ML19325C128

License Amendment Request - Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program

ML19325C128
Person / Time
Site:	Calvert Cliffs
Issue date:	11/21/2019
From:	David Gudger Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML19325C128 (13)

Text

Exelon Generation ~.

November 21, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Calvert Cliffs Nuclear Power Plant, Units 1 and 2 200 Exelon Way Kennett Square. PA 19348 www exeloncorp com 10 CFR 50.90 Renewed Facility Operating License Nos. DPR-53 and DPR-69 Docket Nos. 50-317 and 50-318

Subject:

License Amendment Request-Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program In accordance with 1 O CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (Exelon) is submitting a request for amendment to the Technical Specifications (TS).

The proposed amendment will extend the reactor coolant pump (RCP) motor flywheel examination, to an interval not to exceed 20 years. The proposed amendment is consistent with the Pressurized Water Reactor Owners Group (PWROG) Topical Report (TR), PWROG-17011-NP, Revision 2, "Update for Subsequent License Renewal: WCAP-14535A, 'Topical Report on Reactor Coolant Pump Flywheel Inspection Elimination,' and WCAP-15666-A,

'Extension of Reactor Coolant Pump Motor Flywheel Examination."'

This letter contains two (2) Attachments as listed below.

There are no regulatory commitments contained in this letter. Exelon requests approval of the proposed license amendment by October 31, 2020, with the amendment being implemented within 60 days.

These proposed changes have been reviewed by the Plant Operations Review Committee and approved in accordance with Nuclear Safety Review Board procedures.

In accordance with 10 CFR 50.91, "Notice for public comment; state consultation," a copy of this application, with appropriate attachments, is being provided to the designated State Official.

License Amendment Request Change to Surveillance Requirement 3.5.3.1 Docket Nos. 50-317 and 50-318 November 21, 2019 Page2 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 21 51 day of November 2019.

If you should have any questions regarding this submittal, please contact Enrique Villar at 610-765-5736.

Respectfully, David T. Gudger Sr. Manager - Licensing Exelon Generation Company, LLC Attachments: 1. Evaluation of Proposed Change

2. Marked-up Technical Specifications Page cc:

NRG Regional Administrator, Region I NRG Senior Resident Inspector, CCNPP NRG Project Manager, NRR, CCNPP D. A. Tancabel, State of Maryland

ATTACHMENT 1 EVALUATION OF PROPOSED CHANGE

Subject:

Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedence 4.3 No Significant Hazards Consideration 4.4 Conclusions

6.0 REFERENCES

Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program Page 1 of 7 1.0

SUMMARY

DESCRIPTION This evaluation supports a request to amend Renewed Operating Licenses DPR-53 and DPR-69 for Calvert Cliffs Nuclear Power Plant (CCNPP) Unit Nos. 1 and 2 by revising Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program.

The proposed change adds a statement that would extend the reactor coolant pump (RCP) motor flywheel examination interval to an interval not to exceed 20 years. This proposed change is consistent with Pressurized Water Reactor Owners Group (PWROG) transmitted Topical Report (TR), PWROG-17011-NP, Rev 2, "Update for Subsequent License Renewal:

WCAP-14535A, 'Topical Report on Reactor Coolant Pump Flywheel Inspection Elimination,"'

and WCAP-15666-A, "Extension of Reactor Coolant Pump Motor Flywheel Examination."

The topical report was approved by the Nuclear Regulatory Commission (NRG) on September 11, 2019.

2.0 DETAILED DESCRIPTION Calvert Cliffs Units 1 and 2 Technical Specification 5.5.7 currently states:

"5.5.7 Reactor Coolant Pump Flvwheel Inspection Program This program shall provide for the inspection of each reactor coolant pump flywheel per the recommendations of regulatory position c.4.b of Regulatory Guide 1.14, Revision 1, August 1975."

It is noted that Regulatory Position C.4.b of Regulatory Guide 1.14 (Reference 1) states in part that:

"lnservice inspection should be performed for each flywheel as follows:

1. An in-place ultrasonic volumetric examination of the areas of higher stress concentration at the bore and keyway at approximately 3-year intervals, during the refueling or maintenance shutdown coinciding with the inservice inspection schedule as required by Section XI of the ASME code.

