50-318 By letter dated August 23, 2018 (Agencywide Document Access Management System (ADAMS) Accession No. ML18235A199), Exelon Generation Company, LLC (Exelon, the licensee) submitted a license amendment request (LAR) proposing to revise Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (Calvert Cliffs) Technical Specifications (TS) to permit one-time extension to the completion times (CTs) for two required actions in Section 3.8.1, "AC

[Alternating Current] Sources-Operating," of the Calvert Cliffs TS. The one-time extensions up to 14 days would apply to Required Action A.3, "Restore required offsite circuit to OPERABLE status," and Required Action D.3, "Declare CREVS [Control Room Emergency Ventilation System] and CRETS [Control Room Emergency Temperature Control System] supported by the inoperable offsite circuit inoperable."

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in the LAR and has determined that additional information is needed to complete its review. In an email dated October 29, 2018 to Exelon (ADAMS Accession No. (ML18302A357), the NRC provided a Final Request for Additional Information (RAI) seeking clarification of certain issues related to the submittal. The RAI was discussed during follow-up teleconferences on October 17 and 29, 2018, and it was agreed that a response would be provided within 20 days from the date of October 29, 2018 (November 18, 2018).

REQUEST FOR ADDITIONAL INFORMATION The requirements in Title 10 of the Code of Federal Regulations (10 CFR), Section 50.63, "Loss of All Alternating Current Power," requires that each light-water-cooled nuclear power plant to be able to withstand and recover from a station blackout (SBO) (i.e., loss of the offsite electric power system concurrent with reactor trip and unavailability of the onsite emergency alternating current electric power system) of a specified duration. The 10 CFR 50.63 requirements provide assurance that necessary operator actions can be performed and that necessary control room -

area equipment will be functional under the expected environmental conditions during and following a station blackout, thereby ensuring that the core will be cooled and appropriate containment integrity will be maintained.

In its LAR, the licensee states that overall configuration changes to the plant electrical systems have been evaluated in accordance with the guidance of, NUREG-0800 Branch Technical Position (BTP) 8-8, "Onsite (Emergency Diesel Generators) and Offsite Power Sources Allowed Outage Time Extensions," (ADAMS Accession No. ML113640138). Also, the licensee evaluated the additional effects to CREVS and CRETS from one inoperable offsite source.

RAI #1 QUESTION Section B of BTP 8-8 states, in part:

Multi-unit sites that have installed a single AAC [alternate alternating current] power source for SBO cannot substitute it for the inoperable diesel when requesting AOT

[allowed outage time] extensions unless the AAC source has enough capacity to carry all LOOP [loss of offsite power] loads to bring the unit to a cold shutdown as a substitute for the EOG [emergency diesel generator] in an extended AOT and carry all SBO loads for the unit that has an SBO event without any load shedding.

Response to Request for Additional Information Attachment 1 Proposed Changes to TS 3.8.1 Actions A.3 and D.3 Page 2 of 7 Docket Nos. 50-317 and 50-318 Subsection 4.2c of the LAA, which provides the explanation of how Calvert Cliffs meets the above BTP 8-8 requirements but does not appear to discuss whether the AAC power source requires load shedding described in BTP 8-8.

Please provide a discussion of whether the AAC power source requires load shedding.

RESPONSE

Calvert Cliffs operating procedures for the alternate alternating current (AAC) power source (OC Diesel Generator (DG), also referred to as the SBO Diesel) do not require any manual load shedding for plant shutdown from a Loss of Offsite Power (LOOP) condition. If a LOOP or Station Blackout (SBO) occurs, the undervoltage relays on the plant 4 kV emergency safety-related buses send a signal to the Engineered Safety Features Actuation System (ESFAS) to trip the required loads from these buses. This automatic load shed operation is powered from plant batteries and is independent of a loss of offsite power. After the operator selects the 4 kV emergency safety-related bus to be powered, the OC DG is manually started and the operator verifies the automatic load shed breakers are open and the OC DG is at proper voltage and frequency. The OC DG output breaker is then closed and the applicable ESFAS shutdown sequencer is manually initiated to automatically sequence the loads required for plant shutdown or for the SBO unit. This ESFAS automatic sequencing is also powered from plant batteries and independent from offsite power.

