ML17094A670

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Issue MNS-SLC-16.9.15. Snubbers
ML17094A670
Person / Time
Site: Mcguire, McGuire  Duke energy icon.png
Issue date: 03/15/2017
From:
Duke Energy Carolinas
To:
Office of Nuclear Reactor Regulation
References
Download: ML17094A670 (13)
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Text

Date: 3/15/2017 Distribution: Duke Energy Document Transmittal #: TR-NUC-MC-005543

1. Boyer, Robert P
2. Carroll, Michael E DOCUMENT TRANSMITTAL FORM

Purpose:

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3. Gardner, Troy R
  • r - - - - - - - - - - - - - - - - - - - - - - - - 1 Released By:

Facility: MCGUIRE NUCLEAR STATION Duke Enemy

4. Mc Ginnis, Vickie L
5. OPS HUMAN PERFORMANCE - SUBJECT 13225 Hagers ferry Road Issue MNS-SLC-16.9.15. SNUBBERS Document Management
6. OPS TRNG.MGR.
7. RESIDENT NRC INSPECT MG02DM
8. SERV BLDG FILE ROOM - Huntersville. NC 28078
10. USNRC Page 1of1 1 2 3 4 5 6 7 8 9 10 FYIIE FYIIE FYIIE FYIIE R&AIE PRINTILP FYIIE R&AIE R&AIE

Snubbers 16.9.15 16.9 AUXILIARY SYSTEMS 16.9.15 Snubbers COMMITMENT All snubbers shall be FUNCTIONAL.

NOTE----------------------------------------------

Sn ubbers installed on non-safety systems may be excluded from these requirements provided their failure or the failure of the system on which they are installed would not have an adverse affect on any safety-related system.

APPLICABILITY At all times for snubbers located on systems required OPERABLE.

REMEDIAL ACTIONS

NOTE------------------------------------------------------------------

Conditions A, B, and C are applicable to "seismic snubbers" as defined in the BASES.

McGuire Units 1 and 2 16.9.15-1 Revision 156

Snubbers 16.9.15 CONDITION REQUIRED ACTION COMPLETION TIME A. ----------NOTE------------ A.1.1 Verify that at least one Immediately If the opposite train of AFW train (including a the associated system minimum set of supporting becomes inoperable for equipment required for its reasons not related to successful operation) not snubbers while in associated with the non-Condition A, exit functional snubber(s), or Condition A and enter alternative core cooling Condition C. method, is OPERABLE.

AND One or more seismic snubbers associated A.1.2 Verify the opposite train of -Immediately with one train of a the associated system is multiple train system operable, if a multiple train non-functional for system.

maintenance or testing and the opposite train of AND the associated system is operable. A.1.3 Log the affected system(s) Immediately for tracking in eSOMS.

OR AND One or more seismic snubbers associated A.1.4 Enter the applicable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> with a single train ACTIONS for the train or system non-functional component associated with for maintenance or the non-functional testing. snubber(s).

OR A.2 Declare the supported Immediately system inoperable.

(continued)

McGuire Units 1 and 2 16.9.15-2 Revision 156

Snubbers 16.9.15 McGuire Units 1 and 2 16.9.15-3 Revision 156

Snubbers 16.9.15 CONDITION REQUIRED ACTION COMPLETION TIME

c. One or more seismic C.1.1 Verify that at least one Immediately snubbers associated AFW train (including a with one train of a minimum set of supporting multiple train system equipment required for its non-functional for successful operation) not maintenance or testing. associated with the non-functional snubber(s), or AND alternative core cooling method, is OPERABLE.

The opposite train of the associated system is AND inoperable for reasons not related to snubbers. C.1.2 --------------Note-------------

If the reason for the non-functionality of the snubber or the inoperability of the opposite train of the associated system is due to planned work, the risk assessment must be completed prior to starting work.

Initiate a qualitative risk Immediately assessment of the resulting configuration.

AND C.1.3 Enter the applicable 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from failure ACTION for the train or to meet the component associated with COMMITMENT the non-functional snubber.

OR C.2 Declare the supported Immediately system inoperable D. Required Action and D.1 Enter the applicable Immediately associated Completion ACTIONS for the train or Time of Condition A, B, component associated with or C not met. the non-functional snubber.