2. A surface examination of all exposed surfaces and complete ultrasonic volumetric examination at approximately 10-year intervals, during the plant shutdown coinciding with the inservice inspection schedule as required by Section XI of the ASME code."

Calvert Cliffs meets Regulatory Position C.4.b (1) by conducting this inspection on every RCP motor flywheel every second refueling outage. Calvert Cliffs meets Regulatory Position C.4.b (2) by conducting this inspection on every RCP motor flywheel every fifth refueling outage.

Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program Page 2 of 7 Exelon proposes to revise Technical Specification 5.5.7 as follows:

"5.5.7 Reactor Coolant Pump Flywheel Inspection Program This program shall provide for the inspection of each reactor coolant pump flywheel per the recommendations of Regulatory Position C.4.b of Regulatory Guide 1.14, Revision 1, August 1975.

In lieu of Regulatory Position C.4.b(1) and C.4.b(2), a qualified in-place UT examination over the volume from the inner bore of the flywheel to the circle one-half of the outer radius or a surface examination (MT and/or PT) of exposed surfaces of the removed flywheels may be conducted at an interval not to exceed 20 years."

Note that an administrative change is made to the first paragraph that changes the term "regulatory position c.4.b" to "Regulatory Position C.4.b" to be consistent with Reference 1.

=

Background===

At Calvert Cliffs, each unit's Reactor Coolant System (RCS) consists of two reactor coolant loops and each reactor coolant loop contains two RCPs. The RCPs ensure an adequate cooling flow rate by circulating large volumes of primary coolant water at high temperature and pressure through the RCS. Each RCP is powered by an air cooled, three-phase induction motor which employs a flywheel to increase its coast down time in the event of a loss of electrical power to the motor. During normal power operation the RCP motor flywheel possesses sufficient kinetic energy to produce high energy missiles in the event of flywheel failure. To help provide assurance of the RCP motor flywheel integrity, flywheel examinations are currently performed in accordance with the recommendations contained in Reference 1.

Throughout the industry, over an extended period of time, these inspections have been conducted and have identified no service-induced flaws which would have affected RCP motor flywheel integrity. On the basis of this inspection record and the contributing factors of savings in inspection cost and personnel radiation exposures, the industry has initiated several technical analyses to justify the extension of the RCP motor flywheel inspection frequencies.

The Westinghouse Owners Group submitted Westinghouse Owners Group (WOG) WCAP-14535A, Topical Report on Reactor Coolant Pump Flywheel Inspection Elimination, November 1996," (WCAP-14535A) (Reference 2). The justification for WCAP-14535A was based on an engineering analysis, that utilized fracture mechanics to eliminate the need for RCP motor flywheel inspections for Westinghouse plants. Although the NRC accepted the evaluation methodology used in Reference 2, the NRC did not allow the complete elimination of the RCP motor flywheel inspections. In lieu of a complete elimination of testing, the NRC agreed that the plants to which the topical report was applicable to, could either conduct a qualified in-place ultrasonic examination {UT) over the volume from the inner bore of the RCP motor flywheel to the circle of one-half the outer radius or conduct a surface Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program Page 3 of 7 examination [magnetic particle inspection (MT) or liquid penetrant test (PT}] of exposed surfaces defined by the volume of the disassembled flywheels at an interval not to exceed 1 o years.

The NRC issued a Safety Evaluation Report (SER) for WCAP-14535A in September 12, 1996, allowing an extension in the examination frequency from 40 months to 1 O years.

Subsequently Technical Specifications Task Force (TSTF)-421, "Revision to RCP Flywheel Inspection Program (WCAP-15666)," was submitted to NRC. TSTF 421 was based on the results of WCAP-15666-A, "Extension of Reactor Coolant Pump Motor Flywheel Examination, October 2003," (Reference 3) that justified extending the RCP motor flywheel examination to an interval not to exceed 20 years. Extension of the allowed examination interval was desired in order to align the RCP motor flywheel examination interval with the extended RCP refurbishment schedules. The NRC approved TSTF-421-A.

