View source for TSTF-03-11, Traveler - November 17, 2003, Transmits TSTF-372, R.3 Addition of LCO 3.0.8, Inoperability of Snubbers

{{Adams
| number = ML033280029
| issue date = 11/17/2003
| title = Traveler - November 17, 2003, Transmits TSTF-372, R.3 Addition of LCO 3.0.8, Inoperability of Snubbers
| author name = Furio P, Infanger P, Silko T, Wideman S
| author affiliation = Technical Specifications Task Force
| addressee name = Beckner W
| addressee affiliation = NRC/NRR/DRIP
| docket = 
| license number = 
| contact person = 
| case reference number = TSTF-03-11, TSTF-372, Rev 3
| document type = Letter type:TSTF
| page count = 40
| project = 
| stage = Other
}}

=Text=
{{#Wiki_filter:TECHNICAL SPECIFICATIONS TASK FORCE TSTF                                              A JOINT OWNERS GROUP ACTIVITY November 17, 2003                                                                       TSTF-03-11 Dr. William D. Beckner, Director Operating Reactor Improvements Program Division of Regulatory Improvement Programs Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

==SUBJECT:==
TSTF-372, Revision 3, Addition of LCO 3.0.8, Inoperability of Snubbers

==Dear Dr. Beckner:==

Enclosed for NRC review is Revision 3 to TSTF-372, Addition of LCO 3.0.8, Inoperability of Snubbers.
As part of a plants conversion to the Improved Standard Technical Specifications (ISTS) or implementation of an amendment prior to conversion, the former TS requirements for snubbers and many other support systems were relocated to a licensee controlled document such as the Technical Requirements Manual (TRM) or a program document. It was intended that when a snubber could not perform the required safety function for a system that is required to be OPERABLE by the TS, the licensee controlled document requirements for the support system would be invoked before the system TS LCO would become applicable. Contrary to this original intention, the NRC has determined that licensees are bound by Technical Specification LCOs 3.0.2 and 3.0.6 which require them to immediately enter the supported system Conditions and Required Actions when a snubber is removed for testing. The only exception is if the supported system has been analyzed and determined to be OPERABLE without the snubber.
Several versions of TSTF-372 have been developed to restore the previous snubber allowance and reviewed by the NRC. A remaining issue of concern is the use of a delay time for those snubbers that affect more than one train or subsystem of a multiple train or subsystem supported system (i.e., LCO 3.0.8.b). At a meeting between the NRC, the TSTF, and the Snubbers Users Group (SNUG) held on June 16, 2003 (see NRC Accession Number ML031710235 for the meeting minutes), the NRC stated that there are several options for evaluating the OPERABILITY of snubbers and their supported systems. These include 1) an engineering analysis of all snubbers; 2) recognize that certain snubbers (e.g., that affect the OPERABILITY of multiple trains) need to be reviewed on a case by case basis, generally by a risk analysis; or 3) performance of snubber maintenance within the time allotted for LCO 3.0.3, generally 7 hours.
11921 Rockville Pike, Suite 100, Rockville, MD 20852 Phone: 301-984-4400, Fax: 301-984-7600 Email: tstf@excelservices.com Administered by EXCEL Services Corporation

TSTF 03-11 November 17, 2003 Page 2 Each of the three options were considered. The TSTF and the SNUG believe that a comprehensive engineering analysis could be performed that would demonstrate that any given snubber unable to perform its support function(s) would not render the supported system inoperable. This belief is based on a large number historical calculations performed to determine the effect of failed snubbers which consistently demonstrated that the supported system was OPERABLE. However, the cost of performing such a plant-by-plant, snubber-by-snubber analysis is prohibitive. Indeed, if such an analysis was performed and the expected results obtained, the need for LCO 3.0.8 would be eliminated as the supported Technical Specification system would always be OPERABLE. Therefore, a more cost-effective solution is desired.
Performing a case-by-case risk analysis of those snubbers that affect the OPERABILITY of multiple trains prior to snubber maintenance or on discovery of a failed snubber is also cost and schedule prohibitive. The use of risk analysis for the effect of seismic events on system OPERABILITY is not well established. Such analyses are time consuming and expensive, providing a strong disincentive to use of such a provision for maintenance. A failed snubber that affects multiple trains would typically require entry into LCO 3.0.3 or a similarly short Completion Time, which does not provide enough time to perform a risk analysis. Furthermore, it is not clear how such a risk analysis would be factored into determining the OPERABILITY of the supported Technical Specification system as the NRCs stated position in Generic Letter 91-18 is that risk cannot be used to determine OPERABILITY.
The Staff also suggested the possibility of intentionally entering LCO 3.0.3 and performing snubber maintenance or repair in the 7 hours allotted before entering MODE 3 under LCO 3.0.3.
Historically, the Staff has discouraged the intentional entry into LCO 3.0.3 for the purpose of preventative maintenance. For example, a letter from J. B. Martin, Region V, to H. R. Denton, NRR, dated March 18, 1987, entitled, Intentional Entry into Technical Specification Limiting Condition for Operation 3.0.3, (Ref. 10) states that occasional entry into LCO 3.0.3 for surveillance or maintenance purposes may be appropriate, however this activity should be well thought-out in advance and strictly controlled by management oversight and appropriate procedures. It also states that intentional entry into LCO 3.0.3 for operational convenience should not be made, except under extremely unusual circumstances where a detailed review by the licensee has concluded that no reduction in safety will result. Because of the NRCs policy licensees have avoided intentional entry into LCO 3.0.3. The TSTF does not recommend promoting a position that intentional entry into LCO 3.0.3 is appropriate for the purpose of snubber testing, maintenance, or repair. However, the TSTF believes that the premise of the NRCs suggestion is valid. After discussions with the SNUG, we believe that a short period of time, in the order of the time frame allowed under LCO 3.0.3, is sufficient to allow necessary testing, maintenance, and repair of those snubbers that affect multiple trains. We are proposing, therefore, that a short period of time be allowed to restore those snubbers that affect multiple trains before declaring the supported system inoperable. We believe that a period of 12 hours is appropriate based on several factors. First, the 7 hour period allowed under LCO 3.0.3 is not a standard Completion Time in the ITS. Second, 12 hours corresponds to the normal length of a shift, simplifying scheduling. Third, standard industry practice is to not schedule maintenance which will take more than one-half the available time. In other words, given a 12 hour available period, work will be scheduled to be completed with 6 hours with the remaining 6 hours