The load profile used for this LAA response uses the same shutdown sequence load profile from the Emergency Diesel Generator (EOG) load calculation for the 4 kV emergency safety-related buses. This load profile does not credit any additional load shedding. The two maximum-loaded emergency safety-related buses (4kV bus 11 and 24) were used for conservatism to obtain maximum load. Thus, there is no load shedding requirement in the operation of the AAC source.

RAI #2 QUESTION Section 8 of BTP 8-8 states, in part that The TS must contain Required Actions and CTS to verify that the supplemental AC [alternating current] source is available before entering extended AOT ." Section 4.1 of the LAA states, in part, that "During each of these refueling outages CREVS/CRETS alternate power can be provided by either the SBO Diesel or the SMECO line."

In the LAA, the proposed change for TS 3.8.1 Action D.3 does not appear to include the required action(s) and CT(s) to verify that the AAC sources (i.e., SMECO line and SBO DG) are available before entering extended CT.

Please provide a discussion of how the proposed change is consistent with above BTP 8-8 guidance.

RESPONSE

To provide consistency with Section 8 of BTP 8-8, which requires Required Actions and Completion Times for the supplemental AC source, Exelon is proposing Limiting Conditions for Operation when both the SBO DG and SMECO Line are simultaneously not available. If

Response to Request for Additional Information Attachment 1 Proposed Changes to TS 3.8.1 Actions A.3 and D.3 Page 3 of 7 Docket Nos. 50-317 and 50-318 during the 14-day extended Completion Time period, a Condition arises that both the SBO DG and SMECO Line are unavailable a Required Action is established to restore one of the AC supplemental sources (either the SBO DG OR SMECO Line) to available status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Mode 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The proposed TS 3.8.1.D.3 is contained in Attachment 2 and supersedes previous proposed TS wording in Reference 1.

RAI #3 QUESTION Section 4.1, "Station Electrical Power Configuration during the 14-day CT Period," of the LAA states, in part that "During each of these refueling outages CREVS/CRETS alternate power can be provided by either the SBO Diesel or the SMECO line." Section B of BTP 8-8 states, in part:

Multi-unit sites that have installed a single AAC power source for SBO cannot substitute it for the inoperable diesel when requesting AOT extensions unless the AAC source has enough capacity to carry all LOOP loads to bring the unit to a cold shutdown as a substitute for the EOG in an extended AOT and carry all SBO loads for the unit that has an SBO event without any load shedding.

Subsection 4.2c of the LAA, which provides the explanation of how Calvert Cliffs meets the above BTP 8-8 guidance, further states, in part:

It is noted that the SBO Diesel currently has an equipment issue with its OC2 turbocharger. A special test run and Technical Evaluation (Reference 24) concluded that the SBO Diesel will maintain greater than continuous 4,766.3 kW load with engine room temperatures averaging 75.4 °F, as would be expected during the months of January through March, based upon historical ambient (outside) and engine room temperatures.

Please provide a summary description of the special test run and the technical evaluation. In the summary description include the following:

a. OC2 turbo exhaust temperature alarm setpoint.

b. OC2 turbo exhaust temperature during the special test run.

c. Average OC2 turbo exhaust temperature for the months of January to March from 2014 to present.

d. OC2 cylinder temperature alarm setpoint.

e. OC2 cylinder temperature during the special test run.

f. Average OC2 cylinder temperature for the months of January to March from 2014 to present.

Response to Request for Additional Information Attachment 1 Proposed Changes to TS 3.8.1 Actions A.3 and D.3 Page 4 of 7 Docket Nos. 50-317 and 50-318

g. Discuss whether the OC2 turbo exhaust or OC2 cylinder temperatures exceed alarm setpoint during the special test run or for the months of January to March from 2014 to present.