WCAP-15666-A consists of a deterministic analysis and a probabilistic change in risk assessment to justify the extension. The change-in-risk assessment was used to demonstrate that the extension in examination interval resulted in an increase in core damage frequency and large early release frequency that are below the guidelines for acceptably small changes listed in U.S. Nuclear Regulatory Commission, Regulatory Guide 1.17 4, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, July 1998" (Reference 4).

NRC approval of WCAP-15666-A was limited to specific Westinghouse RCP motor flywheels for the applicable plants evaluated.

Although the Calvert Cliffs Units 1 and 2 RCP motors and flywheel were manufactured by Westinghouse, they were not included as one of the plants in WCAP-15666-A. The Calvert Cliffs Units 1 and 2 RCP motor flywheels assembly consists of two discs bolted together and keyed to the shaft above the motor. The RCP motor flywheels are made of A533 vacuum-degassed material which is the same material as the RCP motor flywheels that were evaluated in WCAP-15666-A.

By letter dated January 28, 2019, the Pressurized Water Reactor Owners Group (PWROG) transmitted Topical Report (TR) PWROG-17011-NP, Rev 2, "Update for Subsequent License Renewal: WCAP-14535A, 'Topical Report on Reactor Coolant Pump Flywheel Inspection Elimination,"' and WCAP-15666-A, "Extension of Reactor Coolant Pump Motor Flywheel Examination," (Reference 5).

The purpose of TR PWROG-17011-NP, Revision 2, is to extend the applicability of WCAP-14535A (Reference 2) and WCAP-15666-A (Reference 3) to the subsequent period of extended operation (SPEO), i.e., from 60 years of operation to 80 years of operation. The original inspection frequency for RCP flywheels was specified in Regulatory Guide (RG) 1.14, Revision 1, "Reactor Coolant Pump Flywheel Integrity," dated August 1975 (Reference 1 ).

PWROG-17011-NP, Revision 2 includes, and it is applicable to the Calvert Cliffs Units 1 and 2 RCPs and, thus, extends the applicability of the previously NRC approved WCAP-14535A and 15666-A to Calvert Cliffs Units 1 and 2.

Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program Page 4 of 7 The NRC issued the Final Safety Evaluation (FSE) for PWROG-17011 on September 11, 2019. The TR contains no limitation or condition for the Westinghouse RCP flywheels, considering that the flywheel operating, and material data used in the generic analyses have already been examined twice and accepted during plant-specific applications using WCAP-14535A and WCAP-15666-A. The NRC FSE for PWROG-17011-NP Revision 2 states:

"However, because the flywheel operating, and material data used in the generic analyses for Calvert Cliffs in the TR are new and need to be confirmed by the licensee:

the normal operating speed for the RCP flywheels is 900 rpm the design limiting speed for the RCP flywheels is 1125 rpm the maximum overspeed following a design basis LOCA is 1368 rpm it is appropriate to use 70 °F as the medium temperature for design limiting event (Table 3-2) in the PFM analysis "

The limitations and conditions in the NRC FSE are satisfied by the discussions contained in the Calvert Cliffs Updated Final Safety Analysis Report Section 4.1.3.3.1 - Reactor Coolant Pump Flywheel (Reference 7).

Note that the TR requires applicants of this TR to confirm that 6000 cycles for 80 years of operation is applicable on a plant-specific basis. This confirmation shall be made in all SLR applications to fulfill the TR requirement. However, this TR requirement is not applicable to Calvert Cliffs Units 1 and 2, since an SLR application is not be pursued at this time. If an SLR application is pursued in the future, this TR requirement will be confirmed.

In conclusion, the complete technical evaluation justifying the applicability of the 20-year RCP flywheel inspection interval to Calvert Cliffs Units 1 and 2 is contained in PWROG-17011-NP-A, Revision 2 (Reference 6), and its associated NRC FSE.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria The Atomic Energy Commission's proposed General Design Criterion 4, "Missile Protection,"

requires that 'protection for engineered safety features shall be provided against dynamic effects and missiles that might result from plant equipment failures.'

Regulatory Guide 1.14, Revision 1, "Reactor Coolant Pump Flywheel Integrity" describes a method acceptable to the NRC staff of implementing this requirement with regard to minimizing the potential for failures of the RCP motors flywheels in light water-cooled power reactors.