TSTF 03-11 November 17, 2003 Page 3 available to address unexpected events. This is consistent with the 7 hours allowed by LCO 3.0.3.
The TSTF and the SNUG believes that the proposed LCO 3.0.8.b will allow (and encourage) preventative maintenance, testing, and repair to be performed while minimizing plant risk from a seismic event with snubbers not able to perform their safety function(s).
We request that NRC review of TSTF-372 continue to be granted a fee waiver pursuant to the provisions of 10 CFR 170.11. Specifically, the request is to support NRC generic regulatory improvements (risk management technical specifications), in accordance with 10 CFR 170.11(a)(1)(iii). This request is consistent with the NRC letter to A. R. Pietrangelo on this subject dated January 10, 2003.
Should you have any questions, please do not hesitate to contact us.
Steve Wideman (WOG)                                    Tom Silko (BWROG)
Patricia Furio (CEOG)                                  Paul Infanger (BWOG)
Enclosure cc: Drew Holland (NRC)
Biff Bradley (NEI)

TSTF 03-11 November 17, 2003 Page 4 Bcc: Steve Wideman (WOG)
Patricia Furio (CEOG)
Tom Silko (BWROG)
Paul Infanger (BWOG)
Donald Hoffman (EXCEL)
Brian Mann (EXCEL)
Ken Putnam (BWROG)
Ken Vavrek (WOG)

WOG-150, Rev. 0                  TSTF-372, Rev. 3 Technical Specification Task Force Improved Standard Technical Specifications Change Traveler Addition of LCO 3.0.8, Inoperability of Snubbers NUREGs Affected:               1430           1431            1432            1433          1434 Classification: 1) Technical Change                                                Recommended for CLIIP?: Yes Correction or Improvement:            Improvement Industry

==Contact:==
Steve Wideman, (620) 364-4037, stwidem@wcnoc.com See attached justification.
Revision History OG Revision 0                                  Revision Status: Closed Revision Proposed by:        WOG Revision

== Description:==

Original Issue Owners Group Review Information Date Originated by OG: 21-Jul-00 Owners Group Comments:
(No Comments)
Owners Group Resolution:            Approved          Date: 08-Nov-00 TSTF Review Information TSTF Received Date:          08-Nov-00                  Date Distributed for Review: 08-Nov-00 OG Review Completed:              BWOG            WOG            CEOG           BWROG TSTF Comments:
(No Comments)
TSTF Resolution:         Approved                                            Date: 18-Jan-01 NRC Review Information NRC Received Date:           10-Apr-01 Final Resolution:        Superceded by Revision                                     Final Resolution Date:          03-Aug-01 15-Nov-03 Traveler Rev. 3. Copyright (C) 2003, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.

WOG-150, Rev. 0                  TSTF-372, Rev. 3 TSTF Revision 1                                Revision Status: Closed Revision Proposed by:        TSTF Revision

== Description:==

This revision is a complete replacement of Revision 0.
The change has been narrowed in scope to only address snubbers. Other non-Technical Specifications support systems will be addressed in Risk Informed Technical Specifications Task Force (RITSTF) Initiative 7.
TSTF Review Information TSTF Received Date:          13-Dec-01                  Date Distributed for Review: 13-Dec-01 OG Review Completed:              BWOG            WOG            CEOG           BWROG TSTF Comments:
(No Comments)
TSTF Resolution:         Approved                                            Date: 20-Dec-01 NRC Review Information NRC Received Date:           08-Jan-02 NRC Comments:
5/3/2002 - e-mail from NRC: Change requires a safety justification beyond precedent that relied on engineering judgment of "low risk." Staff feels this may best provided by a risk-informed approach that demonstrates congruence with guidance such as RG 1.174 and RG 1.177, using bounding arguments as appropriate to avoid the need for detailed calculations. Staff is formulating feedback to TSTF.
7/19/2002 - Revision prepared.
Final Resolution:        Superceded by Revision TSTF Revision 2                                Revision Status: Closed Revision Proposed by:        TSTF Revision

