ML20081J590
| ML20081J590 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 03/20/1995 |
| From: | Mcmeekin T DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9503280050 | |
| Download: ML20081J590 (13) | |
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DukeIbw Company T.C MdfEHN AlcGuire Nudear Genemtion Department kice President 12700Hagen ferryRoad(MG0lVP)
(7M)87M800 Huntencille,NC28078M5 (704)87M809 Fax DUKEPOWER March 20, 1995 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
McGuire Nuclear Station Docket Nos:
50-369 and 370 Relief Request 94-012: Snubber Inspection Intervals for Revision 1 Unit 2
Dear Sir:
Pursuant to 10 CFR
- 50. 55a (g) (5) (iii),
I am submitting the attached relief request for NRC review and approval.
Per NRC Generic Letter 90-09 dated December 11, 1990 on
' Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions':
...the staff has developed an alternate schedule for visual inspections that maintains the same confidence level as the existing schedule and generally will allow the licensee to perform visual inspections and corrective actions during plant outages.
Because this line item TS improvement will reduce future occupational radiation exposure and is highly cost effective, the alternate inspection schedule is consistent with the Commission's policy statement on TS improvements.
The attached relief request seeks relief from impractical snubber inspection frequencies and will invoke the snubber testing frequency as reflected in the current McGuire Nuclear Station Technical Specifications 3.7.8, Table 4.7-2 which are the same as those reflected in the referenced GL 90-09.
Should there be any questions regarding this matter, please contact James E.
Snyder at (704) 875-4447.
Very truly yours, vYv T. C. McMeekin 280031 l0 f 9503280050 950320 9
PDR ADOCK 05000369 0
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U.S. Nuclear Regulatory Commission March 20, 1995 Page 2/3 xc:
Mr.
S.
D. Ebneter Administrator, Region II U.S. Nuclear Regulatory Commission 101 Marietta St.,
NW, Suite 2900 Atlanta, Ga.
30323 Mr. Victor Nerses U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Mail Stop 14H25 Washington, D.C.
20555 Mr. Robert E. Martin U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C.
20555 k
Mr. George F. Maxwell NRC Resident Inspector McGuire Nuclear Station Dayne Brown, Chief Division of Radiation Protection P.
O. Box 27687
- Raleigh, N. C.
27611-7687 J
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' March 20, 1995 U.S. Nuclear Regulatory Commission Page 3/3 bxc:
Jesse O. Barbour (EC07J)
Jerry Goodman (EC07J)
G. A. Copp (EC050)
Z. L. Taylor (CN01RC)
E. Burchfield (ON01RC)
W.
R. Cross Kay L. Crane Dwin E.
Caldwell 4
P.
T. Vu John M. Washam 4
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DUKE POWER COMPANY MCGUIRE NUCLEAR STATION Request for Relief From ASME Code Section XI Requirements I.
' Component for Which Relief is Requested A. Name and Identification Number All Unit 2 safety-related snubbers.
B.
Function Snubbers are designed to prevent pipe motion under 5
dynamic loads.
C. ASME Section XI Code Class Provides support for Class 1,2,3 systems.
D. Valve Category Not applicable.
II.
ASME Code Section Requirement that has been determined to be impractical.
ASME Boiler and Pressure Vessel Code Section XI, Article IWF-5000.
III.
Basis for Requesting Relief The 1989 ASME Boiler and Pressure Vessel Code Section XI, Article IWF-5300 (a) states: " Inservice examinations shall be performed in accordance with the first Addenda to ASME/ ANSI OM-1987, Part 4 (published 1988), using theil visual examination method described in IWA-2213." Parage aph 2.3.2.2 of the first Addenda to ASME/ ANSI OM-1987, Part 4 states that examinations shall be conducted at 18 month intervals +25%.
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'If unacceptable snubber's are revealed, the interval for 5
subsequent inspections shall be reduced in accordance with:
thelfollowing table:
L 4
Number of' Unacceptable Months to Subsequent
. Snubbers-Examination O'
18.
