ML20087D995
| ML20087D995 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 01/10/1992 |
| From: | NORTHERN STATES POWER CO. |
| To: | |
| Shared Package | |
| ML20087D987 | List: |
| References | |
| NUDOCS 9201170232 | |
| Download: ML20087D995 (16) | |
Text
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Exhibit B Prairlo Island Nuclear Generating Plant License Amendment Request Dated January 10, 1992 I Proposed Changes Marked Up !
On Existing Technical Specification Pages Exhibit B consists of existing and new Technical Specification pages with the !
proposed changes highlighted on those pages. The existing pages affected by 1 this License Amendment Request are listed below:
r TS xii TS.4.13 1 T5.4.13 2 TS.4.13 3 B.4.13 1 .
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TS xil IECIUllCAL SPECir1 CAT 10NS Ll$1,DF TABLES TS TABLE I1111 3.5 1 Engineered Safety Features Initiation Instrurtent Limiting Set Points J 3.5 2 Instrument Operating Conditions for Psactor Trip j 3.5 3 Instrunent operating conditions for Emergency Cooling System 3.5 4 Instrument Operating Conditions for Isolation Functions 3.5 5 Instrument Operating Conditions for Ventilation Systerns 3.5 6 Instrurnent Operating Conditions for Auxiliary Electrical System 3.9 1 Radioactive Liquid Effluent Monitoring Instrumentation 3.9 2 Radioactive Gaseous Effluent Honitoring instrurnentation 3.14 1 Safety Related Fire Detection Instruments 3,15 1 Event Monitoring instrumentation Process 6 Containment 3.15 2 Event Monituring instrumentation Radiation 4.11 Hinitran Frequencies for Checks, Calibrations and Test of Instrument Channels 4.1 2A Minimum Frequencies for Equipment Tests 4,1 2B Mintinum Frequencies for Sarapling Tests 4.2 1 Spectel Inservice Inspection Requirements 441 Unit 1 and Unit 2 Penetration Designation for Leakago Tests 4.10 1 Radiation Environmental Monitoring Program (REMP)
Sample Collection and Analysis 4.10 2 RIEp . Maximum Values for the Lower Litaits of Detection 4.10 3 RTMP Reporting Levels for Radioactivity Concentrations in Environmental Samples 4.12 1 Steam Generator Tube Inspection 4113i1Q.;iyS nubbeGi sus 19thipe c tibidlnt e rval
! 4.17 1 Radioactive Liquid Effluent Monitoring Instrumentation L _
Surveillance Requirernents
! -4.17 2 Radioactive caseous Effluent Monitoring instrumentation Surveillance Requirements 4.17 3 Radioactive Liquid Waste Sampling and Analysis Program 4.17-4 Radioactive Caseous Waste Sampling and Analysis Program 5.5 1 Anticipated Annual Release of Radioactive Material in-1.iquid Effluents Froin Prairie Island Nuclear Generating i Plant (Per Unit) 5.5 2 Anticipated Annual Reles1e of Radioactive Nuclides in l
Gaseous Effluent Froin Prairie Island Nuclear Generating Plant (Per Unit) 6.1 1 Mintinuta Shift Crew Composition
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4.13 SNUI)!'l:RS 6Dpilcab.111tv I
Applica to periodic testing and surveillance requirements of safety related hydraulic snubbers.
9.h3 tI111C To verify the 4n4+gr44y-een! OpERABII,1TY of hydraulic anubbers. !
Specification The following surveillance requiremente apply to all safety related snubbers. These requirements augment the inspections required by Section XI of the ASME Code.
A. V6*o.64-4nepect4+n-of-nem14.cre-+ha!! 'r m .h eoed-in-e+eerdane4.-* A44i tho-fellow k g-*ehedu k +
No,--ef--GnwWora4*umi Hmit-14mtv4rmt 40*teveble-t*ce instu.e&4+n-per4*d Iwyftt-kn-Peried O 4 8-monthe-444 4 44-w.ndie 444 0 6-**nt 4,e44h h4 444-days-444 bb4 63-dayo-44%
S m =cre 44-dayo44h he-owtul+*4-4**Pe*44*"-4etww 1-oh*14 et ' - 4+ngthened-were 44.a t. = = c t+p - : - 64 m As';used ini thierspecificition/l* type of s,nubber";c shall> mear[ snubbers of _thefnamt design;andftnanufacturer,;irrespectived capacity.j Snubbers may-4.e ars categorized in-veo-groupew as " accessible" or
" inaccessible" based on their accessibility for inspection during reactor operation. Weer- = greepe $act[of;there categories
{UiaccessibleJandll accessible) may be inspected independently .
according to the ebeve schedule dsterminedjbf} Table' TSj4.13E1?