(continued)

McGuire Units 1 and 2 16.9.15-4 Revision 156

Snubbers 16.9.15 CONDITION REQUIRED ACTION COMPLETION TIME E. One or more snubbers E.1 Enter the applicable Immediately with any significant non- ACTIONS for any affected seismic loads non- 'system(s) and functional for component(s) that are maintenance or testing. determined to be inoperable.

OR E.2 Perform an engineering Prior to removing the evaluation to determine the snubber from effect of the non-functional service.

snubber on the operability of the associated system.

F. One or more snubbers F.1 Perform an engineering 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> non-functional due to evaluation to determine the actual failure of the effect of the non-functional snubber or failure to snubber on the operability meet test acceptance of the associated system.

criteria.

McGuire Units 1 and 2 16.9.15-5 Revision 156

Snubbers 16.9.15 TESTING REQUIREMENTS

NOTES---------------------------------------------------

Sn ubber testing and inspection requirements shall be performed in accordance with the ASME OM Code, Subsections ISTA and ISTD in compliance with 10 CFR 50.55a. These requirements are implemented by administrative procedure AD-EG-MNS-1618 (Reference 14).

Administrative Procedure AD-EG-MNS-1618 "McGuire Nuclear Station Snubber Program Plan" is incorporated by reference into SLC 16.9.15 and is therefore subject to the control of 10 CFR 50.59.

TEST FREQUENCY TR 16.9.15.1 Perform visual inspection for inaccessible and accessible In accordance with snubbers in accordance with Administrative Procedure Administrative AD-EG-MNS-1618. Procedure AD-EG-MNS-1618.

TR 16.9.15.2 --------------------------------NOTE---------------------------------

ln case of a severe dynamic event, mechanical snubbers in that system which experienced the event shall be inspected during the refueling outage to assure that the mechanical snubbers have freedom of movement and are not frozen up Perform an inspection to determine if there has been a 18 months, in severe dynamic event for systems which have the accordance with potential for a severe dynamic event. Administrative Procedure AD-EG-MNS-1618.

TR 16.9.15.3 Perform functional testing for snubbers in accordance 18 months, in with Administrative Procedure AD-EG-MNS-1618. accordance with Administrative Procedure AD-EG-c MNS-1618.

TR 16. 9. 15 .4 --------------------------------NOTE---------------------------------

The parts replacement shall be documented and the documentation shall be retained for the duration of the unit operating license.

Verify that the service life of snubbers has not been 18 months, in exceeded or will not be exceeded prior to the next accordance with scheduled surveillance inspection. Administrative Procedure AD-EG-MNS-1618.

McGuire Units 1 and 2 16.9.15-6 Revision 156

Snubbers 16.9.15

'BASES This commitment contains requirements for plant snubbers. There are snubbers installed for seismic loads only (i.e., those loads induced by seismic events, "earthquakes") and snubbers that are installed for the combined effects of both seismic loads and non-seismic loads (i.e.,

those dynamic loads induced by operational events such as steamhammer, waterhammer, LOCAs, and pipe rupture). Thus for the purpose of this commitment, there are two categories of snubbers:

1) snubbers which have only seismic loads, and snubbers which have both seismic and non-seismic loadings, but Engineering has determined that the non-seismic loads are insignificant and do not effect the operability of the associated system. Since the seismic loads are those of significance, these snubbers are termed "Seismic Snubbers" in this commitment; and
2) snubbers which have both seismic and non-seismic loadings and Engineering has determined that the non-seismic loads are significant and do effect the operability of the associated system.

The Remedial Actions for each of these snubber categories are discussed below. Remedial Action F.1 and the Testing Requirements of this commitment apply to both categories of snubbers. The programmatic requirements for the visual inspection and functional testing of snubbers do not meet the criteria in 10 CFR 50.36(c)(2)(ii) for inclusion in the plant TS, and as such, are appropriate for control by this commitment and are the same for both categories of snubbers.