1 12 2
6-3,4 4
5,7 2
>8 1
McGuire Unit 2 Technical Specifications 3/4.7.8, SNUBBERS has a surveillance frequency not to exceed 48 months which is altered based on the number of unacceptable snubbers-found during the-previous inspection in prcportion t3 the siLes of the various snubber populations or categories.
See the attached copy of the:
subject TS Table 4.7-2, SNUBBER VISUAL INSPECTION' INTERVAL.
The examination interval requirements in the McGuire Unit 2 TS Table 4.7-2 are based on NRC Generic Letter 90-09, ' Alternative Requirements for Snubber Visual Inspection Intervals and' Corrective Actions.'
Prior to the incorporation of-GL 90-09 into the TS, the examination inspection interval in:the TS was identical to that in the first Addenda to ASME/ ANSI-OM-1987, Part.
4.
NRC GL 90-09 acknowledged that licensees having a large number of snubbers find that the 18 month visual inspection schedule in the first' addenda to ASME/ ANSI _OM-1987, part 4 is excessively restrictive and that some licensees have spent a significant amount of resources and have subjected plant personnel to unnecessary radiological exposure to comply with the, visual examination requirements without increasing-the confidence level in. snubber operability.
McGuire Unit 2 has 359 snubbers subject to the inservice inspection per IWF-5000. McGuire Unit 2 is currently on a fuel cycle length of approximately 18 months.
In order to comply with the current ASME requirements of IWF-5000, Duke' Power would be required to perform VT-3, visual examinations on all 359 snubbers within the~ inservice inspection program at every refueling outage.
This examination frequency is twice that presently required by the approved TS 3/4.7.8 and significantly greater than ' hat required under Section XI codes through the 1986 edition.
As indicated in NRC GL 90-09, this increased inspection per ASME requirements does not increase the confidence level in.
snubber operability above that obtained by the requirements of NRC GL 90-09.
IV.
Alternate Testing As an alternative to the requirements of ASME Section XI, IWF-5000, paragraph IWF-5300(a) which invokes the inspection frequency in paragraph 2.3.2.2 of the first Addenda to ASME/ ANSI OM-1987, Part 4 (published in 1988), VT-3, visual inspection of snubbers within the Section XI inservice inspection boundaries shall be examined on a schedule as provided by McGuire Nuclear Station TS 3/4.7.8, Table 4.7-2.
For the purposes of determining inspection frequency, the snubbers within the inservice boundaries shall be considered part of the total population of snubbers inspected under TS 3/4.7.8.
6
f PLANT SYSTEMS 3/4.7.8 SNUBBERS LIMITING CONDITION FOR OPERATION 3.7.8 All snubbers shall be OPERABLE.
The only snubbers excluded from the requirements are those installed on non-safety-related systems and then only if the failure or the failure of the system on which they are installed would not have an adverse effect on any safety-related system.
APPLICABILITY:
MODES 1, 2, 3, and 4.
MODES 5 and 6 for snubbers located on systems required OPERABLE in those MODES.
ACTION:
With one or more snubbers inoperable, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> replace or restore the inoperable snubber (s) to OPERABLE status and perform an engineering evaluation per Specification 4.7.8g. on the attached component or declare the attached system inoperable and follow the appropriate ACTION statement for that system.
SURVEILLANCE REQUIREMENTS 4.7.8 Each snubber shall be demonstrated OPERABLE by performance of the following augmented inservice inspection program and the requirements of Specificati n 4.0.5.
a.
Inspection Types As used in this specification, type of snubber shall mean snubbers of the same design and manufacturer, irrespective of capacity.
b.
Visual Inspections Snubbers are categorized as inaccessible or accessible during reactor operation and may be treated independently.
Each of these categories (inaccessibleandaccessible)maybeinspectedindependentlyaccord-ing to the schedule determine by Table 4.7-2.