Th4 visual Pinepsettorifintsrvd1? for" each Ltype of unubber "sliall;bu determined. based upon the criteria providedjin Table.TS.4 1)fi.f B. Visual inspections shall verify that (1) tha&-4here-er+ the" snubber hai no visible indications of damage or impaired OPERAByl.!TY. (2) attachments to the foundationTor supporting structure are ecou++
fdiicti6na1l, and ( 3) 4*-44,***-l***&ie**-wher+-++mbhor--eevemen6-oen-4+
l mam**14y-l+ wha +ed-wl44awat-dkeenneet4ng-4 he-mmbbee r-4,b*4,--44.*-anubboe l hao4reedom-of-*evemen&-end-le-not,4r+sen~*p fastenFrs ? fori the attachsent" of the snubberito.f the?tonpolientlan,d. to(thaf snubber anchoragejkreif unctional. Snubbers which appear inoperable as a result of v1sual inspectionsTsha11[befc14ssified[atunacceptabidiand inajibeftselusi._fibd[atseptlable may-be-<ter**ke<t4 t w*bk for the purpose of establishing-the next visual inspection intervalg by+
provided lthatjf
l TS.4.13 2 !
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- a. Clwer4y-ee4+h14ehf ; 3 cause of the rejection is clearly l established and rated for that particular snubber and for othero snubbers. irrespective' 6f L type that inay be generically susceptible; and t
- b. Funet4*na14y-tce44ng The af fected snubber is ' functionally tested in the as found ondition and f4nding-4+ determined OpfJtAB12 per Specification 4.D.D.
Heweve rAen he-f4 u ld-pe r4-e f-*-byd rau l4 c-e nuhhe r-l e-fwa s--4 +-bo uneeverwir-44 e-enubber-eha14-ho-+enn4 der 4 44neper+hlo-f+r-purpene::
ef-+e4+h14+hing-44te-ne*4-v4*wal-inspect 4+*-4*4 orvalv All hydraulic snubbers (c.nd connected to an inoperable common hydraulic fluid ,
reservoir shall be considerwl-en-4*eperable-enubbe++ counted'as unacceptable' f or> determining thii next' inspection' interval . A review .
and evaluation shall be performed and' documented'to ' justify continued operation with an ut iacceptable snubber. ..If continued operation cannot;be justified, the snubber 'shall be. declared inoperable.and thei applicable action statement requirements shan bo met.
C. Except as specified below, functional testing of snubbers shall be conducted at least once per 18 monthm7 dur4ng-eeld-ehutdower Ten percent of the total of each type snubber shall be functionally tested either in place or in a bench test. For each snubber that does not meet the functional test acceptance criteria in Specification 4.13.D below, an additional ten percent of that type of snubber shall be functionally tested until no reore failures are found or all snubbers of that typo have been tested.
L The representative sample r, elected for functional testing shall incim'e the various configurations, operating environments, and the range of size and capacity of the snubbers. Twenty five percent of the sample shall include snubbers from the following three categories.
- Yh., first snubber away from a reactor vessel nozr.le
- h. & utters within five feet of heavy equipment (valve, pump, irhine, motor, etc.)
- c. Snubbers within ten feet of the discharge of a safety / relief valve Snubbers identified as " High Radiation Area" or " Difficult to Remove" are exernpt from functional testing provided a justifiabic basis for exernption is presented for Comrnission review; snubber life testing is perfortned to qualify snubber operability for all design conditions; or snubbers of the same type, configuration, and similar service hav9 been tested for a ten year period and no failures have occurred. In such
! exernpt cases, a qualitative test report shall be on file to substitute for the required functional testing.
In addition to the regular sarnple and specified re sampling, snubbers which failed the previous funct?onal test shall be retested during the next test period. If a spare snubber has been installed in place of a failed snubber, then both the f ailed snubber, if it is repaired and
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installed in another position, and the spare snubber shall be retested.