The analyses documented in References 3 and 5 provide the technical basis to extend the examination frequency for the RCP motor flywheels out to a maximum of 20 years and satisfy Regulatory Guide 1.17 4 risk criteria as being an acceptable change.

Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program Page 5 of 7 Precedence This proposed change is consistent to the change contained in TSTF-421-A which was approved by the NRC. However, TSTF-421-A was only applicable to plants with Westinghouse designed nuclear steam supply systems. Calvert Cliffs Units 1 and 2, while not a Westinghouse designed nuclear steam supply systems plant, has Westinghouse RCPs. However, as discussed above, the Calvert Cliffs Units 1 and 2 RCPs were evaluated in PWROG-17011-NP-A, which includes the applicability of WCAP-15666-A, upon which TSTF-421-A was based.

4.3 No Significant Hazards Consideration Calvert Cliffs Nuclear Power Plant (Calvert Cliffs) is proposing a change to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program. The proposed change would extend the allowed examination interval of the RCP flywheels out to a maximum of 20 years. The proposed change also includes a minor administrative change that capitalizes words in Technical Specification 5.5.7 in order to be consistent with the Nuclear Regulatory Commission's Regulatory Guide 1.14.

1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?

No.

Calvert Cliffs' proposed change to the reactor coolant pump (RCP) motor flywheel examination frequency does not change the response of the plant to any accidents. The RCP will remain highly reliable and the proposed change will not result in a significant increase in the risk of plant operation. Given the extremely low failure probabilities for the RCP motor flywheel during normal/accident conditions and the extremely low probability of loss-of-coolant accident/loss of off-site power, and even assuming a conditional core damage probability of 1.0 (complete failure of safety systems), the core damage frequency (CDF) and change in risk would still not exceed the Nuclear Regulatory Commission's (NRCs) acceptance guidelines contained in NRC Regulatory Guide 1.174 (<1.0E-6 per year). Even considering the uncertainties involved in this evaluation, the risk associated with the postulated failure of an RCP motor flywheel is not significant. Even if all four RCP motor flywheels are considered in the bounding plant configuration case, the risk is still acceptably low. Since the evaluation results for CDF and the conservative assumption that failure of the RCP motor flywheel is assumed to result directly in core damage and also a large early release (CDF=LERF), calculations were not performed for the LERF. The CDF and LERF results are below the NRC's LERF acceptance guidelines.

The proposed change does not adversely affect accident initiators or precursors nor alter the design assumptions, conditions, or configuration of the facility, or the manner in which the plant is operated and maintained. The proposed change does not alter or prevent structures, systems, and components from performing their intended function to mitigate the consequences of an initiating event within the assumed acceptance limits. The proposed change does not affect the source term, containment isolation, or radiological release assumptions used in evaluating the radiological consequences of an accident previously evaluated. Further, the proposed change does not increase the types or amounts of Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program Page 6 of 7 radioactive effluent that may be released offsite, nor significantly increase individual or cumulative occupational/public radiation exposures. The proposed change is consistent with the safety analysis assumptions and resultant consequences.

The proposed administrative word change has no impact on the probability or consequence of an accident previously evaluated.

Therefore, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?

No.

The proposed change in the RCP motor flywheel examination frequency does not involve any change in the design or operation of the RCP. The change to examination frequency does not change any existing accident scenarios, nor create any new or different accident scenarios. The change does not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed) or a change in the methods governing normal plant operation. In addition, the change does not impose any new or different requirements or eliminate any existing requirements. The change does not alter any assumptions made in the safety analysis. The proposed change is consistent with the safety analysis assumptions and current plant operating practice.

The proposed administrative word change does not create a new or different kind of accident.

Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed amendment involve a significant reduction in a margin of safety?

No.

The proposed change in the RCP motor flywheel does not alter the manner in which safety limits, limiting safety system settings, or limiting conditions for operation are determined. The safety analysis acceptance criteria are not impacted by this change. The proposed change will not result in plant operation in a configuration outside of the design basis. The calculated impact on risk is insignificant and meets the acceptance criteria contained in NRC Regulatory Guide 1.17 4. There are no significant mechanisms for inservice degradation of the RCP flywheel.