The visual inspection interval for each category of snubber shall be determined based upon the criteria provided in Table 4.7-2 and the first inspection inter-val determined using this criteria shall be based upon the previous inspection interval as established by the requirements in effect before Amendment Nos. 126 and 108.
McGUIRE - UNITS 1 and 2 3/4 7-18 Amendm. nt No.126 (Unit 1)
Amendment No.108 (Unit 2)
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l Table 4.7-2 SNUBBER VISUAL INSPECTION INTERVAL NUMBER OF UNACCEPTABLE SNUBBERS Population Column A Column B Column C i
or Category Extended Interval Repeat Interval-Reduce Interval (Notes 1 and 2)
(Notes 3 and 6)
(Notes 4 and 6)
(Notes 5 and 6) 1 0
0 1
80 0
0 2
100 0
1 4
150 0
3
,8 200 2
5 13 300 5
12 25 400 8
18 36 500 12 24 48 750 20 40 78 1000 or greater 29 56 109 Note 1:
The next visual inspection interval for a snubber population or category size shall be determined based upon the previous inspection interval and the number of unacceptable snubbers found during that f
interval.
Snubbers may be categorized, based upon their accessi-bility during power operation, as accessible or inaccessible.
The g
j categories may be examined separately or jointly. However, the i'
licensee must make and document that decision before any inspection i
and shall use that decision as the basis upon which to determine the next inspection interval for that category.
Note 2:
Interpolation between population or category size and the number of unacceptable snubbers is permissible.
Use next lower integer for the 'value of the limit for Columns A, B, or C if that integer includes a fractional value of unacceptable snubbers as described by interpolation.
Note 3:
If the number of unacceptable snubbers is equal to or less than the number in Column A, the next inspection interval may be twice the previous interval but not greater than 48 months.
McGUIRE - UNITS I and 2 3/4 7-18a Amendment No.126 (Unit 1)
Amendment No.108 (Unit 2)
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E Table 4.7-2 (continued)
SNUBBER VISUAL INSPECTION INTERVAL Note 4:
If the number of-unacceptable snubbers is equal to or less than the-Column B but greater than the number in Column A, the next inspection shall be the same as the previous interval.
Note 5:
If the number of unacceptable snubbers is equal to or greater than
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the number in Column C, the next inspection interval shall be.two-t thirds of the previous interval. However, if the number of unaccep-table snubbers is less than the number in Column C but greater than
.i the number in Column B, the next interval shall be reduced propor-
.tlonally by interpolation, that is, the previous interval shall be
" educed by a factor that is one third of the ratio of the difference Detween the number of unacceptable snubbers found during the previous interval and the number in Column B to the difference in the numbers in Columns B and C.
Note 6:
The provisions of' Specification 4.0.2 are applicable for all inspection intervals up to and including 48 months.
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a McGUIRE - UNITS 1 and 2 3/4 7-18b Amendment No.126 (Unit 1)
Amendment No.108 (Unit 2) 4
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SbRVEILLANCEREQUIREMENTS(Continued) c.
Refueling Outage Inspections At each refueling, the systems which have the potential for a severe dynamic event, specifically, the main steam system (upstream of the i
main steam isolation valves) the main steam safety and power-operated relief valves and piping, auxiliary feedwater system, main steam supply to the auxiliary feedwater pump turbine, and the letdown and charging portion of the CVCS system shall be inspected to determine if there has been a severe dynamic event.
In case of a severe dynamic event, mechanical snubbers in that system which experienced the event shall be ins)ected during the refueling outage to assure that the mechanical snu)bers have freedom of movement and are not frozen up.
The inspection shall consist of verifying freedom of motion using one of the following:
(1) manually induced snubber movement; (2) evaluation of in place snubber piston setting; (3) stroking the mechanical snubber through its full range of travel.' If one or more mechanical snubbers are found to be frozen up during this inspection, those snubbers shall be replaced or repaired before returning to power.