RESPONSE

A summary description of OC DG current condition and special test run data performed on August 9, 2018 is contained within the Technical Evaluation ECP-18-000496 (Attachment 3). Requested data is also provided in the attached spreadsheet in Attachment 4. Please note that the requested average OC2 turbo exhaust temperature data from the months of January to March from 2014 to present is not available as it is not a logged point documented by Operations during scheduled OC DG runs.

a. OC2 turbo exhaust temperature alarm setpoint - 919°F +/- 13°F

b. OC2 turbo exhaust temperature during the special test run - Data is not available

c. Average OC2 turbo exhaust temperature for the months of January to March from 2014 to present - Data is not available

d. OC2 cylinder temperature alarm setpoint - 1135 °F (1122 to 1148 °F uncertainty band) from any one of 16 cylinder outlets)

e. OC2 cylinder temperature during the special test run - Contained in Attachment 4

f. Average OC2 cylinder temperature for the months of January to March from 2014 to present - Contained in Attachment 4 RAI #4 QUESTION Section 4.1, "Station Electrical Power Configuration during the 14-day CT Period," of the LAR states, in part that "During each of these refueling outages CREVS/CRETS alternate power can be provided by either the SBO Diesel or the SMECO line." Subsection 4.2c of the LAA further states, in part "It is noted that the SBO Diesel currently has an equipment issue with its OC2 turbo charger."

Regulatory Guide 1.9, "Application and Testing of Safety-Related Diesel Generators in Nuclear Power Plants," (ADAMS Accession No. ML070380553) in describing the reliability of the EDGs (including, the SBO diesel generator (DG)), states, in part:

The design of the emergency diesel generators (EDGs) should also incorporate high operational reliability, and this high reliability should be maintained throughout their lifetime by initiating a reliability program that is designed to monitor, improve, and maintain reliability. Increased operational reliability can be achieved through appropriate testing and maintenance, as well as an effective root cause analysis of all emergency diesel generator failures.

Response to Request for Additional Information Attachment 1 Proposed Changes to TS 3.8.1 Actions A.3 and D.3 Page 5 of 7 Docket Nos. 50-317 and 50-318 The NRC staff notes that the SBO DG is proposed to be an alternate power supply for the CREVS and CRETS if the EOG is inoperable. As part of reviewing the power supply for the CREVS and CRETS, the staff notes that there is no information describing the impact of the equipment issue with respect to its the reliability of the SBO DG. This impact may affect whether the SBO DG is an adequate alternate power source for the CREVS and CRETS when the EOG inoperable.

Please provide a description of how equipment issue impacts the SBO DG reliability with respect to the power source to the CREVS and CRETS.

RESPONSE

The OC DG is monitored and maintained in accordance with ER-AA-440, "Emergency Diesel Generator (EOG) Reliability Program."

Based on a review of the Corrective Action Review Program (CAP) from year 2014 to present, the reliability of the OC DG is 100%. There were no documented start demand failures for scheduled periodic testing during this approximate five-year period.

The equipment issue described in Reference 1 has had no impact on OC DG reliability based upon not having any failures for any valid start demands per Regulatory Guide 1.155, "Station Blackout." The current equipment issue condition described could impact the OC DG design capacity of 5,400 kW.

The available OC DG turbo charger and cylinder exhaust temperature condition has been evaluated (Attachment 3). The evaluation has identified a long-term degradation occurring in the OC2 DG exhaust gas temperatures. This degradation is resulting in lowered margin to alarm setpoints during fully loaded runs. The evaluation substantiated that despite this degradation, the OC DG is able to meet the expected 4,766.3kw load for the SBO event described in Reference 1, with the additional establishment of the compensatory action limit of 92 °F ambient (outside) air temperature, during the expected February 2019 and 2020 14-day extended Completion Times. The OC DG maximum expected load is 4,766.3 kW and is conservatively based on the highest loaded emergency safety-related bus from each unit (4 kV buses 11 and 24). The OC DG can adequately and individually support being the power source to the CREVS and CRETS, which has an expected total load of 415.4 kW.