== Description:==

Based on NRC comments, incorporated risk information to support the change.
Made an editorial change to LCO 3.0.8 to be more consistent with the wording of the other LCO 3.0 Use and Application rules by eliminating multiple instances of the phrase "Technical Specifications." The phrase is not needed as the Section 3.0 LCOs only apply to the Technical Specifications.
Added an additional paragraph to the Bases to describe the use LCO 3.0.8 to circumstances in which a more than one train of a multiple train supported system are affected by snubbers. Revised the Bases to be more consistent with the terminology used in LCO 3.0.8 and the other 3.0 Bases.
TSTF Review Information TSTF Received Date:          19-Jul-02                  Date Distributed for Review: 19-Jul-02 OG Review Completed:              BWOG            WOG            CEOG           BWROG 15-Nov-03 Traveler Rev. 3. Copyright (C) 2003, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.

WOG-150, Rev. 0                  TSTF-372, Rev. 3 TSTF Revision 2                                Revision Status: Closed TSTF Comments:
(No Comments)
TSTF Resolution:         Approved                                            Date: 31-Jul-02 NRC Review Information NRC Received Date:           13-Aug-02 NRC Comments:                                                                       Date of NRC Letter:           13-Dec-02 From 12/31/2002 Letter:
We are sensitive to the need for appropriate completion times for repair or planned maintenance of certain snubbers that affect more than one train. For example, the discovery of a failed snubber should not place the plant in a shutdown sequence. However, the proposed wording of the LCO 3.0.8 is too broad. Further, our experience in working with the TSTF to develop the generic bounding seismic risk analysis for one-train impact leads us to believe that licensees in general may not be capable of performing a meaningful seismic risk assessment. Since the current 50.65(a)(4) industry guidance does not address seismic risk, we cannot rely on the 50.65(a)(4) process to adequately address the inoperability of snubbers that affect more than one train.
We have modified the proposed LCO to address snubbers that affect single and multiple trains. We expect that licensees will adopt the generic one-train allowance, and submit plant-specific analysis for any multiple train configurations they want to justify. If a detailed plant-specific seismic risk analysis is not available, an acceptable assumption for a simple bounding analysis is to assume loss of offsite power and the loss of all affected trains and systems.
Draft TSTF-372 Revision 2 LCO 3.0.8 wording also addressed seismic restraints and supports. We have concluded that LCO 3.0.8 should not contain seismic restraints or supports other than snubbers. The staff has determined that adequate guidance exists in NRC Bulletins 79-02, Revisions 0, 1, and 2, and Supplement 1 to Revision 1; 79-14, Revisions 0 and 1, and Supplements 1 and 2 to Revision 1; and Generic Letter 91-18, Revision 1 dated October 8, 1997. This precedence is documented in a letter dated February 20, 1992 to Northeast Nuclear Energy Company. The TSTF can evaluate this precedent and justify the need for a change, if appropriate.
Final Resolution:        Superceded by Revision                                     Final Resolution Date:          13-Dec-02 TSTF Revision 3                                Revision Status: Active Revision Proposed by:        TSTF Revision

== Description:==

Previous discussion drafts of TSTF-372 had two options. One or more inoperable snubbers that were associated with a single train were provided with a 72 hour delay time before declaring the supported system inoperable.
However if a snubber was associated with more than one train, only a single such snubber can be inoperable to use the 72 hour delay time. The NRC accepted the delay time regarding snubbers that affect a single train, but they did not accept the provision for snubbers that affect multiple trains and asked for extensive plant-specific justification for applying a delay time for each snubber.
At a meeting between the TSTF, the Snubbers Users Group (SNUG), and the NRC on June 16, the NRC and the Industry discussed several options for moving ahead on TSTF-372. Following that discussion the SNUG discussed the issue at a meeting of their group. Based on the feedback from both meetings, a new revision was developed.
15-Nov-03 Traveler Rev. 3. Copyright (C) 2003, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.

WOG-150, Rev. 0                  TSTF-372, Rev. 3 TSTF Revision 3                                Revision Status: Active This revision of TSTF-372 retains the original provisions and justification for inoperable snubbers that affect a single train and the 72 hour delay time. For inoperable snubbers that affect more than one train a 12 hour delay time is proposed.
TSTF Review Information TSTF Received Date:          03-Oct-03                  Date Distributed for Review: 03-Oct-03 OG Review Completed:              BWOG            WOG            CEOG           BWROG TSTF Comments:
(No Comments)
TSTF Resolution:         Approved                                            Date: 08-Nov-03 NRC Review Information NRC Received Date:           10-Nov-03 Affected Technical Specifications LCO 3.0                     LCO and SR Applicability LCO 3.0.2                   LCO and SR Applicability LCO 3.0.8                   LCO and SR Applicability Change

== Description:==
Adds LCO 3.0.8 LCO 3.0.8 Bases             LCO and SR Applicability Change

== Description:==
Adds LCO 3.0.8 15-Nov-03 Traveler Rev. 3. Copyright (C) 2003, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.