The requirements of Specification 4.7.8b. are independendent of the requirements of this specification.
d.
Visual Inspection Acceptance Criteria Visual inspections shall verify:
(1) that there are no visible indications of damage or impaired OPERABILITY, and (2) attachments to the foundation or supporting structure are secure.
Snubbers which aonear inoperable as a result of visual inspections "shall be classi?Ted as unacceptable and may be reclassified acceptable" for thi purpose of establishing the next visual inspection interval, provid.d that:
(1) the cause of the rejection is clearly established and remedied for that particular snubber and for other snubbers irrespective of type that may be generically susceptible; McGUIRE - UNITS 1 and 2 3/4 7-19 Amendment No.126(Unit 1)
Amendment No.108(Unit 2) n
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EPLANT SYSTEMS.
SURVEILLANCE REQUIREMENTS (Continued) d.
Visual Inspection Acceptance Criteria (Continued).
and (2) the affected snubber is functionally tested in the as found condition and determined OPERABLE per Specification 4.7.8f.
A hy-draulic snubber found with the fluid port uncovered and'all hydraulic snubbers found connected to an inoperable common reservoir shall be classified as unacceptable and may be reclassified acceptable by functionally testing each snubber starting with the piston in the' as-found setting, extending the piston rod in the tension direction.
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Functional Tests i
During the first refueling shutdown and at least once per refuel'ing thereafter, a representative sample of snubbers shall be tested using one of the following sample plans. The large bore steam generator hydraulic snubbers shall be treated as a separate population for func-tional test pur>oses.
A 10% random sample from previously untested snubbers shall )e' tested at least once per refueling outage until the entire population has been tested.
This testing cycle shall then.
begin anew.
For each large bore steam generator hydraulic snubber that does not meet the' functional test acceptance criteria, at least i
10% of the remaining population of untested snubbers for that testin,g cycle shall be tested. -The sample plan shall be' selected prior to the test period and cannot be changed during the test period. The NRC shall be notified of the sample plan selected prior to the: test 1
period.
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At least 10%.of the snubbers required by Specification 3.7.8.
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. shall be functionally tested either in place or in a bench test.
E For each snubber that does-not meet the functional test acceptance i
criteria of Specification 4.7.8f., an additional-10% of the snubbers shall be functionally tested until no more failures are found i
or until all snubbers have been functionally tasted; or
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2)
A representative sample of the snubbers required by Specifica-tion 3.7.8 shall be functionally tested in accordance with' Figure 4.7-1.
"C" is the total number of snubbers found not meeting the acceptance requirements of Specification 4.7.8f (failures).
The cumulative number of snubbers tested is denoted by "N."
Test results shall be plotted sequentially in the order l
of sample assignment (i.e., each snubber shall be plotted by 1
its order in the random samale assignments, not by the order of l
testing).
If at-any time tie point plotted falls in the " Accept".
f
- region, testing of snubbers may be terminated. When the point-plotted lies in the " Continue Testing"in the. region additional snubbers 3
shall be i.ested until the point falls Accept" region, or f
all the snobbers required by Specification 3.7.8 have been tested.
Testing equipment failure during functional testing may invalidate that day s testing and allow that day's testing to resume anew at a later time, providing all snubbers tested with the failed equipment during the day of equipment failure are retested; or L.
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.McGUIRE - UNITS 1 and 2-3/4 7-20 Amendment No.126(Unit 1).
Amendment No.108(Unit 2) i i
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n PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) e.
Functional-Tests (Continued)
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An initial representative sample of fifty-five (55) snubbers shall be functionally tested.
For each snubber which does not meet the functional test acceptance criteria, another sample of at least one-half the. size of the initial sample shall be tested until the total numbe'r tested is equal to the initial sample size multiplied by the factor,1 + C/2, where "C" is the number of snubbers found which do not meet the functional test acceptance criteria.
This can be plotted using an " Accept" line which follows j
the equation N = 55(1 + C/2).