RAI 5 and 6 QUESTIONS The NRC staff reviews the human performance aspects of LARs using the guidance in Standard Review Plan Chapter 18 and NUREG-1764 Rev. 1, "Guidance for the Review of Changes to Human Actions" (ADAMS Accession No. ML072640413). In accordance with the generic risk categories established in Appendix A to NUREG-1764, actions to recover offsite power after a LOOP and actions involving risk-important systems are potentially risk-important. Due to the risk importance, the NRC staff will perform a Level II human factors review per the guidance in Section 4 of NUREG-1764, Rev. 1.

The LAR states that the FLEX DGs will be used as additional defense-in-depth to support the proposed 14 day CT. However, the LAR does not state how the FLEX DGs will be used to support the proposed 14 day CT in relation to how the FLEX DGs were designed to support

Response to Request for Additional Information Attachment 1 Proposed Changes to TS 3.8.1 Actions A.3 and D.3 Page 6 of 7 Docket Nos. 50-317 and 50-318 mitigation of beyond design-basis external events (BDBEEs) in accordance with Order EA 049, "Order Modifying Licenses with Regard to Requirements for Mitigating Strategies for Beyond Design-Basis External Events," (ADAMS Accession No. ML12054A735). The NRC staff requests the following information to determine whether the use of the FLEX DGs to support the proposed CT is feasible and reliable.

RAI #5 QUESTION Describe any differences between deployment, staging, timing, and use of the FLEX DGs to support the proposed 14 day CT and to meet the requirements of Mitigating Strategies Order EA-12-049?

RESPONSE

Upon further review Exelon has determined that no prestaging of the FLEX Diesels (DG) will occur. The FLEX Diesels will be used in accordance with existing approved procedures that implement and support Mitigating Strategies Order EA-12-049. No new activities (deployment, staging, timing and use of FLEX DGs) are being proposed for this LAR's third level of defense-in-depth that have not already been NRC reviewed to support Mitigating Strategies Order EA-12-049.

During the extended 14-day Completion Time, should an SBO event occur, procedures EOP-1 or 2 (Reference 1 Attachment 1, References 12 and 13) would be used and if the SBO condition exceeded one hour (i.e., both SBO Diesel and SMECO Line are unavailable) an ELAP (Extended Loss of AC Power) would be declared. The FLEX Guidelines (FSG) would then be utilized to address the Beyond Design Bases External Event (BDBEE). FSG-5, "Initial Assessment and FLEX Equipment Staging," (Reference 1, Attachment 1, Reference 4) has the major action and time frames that would be implemented for activities to be completed using the FLEX DGs. Selected 480 VAC buses would be powered within approximately seven hours, but there is are no specific actions in the FSG to energize CREVS/CRETS at that time. Should CREV/CRETS be needed, the 480 VAC buses feeding CREVS/CRETS would be given priority restoration. In addition, FSG-15, "Alignment for Area Cooling," has actions to align temporary ventilation to the Control Room within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> using the 5,500 W Pramac FLEX Diesel Generator and 2,000 CFM blower.

RAI #6 QUESTION If the FLEX DGs will used differently to support the proposed CT than to support Mitigating Strategies Order EA-12-049, answer the following:

a. Will the FLEX DGs remain available and protected from all BDBEEs while being used to support the proposed 14 day CT? If the FLEX DGs will not remain available and protected from all BDBEEs, how will the site meet its allowed unavailability times for FLEX (NEI 12-06, Rev. O or Rev. 2 or exception taken in FLEX Implementation Plan and evaluated in FLEX SE)?

b. What procedural and administrative control(s) changes were made to direct staging and use of the FLEX DGs in support of the proposed 14 day CT as opposed to the mitigation of BDBEEs?