TSTF-372, Rev. 3

==1.0 DESCRIPTION==

The proposed change would add a new LCO 3.0.8 to Section 3.0, LCO and SR Applicability, of the improved Standard Technical Specifications (ISTS) to allow a delay time for snubbers which cannot perform their required support function, before the supported systems are declared inoperable.

==2.0 PROPOSED CHANGE==

The proposed change will add a new LCO to Section 3.0, LCO and SR Applicability, of the ISTS. This new LCO, LCO 3.0.8, states:
When one or more required snubbers are unable to perform their associated support function(s), any affected supported LCO(s) are not required to be declared not met solely for this reason if risk is assessed and managed, and:
: a. the snubbers not able to perform their associated support function(s) are associated with only one train or subsystem of a multiple train or subsystem supported system or are associated with a single train or subsystem supported system and are able to perform their associated support function within 72 hours; or
: b. the snubbers not able to perform their associated support function(s) are associated with more than one train or subsystem of a multiple train or subsystem supported system and are able to perform their associated support function within 12 hours.
At the end of the specified period the required snubbers must be able to perform their associated support function(s), or the affected supported system LCO(s) shall be declared not met.
Bases describing the new LCO 3.0.8 are also added.

==3.0 BACKGROUND==

Component standard supports are those metal supports which are designed to transmit loads from the pressure-retaining boundary of the component to the building structure. Although classified as component standard supports, snubbers require special consideration due to their unique function. Snubbers are designed to provide no transmission of force during normal plant operations, but function as a rigid support when subjected to dynamic transient loadings.
Therefore, snubbers are chosen in lieu of rigid supports where restricting thermal growth during normal operation would induce excessive stresses in the piping nozzles or other equipment.
The location and size of the snubbers are determined by stress analysis. Depending on the design classification of the particular piping, different combinations of load conditions are established. These conditions combine loading during normal operation, seismic loading and loading due to plant accidents and transients to four different loading sets. These loading sets Page 1

TSTF-372, Rev. 3 are designated as: normal, upset, emergency, and faulted condition. The actual loading included in each of the four conditions depends on the design classification of the piping. The calculated stresses in the piping and other equipment for each of the four conditions must be in conformance with established design limits. Supports for pressure-retaining components are designed in accordance with the rules of the ASME Boiler and Pressure Vessel Code, Section III, Division 1 (Ref. 1). The combination of loadings for each support, including the appropriate stress levels, meet the criteria of Regulatory Guide 1.124, Design Limits and Loading Combinations for Class 1 Linear-Type Component Supports (Ref. 2), and Regulatory Guide 1.130, Design Limits and Loading Combinations for Class 1 Plate-and -Shell-Type Component Supports (Ref. 3).
As part of a plants conversion to the Improved Standard Technical Specifications (ISTS) or implementation of an amendment prior to conversion, the former TS requirements for snubbers and many other support systems were relocated to a licensee controlled document such as the Technical Requirements Manual (TRM) or a program document. The conversion submittal or split report amendment application identified the snubbers as a candidate for relocation based on the fact that the TS requirements did not meet any of the four criteria in 10 CFR 50.36(c)(2)(ii) for inclusion in the ITS. The removal of these requirements from the TS was classified as a relocation as opposed to a more restrictive or less restrictive change, and the NRC approved the relocation without placing any restriction on the use of the relocated requirements. Therefore it was intended that when a snubber could not perform the required safety function for a system that is required to be OPERABLE by the TS, the licensee controlled document requirements for the support system would be invoked before the system TS LCO would become applicable. For example, if a snubber was determined to not meet the licensee controlled documents requirements, it needed to be either restored or replaced with a known working snubber within 72 hours, and an engineering evaluation would also need to be performed for the attached component within that same 72 hour period. If these actions are not completed within the allocated time, the system supported by the snubber would be declared inoperable and the Conditions and Required Actions for that system followed.
Contrary to this original intention, the NRC has taken the position that licensees are bound by Technical Specification LCOs 3.0.2 and 3.0.6 which require them to immediately enter the supported system Conditions and Required Actions when a snubber is removed for testing. In other words, once the snubber LCO is removed from the Technical Specifications, there is no exception from the Technical Specification requirements for snubbers and if a snubber is removed for maintenance, testing, or repair, the supported system Conditions and Required Actions must be entered immediately. The only exception is if the supported system has been analyzed and determined to be OPERABLE without the snubber.
In a July 9, 1999 letter from the NRC to Duke Power (Ref. 4) the NRC presented the above position. It was stated that if a licensee has implemented the Improved Standard Technical Specifications and relocated the Snubber specification from the Technical Specifications, the 72 hour snubber Required Action and Completion Time in the TRM could not be utilized prior to entering the supported system TS Condition and Required Actions. At the Winter 2000 Snubber Users Group (SNUG) meeting, Dr. Arnold Lee of the NRC reiterated that position.
At a June 13-14, 2000, TSTF/NRC meeting, Dr. Bill Beckner, Chief of the NRC Technical Specifications Branch, indicated that there was sufficient precedent to support a position that the 72 hour Completion Time can be considered a delay time. The NRC Technical Specification Branch has stated that not having the 72 hour window to perform testing is an unintended burden that resulted from implementing the Improved Technical Specifications. An example of Page 2

TSTF-372, Rev. 3 this precedence is in the NRC memorandum dated May 27, 1986, Technical Specification Interpretation on Snubbers, which specifically stated that, It should be recognized that the snubber TS are unique in that the operability requirements do not require consideration of associated system redundancy or impact until a snubber is out of service in excess of 72 hours.
At that meeting, the NRC indicated that their preference for a resolution to the issue was some type of change to the Section 3.0 requirements. The intent of this proposed change is to preserve this precedent.