The snubber requirements of SLC 16.9.15 were originally located in the Technical Specifications. The Nuclear Regulatory Commission (NRC) authorized the use of these requirements, while located in Technical Specifications, as an acceptable alternative to the requirements of the ASME Code, 1989 Edition,Section XI, Article IWF-5000 (References 3, 4).

Subsequently, rulemaking per 10 CFR 50.55a was revised to require all snubber examination and testing to be performed in accordance with the ASME OM Code, Subsection ISTD.

Therefore, the ASME OM Code, Subsection ISTD is invoked by rulemaking and the third interval relief requests (References 3, 4) are no longer valid.

All snubbers are required to be FUNCTIONAL to ensure that the structural integrity of the Reactor Coolant System and all other safety-related systems is maintained during and following a seismic or other event initiating dynamic loads. Snubbers excluded from this inspection program are those installed on nonsafety-related systems and then only if their failure or failure of the system on which they are installed, would have no adverse effect on any safety-related system.

Snubbers removed from service for any reason cannot be considered FUNCTIONAL since it is not connected to the supported system or component.

McGuire Units 1 and 2 16.9.15-7 Revision 156

Snubbers 16.9.15 BASES (continued)

Seismic Snubbers Seismic snubbers are installed primarily to address loads resulting from a seismic event.

However, some seismic snubbers do have other non-seismic loads, but these other loads have been determined to have an insignificant effect on the operability of the associated system, as determined by Engineering. If used, TS LCO 3.0.8 contains the OPERABILITY requirements for seismic snubbers.

LCO 3.0.8 establishes conditions under which systems are considered to remain capable of performing their intended safety function(s) when associated seismic snubbers are not capable of providing their associated support function(s). This LCO states that the supported system is not considered to be inoperable solely due to one or more of these snubbers not being capable of performing their associated support function(s). Thus, any affected supported LCO(s) are not required to be declared not met solely for this reason, if risk is assessed and managed.

This is appropriate because a limited length of time is allowed for inspection, testing, maintenance, or repair of one or more of these snubbers not capable of performing their associated support function(s), remedial actions are specified in this commitment, and the low probability of a seismic event concurrent with an event that would require operation of the supported system occurring while the snubber(s) are not capable of performing their associated support function(s), and as applicable, due to the availability of the redundant train of the supported system.

If the allowed time expires and the seismic snubber(s) are unable to perform their associated support function(s), the affected supported system's LCO(s) must be declared not met and the Conditions and Required Actions entered in accordance with LCO 3.0.2.

Snubbers with Both Seismic and Significant Non-Seismic Loads If the affected snubber has more than one function, one of which MUST be seismic loads, then LCO 3.0.8 may be applied. However, there must be a deterministic analysis that demonstrates that the supported system can still perform its function for the non-seismic load(s). For example, if the affected snubber has support functions for both seismic loads and LOCA loads (i.e., blowdown loads), then only that LOCA load is considered deterministically to determine if the system is OPERABLE. If the supported TS system is OPERABLE for the non-seismic loads, then LCO 3.0.8 may be applied to the seismic loads. Otherwise, LCO 3.0.8 may not be applied and the FUNCTIONALITY requirements are contained in this commitment.

Remedial Actions - A Remedial Action A applies when one or more seismic snubbers associated with one train of a multiple train system and the opposite train of the associated system is operable or associated with a single train system are non-functional for maintenance or testing, thus are not capable of providing their associated support function(s). This commitment allows up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore the seismic snubber(s) before declaring the supported system inoperable, provided: 1) there is an immediate determination that at least one AFW train (including a minimum set of supporting equipment required for its successful operation) not associated with the non-functional snubber(s), or alternative core cooling method (e.g., feed and bleed, firewater system or "aggressive secondary cooldown" using the steam generators) is OPERABLE, 2) the opposite McGuire Units 1 and 2 16.9.15-8 Revision 156

Snubbers 16.9.15 BASES (continued) train of the supported system is OPERABLE, if applicable, and 3) the affected system is logged for tracking in TSAIL. The 72- hour Completion Time is reasonable based on the low probability of a seismic event concurrent with an event that would require operation of the supported system occurring while the seismic snubber(s) are not capable of performing their associated support function, and due to the availability of the redundant train of the supported system (if applicable).