TS.4.13 3 4rt%,C. - Cork, if any snu'eb.s selected fct functional testing either fails to lockup or faite to move (i.e.. frozen in place) the c wee shall be evaluated and all snubbers subject to the same defect shall be functionally tested. This testing is in addition to the regular sample and specified re. samples.
D. Ilydraulic snubber functionni testo shall v>rify thati
- a. Activation (restraining action) to achieved within the specified rango ci velocity or acceleration in both teu Jon -
and compression.
- t. Snubber biced, or release rate, where required, is within
. the specified range in compression or tension. For snubbers specifically required to not displace under continuous load, the ability of the snubber to witbetand load without displace-ment shall be verified. j E. -An engineering evaluation shall be performed for all components !
supported by inoperable snubbers. The purpose of. this engineering '
evaluation shall be to determine if the components were adversely affected by the inoperable snubber (s) to ensure that the components 4 remain capable of meeting the designed service. -
F. The installation and maintenance records for each snubber shall be reviewed at least once every 18_ months to verify that the indicated service life will not be exceeded prior to the next scheduled >
snubber service life review. If the indicated service life will be f exceeded, the snubber service life sball be reevaluated or the1 anubber shall be replaced or reconditioned to extead its servico life beyond the date of the next scheduled servico life review. J This re evaluation, replaceae..t. or reconditioning shall be '
indicated in the records.
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TAllLE TS.4.13 +1 l Page 1 of 2 l TABLE TU.4.13 1 SEQDEll VISUA(, INSPECTION INT GVAL hmber of Unaeceotghlp,,,,,$nghhtIs .
Popul'a tion Column A Column b Col m n C or Category . Extend' Interval- Ropeat Interval- Reduce: Interval (Notes 1 and 2)- INotid 3 and 6) (Notes 4 and 61- (Notes 5 and 61 1- 0 0 1 )
80 0 0 2 I
100~ 0.. -1l 4 150- 0 -3' 8 i 200 2 5 13 i 300f _
12 25 ;
400 _8 18 36 500 -12 24~ 48 7$0! 20 40 78 1000 Tor.grpater -29 56' 109 Noto if The next visualLinspection interval'~for a anubber population' or category size shall-be. determined basedSipon the previous inspection interval Sud the tuimber of unacceptable snubbers found'duritig that interval; 1
Snubbers may be categorized,' based upon their--accessibility during power operation, as at.cessibic or inaccessible.- These categories may be examined-~separr,tely.or jointly : However. : that decision must be made and documented _before any inspection and that decision. shall' be used as the -
basis ~upon;which to determine.the next inspection. interval for that category.
Note 2: !1nteirpolationLbetween population or category atzes and theinumber of unacceptable snubbero is permissible. Use'next lower integer for.the value'of the limit for Columns A B or C:if that integer includen a fractional valuelof unacceptable snubbers.as determined by interpol.ation!
NoteJ3: If' theinumber ~of unacceptable snubbers in- equal toior lean' than L thn
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number"In Column A, the next . inspection interval may be twice _ the previous interval but :)ot greater than 48. months,
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Note 4:l If; the number of unacceptablo' snubbers 'i's aquel Jto or 1csa than' the number in" Column B' but greater than theLnu.aber in Column A, the next inspection intervalfahall be the'saec as'the-previous interval.
l TABLE TS';4.13y1 Page.2 Lot 2 Note: S G I ff thes ;-;'nusbe rl*of' ~unacceptabis hndbbers : is ;equall to ' c e : greater" than ;tlin number;.in Column C Jthe next inspection: interval ~shall be two thirds of -
the previous f.uterval.L 11ovover. -:!f the;numaer- of:Lunacceptable_onubbers in.less thhh'the! number.in columnl0 but"greaterLthan<the number:in ColurnnlB;-ithafnext;1intervalishall be: reduced proportionally by interpolation kthatiis;_.the~ previous interval shall be reduced by'a factor that~is tne-third of"the ratio.of-the^ difference between the viumber of unacskptablels' hub'uors ; f ound ;durind the previousLinterval:- and the ;numbirrfin; Column; B Joithuidif ferance;. in; theinumbora iriColumns B. and V
NoteJ6t > A11'inspbetion intervals' np"fr.o' and(incipding;::s48 ; months" mayf be'. adjusted -.a saxpumoflplusforminus;25%!