The proposed administrative word change does not result in any change to a margin of safety.

Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Revision to Technical Specification 5.5.7, Reactor Coolant Pump Flywheel Inspection Program Page 7 of 7 Based on the above, Exelon concludes that the proposed amendment does not involve a significant hazards consideration under the standards set forth in 1 O CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

Calvert Cliffs review has determined that the proposed amendment would change an examination requirement. However, the proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 1 O CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

6.0 REFERENCES

1)

U.S. Nuclear Regulatory Commission, Regulatory Guide 1.14, Reactor Coolant Pump Flywheel Integrity, Revision 1, August 1975

2)

Westinghouse Owners Group WCAP-14535A, Topical Report On Reactor Coolant Pump Flywheel Inspection Elimination, November 1996

3)

Westinghouse Owners Group WCAP-15666-A, Extension of Reactor Coolant Pump Motor Flywheel Examination, October 2003

4)

U.S. Nuclear Regulatory Commission, Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis, July 1998

5)

Pressurized Water Reactor Owners Group (PWROG) transmitted Topical Report (TR) PWROG-17011-NP, Revision 2, "Update for Subsequent License Renewal:

WCAP-14535A, 'Topical Report on Reactor Coolant Pump Flywheel Inspection Elimination,"' and WCAP-15666-A, "Extension of Reactor Coolant Pump Motor Flywheel Examination," PA-MSC-1500

6)

U.S. Nuclear Regulatory Commission, Final Safety Evaluation for Pressurized Water Reactor Owners Group Topical Report, PWROG-17011-NP, Revision 2 Report, "Update for Subsequent License Renewal: WCAP-14535A, 'Topical Report on Reactor Coolant Pump Flywheel Inspection Elimination,"' and WCAP-15666-A, "Extension of Reactor Coolant Pump Motor Flywheel Examination," September 11, 2019

7)

Calvert Cliffs UFSAR, 4.1.3.3.1, Reactor Coolant Pump Flywheel.

ATTACHMENT 2 MARKED-UP TECHNICAL SPECIFICATIONS PAGES AND INSERT 1

Programs and Manuals 5.5 5.5 Programs and Manuals 5.5.6 Concrete Containment Tendon Surveillance Program 5.5.7 5.5.8 5.5.9 This program provides controls for monitoring any tendon degradation in pre-stressed concrete containments, including effectiveness of its corrosion protection medium, to ensure containment structural integrity.

The program shall include baseline measurements prior to initial operation.

The Tendon Surveillance Program, inspection frequencies, and acceptance criteria shall be in accordance with Section XI, Subsection IWL of the ASME Boiler and Pressure Vessel Code and applicable addenda as required by 10 CFR 50.SSa, as amended by relief granted in accordance with 10 CFR 50.55a(a)(3).

The provisions of SR 3.0.3 are applicable to the Tendon Surveillance Program inspection frequencies.

Reactor Coolant Pump Flywheel Inspection Program

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DELETED Steam Generator (SG) Program A Steam Generator Program shall be established and implemented to ensure that SG tube integrity is maintained.

In addition, the Steam Generator Program shall include the following:

a.

Provisions for condition monitoring assessments.

Condition monitoring assessment means an evaluation of the "as found" condition of the tubing with respect to the performance criteria for structural integrity and accident induced leakage.

The "as found" condition refers to the condition of the tubing during an SG inspection outage, as determined from the inservice inspection results or by other means, prior to CALVERT CLIFFS - UNIT 1 CALVERT CLIFFS - UNIT 2 5.5-6 Amendment No. 320 Amendment No. 298

INSERT 1 This program shall provide for the inspection of each reactor coolant pump flywheel per the recommendations of Regulatory Position C.4.b of Regulatory Guide 1.14, Revision 1, August 1975.

In lieu of Regulatory Position C.4.b(1) and C.4.b(2), a qualified in-place UT examination over the volume from the inner bore of the flywheel to the circle one-half of the outer radius or a surface examination (MT and/or PT) of exposed surfaces of the removed flywheels may be conducted at an interval not to exceed 20 years.