Response to Request for Additional Information Attachment 1 Proposed Changes to TS 3.8.1 Actions A.3 and D.3 Page 7 of 7 Docket Nos. 50-317 and 50-318

c. How was training modified to address the use of the FLEX DGs in the context of supporting the proposed 14 day CT as opposed to the mitigation of BDBEEs?

d. What validation was performed to ensure that the administrative controls are effective and that the FLEX DGs can be connected in the time required to support the proposed 14 day CT as opposed to the mitigation of BDBEEs?

RESPONSE

The FLEX DGs will not be used differently to support the proposed CT than to support Mitigating Strategies Order EA-12-049.

ATTACHMENT 2 License Amendment Request Calver Cliffs Nuclear Power Plant, Units 1 and 2 Docket Nos. 50-317 and 50-318 Proposed TS Markup 3.8.1.D.3 3.8.1-5

AC Sources-Operating 3.8.1 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME D. LCO 3.8.1.c offsite ----------- NOTE------------

circuit inoperable. Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems-Operating," when Condition D is entered with no AC power source to a train.

D.1 Perform SR 3.8.1.1 or 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> SR 3.8.1.2 for required OPERABLE AND offsite circuit(s).

Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter D.2 Declare, CREVS or 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from CRETS with no offsite discovery of no power available offsite power to inoperable when the one train redundant CREVS or concurrent with CRETS is inoperable. inoperability of redundant required feature(s)

D.3 Declare CREVS and 72 hourfci CRETS supported by the inoperable off site circuit inoperable.

CALVERT CLIFFS - UNIT 1 3.8.1-5 Amendment No. 274 CALVERT CLIFFS - UNIT 2 Amendment No. 251

INSERT 1 Or 14 days, once during each applicable 2019 and 2020 Refuel Outage, for the connection of the new P-13000 Service Transformer.

Prior to entry into the 14-day Completion Time, the OC DG and the SMECO 69 kV Line shall be verified available. During the 14-day Completion Time, the OC DG and SMECO 69 kV Line shall be verified available once per shift.

If both the OC DG and SMECO 69 kV Line become un-available during the 14-day Completion Time, either the OC DG or the SMECO 69 kV Line shall be restored to available status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or the Unit shall be brought to MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

ATTACHMENT 3 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50*352 and 50*353 Technical ECP-18*000496, Technical Evaluation for the Long*Term Degradation Occurring in the OC2 DG Exhaust Gas Temperatures, dated August 15, 2018

TECHNICAL EVALUATION Page 1of2 ECP No.: Rev. No.: O ECP-18-000496 Reason for Evaluation:

Strategic Engineering has reviewed past available OC Diesel Generator turbo charger and cylinder exhaust temperature data and has identified a long-term degradation occurring in the OC2 DG exhaust gas temperatures. This degradation is resulting in lowered margin to alarm setpoints during fully loaded runs. This evaluation will substantiate that despite this degradation, the OC DG is able to meet the commitment of 4766.3kw load for the Electrical Distribution Reliability Improvement Project License Amendment Request submittal.

Detailed Evaluation of Problem/Changes:

The_OC2 Turbo exhaust temperature alarmed during a scheduled 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> loaded run of the OC DG. This resulted in Operators taking alarm response manual actions and lowering the load.

The specific alarm received was fed from 0-TIS-10651 and alarmed at 915F (Alarm Window SL-130 in the QC Control Room). Its alarm setpoint is 919F +/- 13F. Upon alarm validation by plant operators, OC DG load was lowered from 5000kw to 2400kw. After approximately 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at lowered temperatures, OC DG load was raised from 2400kw to 3000kw. The OC DG was subsequently run successfully for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> at 4200kw, which would meet STP 08 Acceptance Criteria, and at 3600kw for the remaining 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> to demonstrate Functionality of the OC DG.

Engine Room temperature during the time of the higher load was 90F.