==4.0 TECHNICAL ANALYSIS==

The purpose of this change is to provide the same level of operational safety and flexibility provided by the snubbers as was provided prior to conversion to ITS or plant specific relocation of the snubber TS requirements. Prior to conversion to the ITS or plant specific relocation of snubber requirements, snubbers were located in the TS. If one or more snubbers were inoperable, the TS action statements for snubbers were taken. Under the pre-ITS conventions and rules, the supported system was not considered inoperable while the snubber action statements were being taken. Only when the snubber action times were expired (or if directed by the snubber action statements) was the supported system considered inoperable and its the supported system TS action statements followed . This interpretation of the snubber TSs is based on the May 27, 1986 NRC memorandum (Ref. 5) which states, in part:
Normally snubbers would only be removed from a system for testing/surveillance purposes at a time when the system is not required to be operable. If, however, a snubber is removed from service, for any purpose, for a system which is required to be operable, the action statement for snubbers would apply. The action statement requires that inoperable snubber(s), those removed for testing, be restored to operable service in 72 hours.
The action statement also requires that an engineering evaluation of the attached component be performed in accordance with specification 4.7.9.g or that the attached system be declared inoperable. This specification (4.7.9.g) notes that where snubbers are found inoperable, an engineering evaluation is to determine if the components to which inoperable snubbers are attached were adversely affected to assure that the component remains capable of meeting its designated service. The intent of this requirement is to assure that the system was not adversely affected by the inoperable snubber. This does not relate to the system or components capability to withstand a seismic event. Any degradation in seismic protection due to inoperable snubbers was taken into account in establishing the 72 hour allowed outage time.
When a snubber is removed from service for testing, an engineering evaluation need not be performed. If the snubber is not returned to service in 72 hours, that system would be declared inoperable at this time since the snubber allowable out-of-service time limit would be exceeded.
Snubbers did not meet the 10 CFR 50.36(c)(2)(ii) criteria for retention in the TS and during ITS conversion or a plant specific relocation amendment were relocated to a licensee controlled document, such as a Technical Requirements Manual (TRM) or a program document. This relocation did not alter the requirements on the snubbers, but allowed those requirements to be changed under the auspices of 10 CFR 50.59. An unintended consequence of that relocation is to require, under ITS LCO 3.0.2, the supported systems remaining in TS to be immediately Page 3

TSTF-372, Rev. 3 declared inoperable and their Conditions and Required Actions taken when one or more snubbers is not capable of performing its required safety function.
This change in operation is not justified by any decrease in plant safety related to the relocation of the snubber requirements but is strictly an administrative consequence of the relocation. The plant design has not changed. The operational actions taken when one or more snubbers does not meet its requirements did not change as a consequence of the relocation. The snubbers continue to perform the function assumed in the safety analysis and the same actions continue to be taken if those snubbers cannot perform that function. However, under the ITS, the supported system must be declared inoperable and its Conditions and Required Actions followed, even to the point of a plant shutdown, even though there has been no change in the design or operation of the plant. This decreases plant safety and operational flexibility.
In addition, the position presented in the July 9, 1999 letter has had a substantial effect on snubber maintenance, testing, and repair across the industry. Where possible, snubber maintenance, testing, and repair is performed when the supported system is inoperable, such as during system maintenance windows or during refueling outages. However, these maintenance windows are crowded, so snubber inspection and maintenance must be kept to a minimum. The net effect of the position is to reduce the snubber testing to the minimum required by the relocated snubber requirements. This effect is not beneficial for the industry or the NRC.
The proposed LCO 3.0.8 corrects this unintended consequence and restores the level of plant safety afforded by the snubbers prior to their relocation.
The plant safety analyses assume that the required safety systems are OPERABLE, except for a single failure. When relying on Conditions and Required Actions, a single failure is not assumed. The purpose of TS Completion Times is to minimize the length of time that equipment can be out of service in order to minimize the probability that an accident could occur while equipment is unavailable. As a result, this change has no effect on the safety analyses.
The inoperability of TS supported systems will continue to be limited by the delay time associated with the snubbers and other seismic restraints and the Conditions and Required Actions of the supported system. These delay times were considered to be consistent with the safety analysis assumptions prior to relocation from the subject TS to the TRM and continue to be consistent with the safety analysis.
LCO 3.0.8.a The analysis provided below considers snubbers not able to perform their associated support function(s) associated with only one train or subsystem of a multiple train or subsystem supported system or associated with a single train or subsystem supported system (i.e., LCO 3.0.8.a). At some plants, there is a limited population of snubbers which, by design, support more than one train or subsystem of a multiple train or subsystem supported system. LCO 3.0.8.b addresses these snubbers.
Pipe and equipment supports, in general, are not directly considered in developing the accident sequences for theoretical hazard evaluations. Further, some Probabilistic Risk Assessment (PRA) studies have indicated that snubbers are not of prime importance in a risk significant sequence (Ref. 6 and 7) and the function of snubbers is not essential in mitigating the consequences of a DBA or transient (Refs. 8 and 9). However, such studies may not be Page 4