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B.4.13 1 4.13 SGBAFl$
DMia The visual inspection frequency is based upon maintaining a constant level of snubber protection to systems. Therefore, the required inspection interval varies inversely with the observed snubber failures and is determined by the number of inoperable snubbers found during an inspection. Inspectiens performed before that intervs1 has elapsed may be used as a new reference poirt to determine the next inspection. However, the results of such early inspections performed bafore the original required time interval hes elapsed (nominal time less 25%) may not be used to lengthen the required inspection interval. Any inspection whose results require a shorter inspection interval will override the previous schedule.
When the cause of the rejection of a snubber is clearly established and remedied for that snubber and for any other snubbers that may be
. generically susceptible, and vot ified by inservice functional testing, that snubber may be exempted from being counted as inoperable.
Generically susceptible snubbers are those which are of a specific make or model and have the same design features directly related to rejection of the snubber by visual inspection, or are similarly 1;cated or exposed to the same environmental conditions such as temperature, radiation, and vibration, When a snubber is found inoperable, an engineerin6 evaluation is performed, in addition to the determination of the snubber mode of failuro, in order to determine if any safety-related component or system has been adversely affected by the inoperability of ti.e snubber. The engineering evaluation chall determine whether or not the snubber mode of failure has imparted a significant effect or degradation on the supported component or system.
To provide assurance of snubber functional reliability, a representative sample of 10% of the installed snubbers will be functionally tested daring plc.n t '"*inte at 18 month intervals. ' Observed failures of these sample 1?nubbers shall require functional testing of additional units.
The service life of a snubber is evaluated via manufacturer input and information through consideration of the snubber service conditions and associated installation and maintenance-records (newly installed snubber, ceal replaced, spring replaced, in high radiation area, in high
,g temperature area, ote...). The requirement to monitor the snubber service J life is included to ensure that the snubbers periodically under80 a performance nvaluation in view of their age .nd operating > conditions .
Theso records wil' provide statistical bases for future consideration of snubber service ILfe.
All. safety-related snubbers installed or planned for use at Prairie Island are hydraulic anubbers. No mechanical snubbers are used.
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73 Exhibit C Prairie Island Nuclear Generating Plant License Amendment Request Dated January 10, 1992 Revised-Technical Specification Pages Exhibit C consists of revised and new pages for the Prairie Island Nuclear Generating Plant Technical Specification with the proposed changes _
incorporated. The revised and new pages are listed below:
TS-xii TS.4.13 1 TS.4.13-2 TS.4.13 3 TABLE TS.4.13-1 (Page 1 of 2)
TABLE TS.4.13-1 (Page 2 of 2)
B.4.13-1 M
_ _ _ _ _ _ _ _ ____-__um ma-_ mmm--A
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, TS nii TECHNICAL SPECIFICATIONS I LIST OF TABLES TS TABLE 11115 3.5 1 Engineered Safety Features Initiation Instrument Limiting Set Points 3~5 2
. Instru'nent Operatini, Conditions for Reactor Trip 3.5 3 Instrument Operating Conditions for Emergency Cooling System
~3.5-4 Instrument Operating Conditions for Isolation Functions 3.5-5 Instrument operating conditions for Ventilation Systems 3.5-6 Instrument Operating Conditions for Auxiliary Electrica'. System ;
l 3.9 1 _ Radioactive Liquid Effluent Monitoring Instrumentation l 3.9 2 ' Radioactive Caseous Effluent Monitoring instrumentation i 3,14-1 Safety Related Fire Detection Instruments 3.15 1 Event Monitoring-instrumentation Process & Containment 3,15-2 Event Monitoring instrumentation Radiation !
4.1-1 Minimum Frequencies for Checks, Calibrations and Test of Instrument Channels ;
.4.1-2A- Minimum Frequencies for Equipment Tests 4.1 2B Minimum Frequencies for Sampling Tests j 4 .2 1- Special Inservice-Inspection Requirements 4.4 1 Unit 1 and Unit 2 Penetration Designation for Leakage Tests 4.10-1 Radiation Environmental Monitoring Program (REMP)
Sample Collection and Analysis 4,10-2 RFMP - Maximum Values-for the Lower Limits of Detection 4.10-3 RFMP Reporting Levels for Radioactivity Concentrations in Environmental Samples
.4.12 1 Steam Cencrator Tube Inspection 3 4,'13-1 Snubber' Visual Inspection Interval ~
'4.17 Radioactive Liquid Effluent Monitoring Instrumentation y' '
Surveillance Requirements 4,17-2' ' Radioactive Gaseous Effluent Monitoring instrumentation Surveillance Requirements 4.17-3 Radioactive' Liquid Waste Sampling and Analysis Program 4.17 4 Radioactive Gaseous Waste Sampling and Analysis Program: I 5.5-1. ' Anticipated Annual Release of Radioactive Material in-Liquid Effluents From-Prairie _ Island Nuclear _ Generating Plant-(Per Unit) 5.5-2 Anticipated Annual Release of Radioactive Nuclides in Gaseous-Effluent From-Prairie Island Nuclear Generating Plant (Per Unit) 6.1-1 Minimum Shift Crew Composition