At the end of the specified 72-hour period the required seismic snubbers must be able to perform their associated support function(s}, or the affected supported system LCO(s) shall be declared not met.

Condition A is modified by a Note which specifies that if the opposite train of the associated system becomes inoperable for reasons not related to snubbers while in Condition A, Condition A can be exited and Gondition C is entered.

If the provisions of LCO 3.0.8 are not entered, the supported system shall be declared inoperable immediately.

Remedial Action - B When one or more seismic snubber(s) are not capable of providing their associated support function(s) to more than one train of a multiple train supported system, this commitment allows 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to restore the seismic snubber(s) before declaring the supported system(s) inoperable, provided there is an immediate determination that at least one AFW train (including a minimum set of supporting equipment required for its successful operation) not associated with the non-functional snubber(s), or alternative core cooling method (e.g., feed and bleed, firewater system or "aggressive secondary cooldown" using the steam generators) is OPERABLE. The 12-hour Completion Time is reasonable based on the low probability of a seismic event concurrent with an event that would require operation of the supported system occurring while the seismic snubber(s) are not capable of performing their associated support function.

At the end of the specified 12-hour period the required seismic snubbers must be able to perform their_ associated support fur:iction(s), or the affected supported system(s) LCO(s) shall be declared not met.

If the provisions of LCO 3.0.8 are not entered, the supported system shall be declared inoperable immediately.

Remedial Action - C When one or more seismic snubbers are not capable of providing their associated support function(s) to one train of a multiple train supported system, and the opposite train of the supported system is inoperable for reasons not related to snubbers, this commitment allows up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to restore the seismic snubber(s) before declaring the supported system inoperable provided: 1) there is an immediate determination that at least one AFW train (including a minimum set of supporting equipment required for its successful operation) not associated with the non-functional snubber(s), or alternative core cooling method (e.g., feed and bleed, McGuire Units 1 and 2 16.9.15-9 Revision 156

Snubbers 16.9.15 BASES (continued) firewater system or "aggressive secondary cooldown" using the steam generators) is OPERABLE, and 2) there is an immediate assessment of risk associated with the resulting configuration and the risk assessment is acceptable. The 72-hour Completion Time from failure to meet the COMMITMENT (in case Condition C is entered after exiting Condition A) is reasonable based on the low probability of a seismic event concurrent with an event that would require operation of the supported system occurring while the seismic snubber(s) are not capable of performing their associated support function, and due to an acceptable conclusion of the risk assessment.

At the end of the specified 72-hour period the required seismic snubbers must be able to perform their associated support function(s), or the affected supported system LCO(s) shall be declared not met.

If the provisions of LCO 3.0.8 are not entered, the supported system shall be declared inoperable immediately.

Risk Assessment and Management Remedial Action A, B, and C require that risk be assessed and managed. Industry and NRC guidance on the implementation of 10 CFR 50.65(a)(4) (the Maintenance Rule) does not address seismic risk. However, use of these commitments should be considered with respect to other plant maintenance activities, and integrated into the existing Maintenance Rule Process to the extent possible so that maintenance on any unaffected train or subsystem is properly controlled, and emergent issues are properly addressed. When using this commitment to remove seismic snubber(s) from a functional state, the risk assessment must ensure that at least one AFW train (including a minimum set of supporting equipment required for its successful operation) not associated with the non-functional snubber(s), or alternative core cooling method (e.g., feed and bleed, firewater system or "aggressive secondary cooldown" using the steam generators) is OPERABLE. This risk assessment is tracked by use of the TSAIL program. The risk assessment need not be quantified, but may be a qualitative awareness of the vulnerability of systems and components when one or more snubbers are not able to perform their associated support function. Actions that could be taken include protection of other trains or subsystems for example.

Remedial Action - D If the Required Action and associated Completion Time of Condition A, B or C are not met, the applicable ACTIONS for the train(s) or components(s) associated with the non-functional seismic snubber shall be entered immediately.

Remedial Action - E Should one or more snubbers which have any significant non-seismic loads be non-functional for the purposes of maintenance or testing, OPERABILITY of the affected system(s) and component(s) must be determined and the applicable ACTIONS entered immediately. If there remains a reasonable assurance of OPERABILITY of the affected system(s) or component(s) with the condition of a non-functional snubber(s}, then it is not necessary to enter the respective ACTIONS for inoperable system(s) and component(s).