TSTF-372, Rev. 3 applicable to all U.S. plants. Therefore, a simplified risk assessment is provided to justify the proposed 72 hour delay time in LCO 3.0.8.a.
The initiating event of concern is loss of offsite power (LOOP). Ceramic insulators used in power distribution systems have a high confidence (95%) of low probability (5%) of failure (HCLPF) at an earthquake level of 0.09g, expressed in terms of peak ground acceleration.
Thus, a 0.1g earthquake would be expected to have a 5% probability of causing a LOOP initiating event, resulting in a plant trip, starting and loading of emergency AC generators, and functioning of safety systems necessary to shut down the reactor and maintain it in a safe condition. This level of earthquake is assumed to fail the piping system for which the snubber(s) is out of service. This is a conservative bounding assumption for the assumed 0.1g earthquake.
Piping systems are very rugged and the actual failure probability would be a function of the stress allowables and the number of snubbers removed for maintenance. Plants are designed such that failure of one train or subsystem should not impact the functionality of the remaining train or subsystem. There would be a small conditional probability of seismic failure of the remaining train (due to very large earthquakes), but this number is considered negligible for this analysis.
Earthquake frequencies in different parts of the US vary widely, however, as a very general approximation, the following is assumed: Using the EPRI seismic hazard curves, the frequency of a 0.1g earthquake is approximately 1E-3/yr for an Eastern US plant, and approximately 1E-1/yr for a West Coast US plant.
For the limiting (West Coast) plant:
1E-1/yr earthquake frequency X 5E-2 failure probability for insulators = 5E-3/yr frequency for earthquake induced LOOP.
Given the earthquake induced LOOP, one train of mitigation will remain available. (Non earthquake LOOP initiators would continue to have two trains of mitigation available.) A single train of safety grade equipment can be generally assumed to have a reliability of 98%. Thus, the probability of non-mitigation is 2%, or 2E-2.
Thus, for the West Coast plant, the change in Core Damage Frequency (CDF) would be 5E-3/yr X 2 E-2, or 1E-4/yr. For a 72 hour period, the incremental core damage probability (ICDP) would be 1E-4 X 72/8760 = 8 E-7.
For an Eastern US plant, the delta CDF would be 1E-6/yr, and the ICDP for a 72 hour period would be 8E-9.
NRC Regulatory Guide 1.182, guidance for implementation of 10 CFR 50.65(a)(4), endorses NUMARC 93-01. Section 11 of NUMARC 93-01 provides the following table of ICDP values and risk management actions:
Page 5

TSTF-372, Rev. 3 ICDP and ILERP, for a specific planned configuration, may be considered as follows with respect to establishing risk management actions:
ICDP                                                                          ILERP
  > 10-5         configuration should not normally be entered voluntarily        > 10-6 10 10-5    assess non quantifiable factors & establish risk                10 10-6 management actions
  < 10-6         normal work controls                                            < 10-7 As can be seen, the ICDP for the limiting West Coast plant is within the normal work controls region. Therefore, the risk contribution from snubber removal is within the normal range of maintenance activities carried out at the plant. Risk management actions may be considered for the West Coast plant, as the value approaches the 1E-6 ICDP threshold for establishment of risk management actions. Also, if LCO 3.0.8 is frequently used at a West Coast plant, its use should be tracked such that the annual CDF is not increased by more than a minimal amount over the plants baseline value.
For most plants in the Eastern US, the ICDP value is so small that tracking should not generally be necessary. Some Eastern plants may have higher local earthquake frequencies, and could conservatively be treated similar to the West Coast plants.
LCO 3.0.8.b Several versions of TSTF-372 have been developed to restore the previous snubber allowance and reviewed by the NRC. A remaining issue of concern is the use of a delay time for those snubbers that affect more than one train or subsystem of a multiple train or subsystem supported system (i.e., LCO 3.0.8.b).
At a meeting between the NRC, the TSTF, and the SNUG held on June 16, 2003 (see NRC Accession Number ML031710235 for the meeting minutes) the NRC stated that there are several options for evaluating the OPERABILITY of snubbers and their supported systems.
These include 1) an engineering analysis of all snubbers; 2) performance of snubber maintenance within the time allotted for LCO 3.0.3, generally 7 hours; or 3) recognize that certain snubbers (e.g., that affect the OPERABILITY of multiple trains) need to be reviewed on a case by case basis, generally by a risk analysis.
Each of the three options are discussed below. The TSTF and the SNUG believe that a comprehensive engineering analysis could be performed that would demonstrate that any given snubber unable to perform its support function(s) would not render the supported system inoperable. This belief is based on a large number historical calculations performed to determine the effect of failed snubbers which consistently demonstrated that the supported system was OPERABLE. However, the cost of performing such a plant-by-plant, snubber-by-snubber analysis is prohibitive. Indeed, if such an analysis was performed and the expected results obtained, the need for LCO 3.0.8 would be eliminated as the Technical Specification system would always be OPERABLE. Therefore, a more cost-effective solution is desired.
Performing a case-by-case risk analysis of those snubbers that affect the OPERABILITY of multiple trains prior to snubber maintenance or on discovery of a failed snubber is also cost and schedule prohibitive. The use of risk analysis for the effect of seismic events on system OPERABILITY is not well established. Such analyses are time consuming and expensive, Page 6