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TS.4.13 1 ,
4.13 SNUBBERS.
Applicability Applies to periodic testing and surveillance requirements of safety related hydraulic snubbers.
Qhitstive To verify the OPERABILITY of hydraulic snubbers, Specification 1he following surveillance requirements apply to all safety related snubbers, These requirements augment the inspections required by Section X1 of the ASME Code, A. As 'used in this specification, " type of snubber" shall mean snubbers of the same' design and manufacturer, irrespective of capacity.
Snubbers are categorized as " accessible" or " inaccessible" based on their accessibility for inspection during reactor operation. Each of these categories (inaccessible and accessible) may be inspected independently according to tha schedule determined by Table TS.4.13 1.
The; visual inspection interval for each type of snubber shall be determined based upon the criteria provided in Table TS.4.13 1, B. LVisual inspections shall verify that (1) the snubber has no visible indications of damage or impaired OPERABILITY, (2) attachments to the '
foundation or supporting structure are functional, and (3) fasteners for the attachment of the' snubber to the component and to the snubber anchorage are functional. Snubbers which appear inoperable as a result of visual inspections shall-be classified as unacceptable and
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may be reclassified acceptable foi the purpose of establishing the next: visual inspection interval, provided that:
- a. The cause of the rejection is clearly established and remedied for that particular snubber and for other-snubbars irrespective of type that may be generically susceptible; and b, The affected snubber is functionally tested in the as-found condition and determined OPERABLE per Specification 4.13.D.
All _ hydraulic snubbers found connected to an inoperable common hydraulic fluid' reservoir shall be counted as unacceptable for determining the next inspection interval. A review and evaluation shall be performed and documented to justify continued operation with an unacceptable snubber, if continued operation cannot be justified, the snubber shall-be declared inoperable and the appilcable action
. statement requirements.shall be met.
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-TS.4.13 2 C. Except as specified below, functional testing of snubbers shall be conducted at least once per 18 months. Ten percent of the total of each type snubber shall be functionally tested either in place or in a bench
-test, For each snubber that does not meet the functional test acceptance criteria in Specification 4.13.D below, an additional ten percent of that type of snubber shall be functionally tested until no more failures are found or all snubbers of that type have been tested.
The representative sample selected for functional testing shal. include the various configurations, operating environments, and the range of
. size and capacity of the snubbers. Twenty five percent of the sample shall include snubbers from the following three categories.
- a. The first snubber away from a reactor vessel nozzle
- b. Snubbers within five feet of heavy equipment (valve, pump, i turbine, motor, etc.) l l
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- c. Snubbers within ten feet of the discharge of a safety / relief valve Snubbers identified as "High Radiation Area" or " Difficult to Remove" i are exempt from functional testing provided a justifiable basis for exemption is presented for Commission review; anubber life testing is performed to qualify snubber operability for all design conditions; or snubbers of the same type, configuration, and similar service have been tested for a ten year-period and no failures have occurred. In such exempt cases, a qualitative test report shall be on file to substitute for the required functional testing.
In addition'to the regular sample and specified re-sampling, snubbers which failed the previous functional test shall be retested during the next test period. If a spare snubber has been installed in place of a failed snubber, then both the failed snubber, if it is repaired and installed in another position, and the spare snubber shall be retested.
If _any snubber selected for functional testing either fails to._ lockup or falls to move (i.e., frozen in place) the cause shall be evaluated and all snubbers subject to the same defect shall be functionally tested, This testing is in addition to
=the regular = sample and specified re-samples.
D. Ilydraulic snubber func.tional tests shall verify that;
- a. Activation (restraining action) is achieved within the specified range'of velocity or acceleration in both tension and compression.