As a result of this issue, focused troubleshooting was performed to determine the cause of the elevated temperatures and nothing abnormal was noted. On 6/7/2018 the OC DG was operated for 5.75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br /> at 5020kw-5097kw load. Engine Room temperature during this run ranged from 81.9F to 86.3F with outside air temperature ranging from 68.3F to 74.0F. At no time during this run were any alarm or operational limits reached.

Further troubleshooting on 8/9/18 revealed that the OC DG could be loaded to 5200kw for greater than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> with engine room temperature range from 95-107F without alarm limits being reached. Ambient (outside) temperature during this run ranged from 79-88F. It should be noted that the OC DG Engine room temperature is maintained by 4 fans that cycle on, one at a time, in 1OF increments starting at a room temperature of 75F.

Review of previous data reveals a correlation of OC DG Exhaust temperature to QC DG Engine Room temperature, with a ratio of 1.375:1.

QC DG run data has been reviewed for DG Room temperature data vs Average Exhaust temperature for the months of Jan-March from 2014 to present. This has indicated an average room temperature of 75.4F with a high of 89F and a low of 70.5F, and average OC2 Cylinder temperature of 961 F. At no time did these temperatures reach alarm response limits.

Additionally, historical weather data for Lusby MD shows average high temperature of 44F, 47F and 55F for the months of January to March, respectively.

TECHNICAL EVALUATION Page 2 of 2 ECP No.: Rev. No.: O ECP-18-000496 Conclusion/Findings Based upon review of previous data and temperature correlations, it is reasonable to expect that the OC DG will maintain >4766.3kw load with Engine Room temperatures averaging 75.4F as would be expected during the months of January through March, based upon historical ambient and engine room temperatures as noted above. System Manager recommends a limit of 92F ambient (outside) air temperature to credit the OC DG for LAA commitment based upon these findings, which accounts for historical average of 14F difference between outside air temperature and OC DG Engine Room temperature, as well as operation at the maximum allowed tolerance for turbo exhaust gas temperature.

ATTACHMENT 4 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 Requested OC DG Temperature Data

DatefTime of Room Temp OCDG Average Cylinder KW Outside Air Room Exhaust Temp OC1 Load Temp engine I OC2 engine 01/11/2014 1138 85F 952/963 5112 01/11/2014 1217 89F 970/979 5040 02/08/2014 1605 74F 946/952 5140 02/08/2014 1634 75F 961/968 5190 01/11/2015 0203 72F 942/960 5150 01/11/2015 0210 72F 948/965 5150 02/12/2015 0023 75.5F 951/976 5025 02/12/2015 0034 74.3F 954/948 5025 03/14/2015 2326 80.4F 938/949 4891 03/15/2015 0000 82.4F 937/953 4862 01 /19/2016 1445 71.3F 931/961 oos 02/12/2016 1313 72.6F 937/962 5000 02/12/2016 1355 74.7F 942/966 5000 03/03/2016 2346 70.5F 924/943 oos 03/04/2016 0015 72.3F 932/950 oos 02/09/2017 2257 72F 938/960 5000 02/09/2017 2316 73.2F 943/965 5000 02/07/2018 1112 75.2F 954/973 4900 02/07/2018 1147 71.5F 942/969 4960 06/07/2018 1041 81.9F 956/985 5040 68.3F 06/07/2018 1113 82.3F 958/989 5020 68.6F 06/07/2018 1201 82.2F 962/992 5082 70.6F 06/07/2018 1258 83.0F 965/997 5039 70.9F 06/07/2018 1357 84.5F 969/999 5089 72.9F 06/07/2018 1500 86.1F 971/1004 5040 73.9F 06/07 /2018 1545 86.3F 977/1010 5097 74.0F 08/09/2018 1000 103.6F 975/983 5200 80.6F 08/09/201 8 11 00 104.8 988/1013 5200 82.4F 08/09/2018 1200 106.1 988/1017 5225 83.4F 08/09/2018 1300 107 991/1017 5200 84.2F