Each snubber should be plotted as soon as it is tested.
If the point plotted falls on or below the " Accept" line, testing may be discontinued.
If the point plotted falls above the " Accept" line, testing must continue unless all snubbers have been tested.
The representative samples for the functional test sample plans e
shall be randomly selected from the snubbers required by Specifi-cation 3.7.8 and reviewed before beginning the testing. The review n
shall ensure as far as practical that they are representative of the various configurations, operating environments, range of sizes, and capacities.
Snubbers placed in the same locations as snubbers which failed the previous functional test shall be retested at the time of the next functional test but shall not be included in the sample plan.
If during the functional testing, additional sampling is required due to failure of only one type of snuboer, the functional testing results shall be reviewed at that time to determine if additional samples should be limited to the type of snubber which has failed the functional testing, f.
Functional Test Acceptance Criteria The snubber functional test shall verify that:
1)
Activation (restraining action) is achieved within the specified range in both tension and compression, except that inertia dependent, acceleration limiting mechanical snuboers may be tested to verify only. that activation takes place in 4
both directions of travel; j
2)
Snubber bleed, or release rate where required, is present in i
both tension and compression, within the specified range; i
3)
Where required, the force required to initiate or maintain motion of the snubber is within the specified range in both 1
direction of travel; ane
~4)
For snubbers specifically required not to displace under continuous load, the ability of the snubber to withstand load without displacoment.
Testing methods may be used to measure paramet0rs indirectly or parameters other than those specified if those nsults can be correlated to the specified parameters through established methods.
l McGUIRE - UNITS 1 and 2 3/4 7-21 Amendment No. 99 (Unit 1)
Amendment No. 31 (Unit 2)
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PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued)-
g.
Functional Test Failure Analysis An engir'eering evaluation shall'be made of.each failure to meet the-
- functional test acceptance criteria to determine the cause of the failure.
The results of this evaluation shall be used, if applicable, in selecting snubbers to.be tested in an effort.to z determine the OPERABILITY.of other ' snubbers irrespective of type which may be subject to the same failure mode.
For the snubbers found. inoperable, an engineering evaluation shall; be performed on the components to-which the: inoperable snubbers are attached.
The purpose of this engineering evaluation shall be to~
determine if the components to which the inoperable snubbers are attached were adversely affected by the inoperability of the' snubbers in order to ensure that the component remains capable of meeting the designed service.
If any snubber selected for functional testing either fails to.
activate or fails to move, i.e., frozen-in place, the cause will be evaluated and,-if caused by manufacturer or design deficiency, all snubbers of the same type subject to the same defect shall be'evafuated in a manner t6 ensure their OPERA 8ILITY.
This testing' requirement shall be independent of the requirements stated in Specification 4.7.8e.
for' snubbers' not meeting the functional test acceptance criteria, h.
Functional Testing of Repaired and Replaced Snubbers Snubbers-which fail the visual inspection or the functional test acceptance criteria shall be repaired'or replaced.
Replacement' snubbers and snubbers which have' repairs which might affect the functional test result shall be tested to meet the functional test criteria before installation-in the unit.. Mechanical snubbers'shall have met the acceptance criteria subsequent to their most recent.
service, and freedom-of-motion test must have been performed within 12 months before being installed.in the unit.
i.
Snubber Seal Replacement Program The seal service life of hydraulic snubbers shall.be monitored to ensure that the' service life is not exceeded between surveillance inspections.
The expected service. life for the various seals, seal materials, and applications shall'be determined and established based on engineering information and the' seals shall be replaced so.
that the expected service life will not be exceeded during a period-when the snubber is required to be OPERABLE.
The' seal replacements shall be documented and the docucentation shall be retained'in accordance with Specification'6.10.2.
McGUIRE - UNITS 1 and 2 3/4'7-22 Amendment No. 86(Unit l) l Amendment No. 67(Unit 2) -
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