TSTF-372, Rev. 3 providing a strong disincentive to use of such a provision for maintenance. A failed snubber that affects multiple trains would typically require entry into LCO 3.0.3 or a similarly short Completion Time, which does not provide enough time to perform a risk analysis. Furthermore, it is not clear how such a risk analysis would be factored into determining the OPERABILITY of the supported Technical Specification system as the NRCs stated position in Generic Letter 91-18 is that risk cannot be used to determine OPERABILITY.
The Staff also suggested the possibility of intentionally entering LCO 3.0.3 and performing snubber maintenance or repair in the 7 hours allotted before entering MODE 3 under LCO 3.0.3.
Historically, the Staff has discouraged the intentional entry into LCO 3.0.3 for the purpose of preventative maintenance. For example, a letter from J. B. Martin, Region V, to H. R. Denton, NRR, dated March 18, 1987, entitled, Intentional Entry into Technical Specification Limiting Condition for Operation 3.0.3, (Ref. 10) states that occasional entry into LCO 3.0.3 for surveillance or maintenance purposes may be appropriate, however this activity should be well thought-out in advance and strictly controlled by management oversight and appropriate procedures. It also states that intentional entry into LCO 3.0.3 for operational convenience should not be made, except under extremely unusual circumstances where a detailed review by the licensee has concluded that no reduction in safety will result. Because of the NRCs policy licensees have avoided intentional entry into LCO 3.0.3. We do not recommend promoting a position that intentional entry into LCO 3.0.3 is appropriate for the purpose of snubber testing, maintenance, or repair.
However, the TSTF believes that the premise of the NRCs suggestion at the June 16 meeting is valid. After discussions with the SNUG, we believe that a short period of time, in the order of the time frame allowed under LCO 3.0.3, is sufficient to allow necessary testing, maintenance, and repair of those snubbers that affect multiple trains. We are proposing, therefore, that a short period of time be allowed to restore those snubbers that affect multiple trains before declaring the supported system inoperable. We believe that a period of 12 hours is appropriate based on several factors. First, the 7 hour period allowed under LCO 3.0.3 is not a standard Completion Time in the ITS. Second, 12 hours corresponds to the normal length of a shift, simplifying scheduling. Third, standard industry practice is to not schedule maintenance which will take more than one-half the available time. In other words, given a 12 hour available period, work will be scheduled to be completed with 6 hours with the remaining 6 hours available to address unexpected events.
The TSTF and the SNUG believes that the proposed LCO 3.0.8.b will allow (and encourage) preventative maintenance, testing, and repair to be performed while minimizing plant risk from a seismic event with snubbers not able to perform their safety function(s).
Despite the fact that the industry (a)(4) guidance, NUMARC 93-01, does not currently address seismic risk, the use of LCO 3.0.8 should be considered with respect to other plant maintenance activities, and integrated into the existing 10 CFR 50.65(a)(4) process. This is necessary to ensure that maintenance on the remaining train is properly controlled, and emergent issues are properly addressed.
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TSTF-372, Rev. 3 5.0 Regulatory Analysis 5.1 No Significant Hazards Consideration The TSTF has evaluated whether or not a significant hazards consideration is involved with the proposed generic change by focusing on the three standards set forth in 10 CFR 50.92, Issuance of amendment, as discussed below:
: 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No.
The proposed change allows a delay time before declaring supported TS systems inoperable when the associated snubber(s) cannot perform its required safety function.
Entrance into Actions or delaying entrance into Actions is not an initiator of any accident previously evaluated. Consequently, the probability of an accident previously evaluated is not significantly increased. The consequences of an accident while relying on the delay time allowed before declaring a TS supported system inoperable and taking its Conditions and Required Actions are no different than the consequences of an accident under the same plant conditions while relying on the existing TS supported system Conditions and Required Actions. Therefore, the consequences of an accident previously evaluated are not significantly increased by this change. Therefore, this change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
: 2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No.
The proposed change allows a delay time before declaring supported TS systems inoperable when the associated snubber(s) cannot perform its required safety function. The proposed change does not involve a physical alteration of the plant (no new or different type of equipment will be installed) or a change in the methods governing normal plant operation.
Thus, this change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
: 3. Does the proposed change involve a significant reduction in a margin of safety?
Response: No.
The proposed change allows a delay time before declaring supported TS systems inoperable when the associated snubber(s) cannot perform its required safety function. The proposed change restores an allowance in the pre-ISTS conversion TS that was unintentionally eliminated by the conversion. The pre-ISTS TS were considered to provide an adequate margin of safety for plant operation, as does the post-ISTS conversion TS.
Therefore, this change does not involve a significant reduction in a margin of safety.
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TSTF-372, Rev. 3 Based on the above, the TSTF concludes that the proposed change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.
5.2 Applicable Regulatory Requirements/Criteria This change does not alter compliance with any applicable regulatory requirements or criteria, but provides a delay time before declaring supported TS systems inoperable when the associated snubber(s) or other seismic restraint(s) cannot perform its required function. This delay time, similar to a Completion Time in the TS, does not alter the design or licensing basis of any system.
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 Commissions regulations, and (3) the approval of the proposed change will not be inimical to the common defense and security or to the health and safety of the public.