McGuire Units 1 and 2 16.9.15-10 Revision 156

Snubbers 16.9.15 BASES (continued)

Remediate Action - F Should one or more snubbers (of either category) fail to meet testing acceptance criteria or be discovered in a condition where failure is apparent, an engineering evaluation is to be performed within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, as described in "Functional Test Failure Analysis".

The snubber-testing program may remove snubbers from service and restore OPERABILITY of the snubber application by replacement with another like snubber. In this situation, if the removed snubber application by replacement with another like snubber. In this situation, if the removed snubber later fails to meet test acceptance criteria, Conditions A, B, C, and E are not applicable since the snubber component has no current required function; however, ACTION F.1 would be applicable. During the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed to perform an engineering evaluation, or at any other time when conditions of the affected system(s) and component(s) are determined to no longer support a reasonable assurance of OPERABILITY, applicable ACTIONS shall be entered immediately.

Snubber Testing/Inspection/Service Life Requirements Snubber testing, inspection, and service life requirements using the ASME OM Code, Subsections ISTA and ISTD, are in compliance with 10 CFR 50.55a. These requirements are implemented by administrative procedure AD-EG-MNS-1618 (Reference 14), as described herein.

Visual Inspections Visual Inspections are addressed in the MNS Snubber Program Plan provided in Administrative Procedure AD-EG-MNS-1618.

Refueling Outage Inspections As stipulated in the McGuire Nuclear Station Snubber Program Plan, AD-EG-MNS-1618 (Reference 14), systems which have the potential for a severe dynamic event shall be inspected during each refueling outage to determine whether a severe dynamic event has occurred.

Functional Testing Functional testing is addressed in the MNS Snubber Program Plan provided in Administrative Procedure AD-EG-MNS-1618.

Service Life Monitoring Snubber Service Life Monitoring is addressed in the MNS Snubber Program Plan provided in Administrative Procedure AD-EG-MNS-1618.

McGuire Units 1 and 2 16.9.15-11 Revision 156

Snubbers 16.9.15 REFERENCES

1. Letter from M. S. Tuckman to NRC, Licensing Position Regarding Snubbers, May 20, 1999.
2. Letter from NRC to H.B. Barron, Licensing Position Regarding Snubbers, July 9, 1999.
3. Letter from H.B. Barron to NRC, Request for Relief 97-005, Snubber Inspections -

Performance and Schedule, December 17, 1997.

4. Letter from NRC to H.B. Barron, Relief Request for Snubber Visual examination and Functional Testing, May 27, 1998.
5. Letter from H.B. Barron to NRC, Request for Relief 01-004, June 1, 2001.
6. Letter from NRC to M.S Tuckman, Safety Evaluation of Relief Request No.01-004, Alternative for Snubber Examinations, January 30, 2002.
7. Letter from G.R. Peterson to NRC, Request for Relief 03-002, March 8, 2004.
8. Letter from G.R. Peterson to NRC, RAI Response, September 22, 2004.
9. Letter from NRC to G.R. Peterson, Safety Evaluation of Relief Request No.03-002, November 22, 2004.
10. Technical Specification Task Force (TSTF) 372-A, Revision 4, Addition of LCO 3.0.8.

lnoperability of Snubbers.

11. TSTF-IG-05-03, Rev 1, Technical Specifications Task Force Implementation Guidance for TSTF-372-A, Revision 4, Addition of LCO 3.0.8, lnoperability of Snubbers.
12. Nuclear System Directive 415, Operational Risk Management (Modes 1-3) per 10 CFR 50.65(a)(4).
13. Federal Register, 70FR23252, Notice of Availability of Model Application Concerning Technical Specification Improvement to Modify Requirements Regarding the Addition of Limiting Condition for Operation 3.0.8 on the lnoperability of Snubbers Using the Consolidated Line Item Improvement Process.
14. AD-EG-MNS-1618, McGuire Nuclear Station Snubber Program Plan McGuire Units 1 and 2 16.9.15-12 Revision 156
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