==6.0 ENVIRONMENTAL CONSIDERATION==

A review has determined that the proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent 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 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

==7.0 REFERENCES==
: 1. ASME Boiler and Pressure Vessel Code, Section III.
: 2. Regulatory Guide 1.124, Design Limits and Loading Combinations for Class 1 Linear-Type Component Supports, Revision 1, January 1978.
: 3. Regulatory Guide 1.130, Design Limits and Loading Combinations for Class 1 Plate-and Shell-Type Component Supports, Revision 1, October 1978.
: 4. Letter dated July 9, 1999, from F. Rinaldi, NRC to H. Barron, Duke Energy Corporation, McGuire Nuclear Station, Units 1 and 2 RE: Licensing Position Regarding Snubbers (TAC NOS. MA5519 and MA5520).
: 5. NRC Memorandum dated May 27, 1986, from H. Denton to C. Norelius, Technical Specification Interpretation on Snubbers.
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TSTF-372, Rev. 3
: 6. Zion Probabilistic Safety Study, Commonwealth Edison Company, September 1981.
: 7. Millstone Unit 3 Probabilistic Safety Study, North-East Utilities Company, August 1983.
: 8. NRC Staff Review of Nuclear Steam Supply System Vendor Owners Groups Application of the Commissions Interim Policy Statement Criteria to Standard Technical Specifications. Attachment to letter dated May 1988 from T. E. Murley, NRC to W. Wilgus, Chairman the B&W Owners Group.
: 9. WCAP-11618, MERITS Program-Phase II, Task 5, Criteria Application, including Addendum 1 dated April, 1989, Section 3.7.9.
: 10. NRC Memorandum dated March 18, 1987, from J. B. Martin to H. R. Denton, Intentional Entry into Technical Specification Limiting Condition for Operation 3.0.3.
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TSTF-372, Rev. 3 INSERT 1 LCO 3.0.8 When one or more required snubbers are unable to perform their associated support function(s), any affected supported LCO(s) are not required to be declared not met solely for this reason if risk is assessed and managed, and:
: a. the snubbers not able to perform their associated support function(s) are associated with only one train or subsystem of a multiple train or subsystem supported system or are associated with a single train or subsystem supported system and are able to perform their associated support function within 72 hours; or
: b. the snubbers not able to perform their associated support function(s) are associated with more than one train or subsystem of a multiple train or subsystem supported system and are able to perform their associated support function within 12 hours.
At the end of the specified period the required snubbers must be able to perform their associated support function(s), or the affected supported system LCO(s) shall be declared not met.
INSERT 2 LCO 3.0.8 LCO 3.0.8 establishes that systems are considered to remain capable of performing their intended safety function when the only issue associated with the system is that 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 snubbers not capable of performing their associated support function(s). This is appropriate because a limited length of time is allowed for maintenance, testing, or repair of one or more snubbers not capable of performing their associated support function(s) and appropriate compensatory measures are specified in the snubber requirements, which are located outside of the Technical Specifications (TS) under licensee control. The snubber requirements do not meet the criteria in 10 CFR 50.36(c)(2)(ii), and, as such, are appropriate for control by the licensee.
If the allowed time expires and the snubber(s) are unable to perform their associated support function(s), the affected supported systems LCO(s) must be declared not met and the Conditions and Required Actions entered in accordance with LCO 3.0.2.
LCO 3.0.8.a applies when one or more snubbers are not capable of providing their associated support function(s) to a single train or subsystem of a multiple train or subsystem supported system or to a single train or subsystem supported system. LCO 3.0.8.a allows 72 hours to restore the snubber(s) before declaring the supported system inoperable. The 72 hour Completion Time is reasonable based on the low probability of a seismic event concurrent with an accident or transient that would require operation of the supported system occurring while the snubber(s) are not capable of performing their associated support function and due to the availability of the redundant train of the supported system.
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TSTF-372, Rev. 3 LCO 3.0.8.b applies when one or more snubbers are not capable of providing their associated support function(s) to more than one train or subsystem of a multiple train or subsystem supported system. LCO 3.0.8.b allows 12 hours to restore the snubber(s) before declaring the supported system inoperable. The 12 hour Completion Time is reasonable based on the low probability of a seismic event concurrent with an accident or transient that would require operation of the supported system occurring while the snubber(s) are not capable of performing their associated support function.
LCO 3.0.8 requires 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 LCO 3.0.8 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. The risk assessment need not be quantified, but a qualitative awareness of the vulnerability of systems and components when one or more snubbers are not able to perform their associated support function.
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