(: b. Snubber _ bleed 'or release rate, where required, is within the specified' range in compression or tension. For snubbers specifically required to not displace under continuous load,
. the ability of the snubber to withstand load without displace-mer.t shall be verified.
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TS 4.13 3
.s E. An engineering evaluation _shall be_ performed for all components supported by inoperable snubbers, The purpose of this engineering evaluation shall belto_ determine if_the components were adversely affected by the Inoparable snubber (s) to ensure that the components remain capable of meeting the designed service.
F, The installation and maintenance records for each snubber shall be
- reviewed at least once every 18 months to verify that the indicated j service life will not be exceeded prior to the next scheduled ]
snubber service life rev'ew. If the indicated service life will be ;
-exceeded, the snubber service life shall-be reevaluated or the -l snubber _ shall be replaced or reconditioned to extend its service !
life beyond the date of the next scheduled service life review.
This_re evaluation,1 replacement, or reconditioning shall be indicated in the records.
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TABLE TS.4.13-1 Page 1 of 2 TABLE TS.4.13 1 SNUBBER VISUAL INSPECTION INTERVAL Number of Unacceptable Snubbers Population Column A Column B Column C or Category Extend Interval Repeat Interval Reduce Interval (Notes 1 and 2) ,[Hotes 3 and 6) (Notes 4 and 6) (Notes 5 and 6) 5 1 0 0 1 80 0 0 2 100 0 1 4 130 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- sual 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 interval.
Snubbers may be categorized, based upon their accessibility during power operation, as accessible or inaccessible. These categories may be:
examined separately or jointly. However, that decision must be made and documented before any inspection and that decision shall be used as the basis upon which to determine the next inspection interval for that category.
Note 2: Interpolation between population or category sizes 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-determined 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.
Note 4: If the number of unacceptable snubbers is equal to or less than the number in Column B but greater tnan the number in Column A, the next inspection interval shall be the same as the previous interval.
- . .4 TABLE TS.4.13 1 Page 2 of 2 Note 5:- If the number of unacceptable snubbers is equal to or greater than the number in Column C, the next inspection interval shall ba two thirds of the ' previous interval . Ilowever, if the number of unacceptable snubbers is less than the number in Column C but greater than the number in Column B, the next interval shall be reduced proportionally by interpolation, that is the previous interval shall be reduced by a f ac'.or that is one third of the ratio of the difference between the
'. amber 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: All inspection intervals up to and including 48 months may.be adjusted a maximum of-plus or minus 25%.
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, B.4.13 1 4.13 SNUBBERS Baseg '
The visual inspection frequency is based upon maintaining a constant level of snubber protection to systems. Therefore, the required inspection interval varies inversely with the observed snubber failures and is determined by the number of inoperable snubbers found during an inspection. -Inspections performed before that interval has elapsed may be used as a new reference point to determine the next inspection. Ilowever, the results of such early inspections performed before the original required time interval has elapsed (nominal time less 256) may not be used to lengthen the required inspection interval. Any inspoetion whose >
results require a shorter inspection interval will override the previous schedule; When the cause of the rejection of a snubber is clearly established and remedied for that snubber and for any other snubbers that may be generically susceptible, and verified by inservice functional testing, that snubber may be exempted from being counted as inoperable.
Generically susceptible snubbers are'those Which are of a specific make or model and have the same design features directly related to rejection of the snubber by visual inspection, or are similarly located or exposed to the same environmental conditions such as temperature, radiation, and vibration.
When a snubber is found inoperable, an engineering evaluation is performed, in addition to the determination of the snubber mode of failure, in order to determine if any safety related component or system has been adversely affected by the inoperability of the snubber. The engineering cvaluation shall determine whether er not the snubber mode of failure has imparted a significant effect or degradation on the supported component or system.
To provide . assurance of snubber functional reliability, a representative sample of 10%- of the installed snubbers will be functionally tested at 18 month intervals. Observed failures of these sample. snubbers shall require functional testing of additional units.
The service life of a snubber is evaluated via manufacturer input and information through consideration of the snubber service conditions and associated-installation and maintenance records (newly installed-snubber, seal-replaced, spring replaced, in high radiation area, in high temperature area, etc...). The requirement to monitor the snubber service life is included to ensure that the snubbers periodically undergo a performance evaluation in view of their age and operating conditions. j These records will provide statistical bases for future consideration of snubber service life.
All safety related snubbers installed or planned for use at prairie Island 1 are hydraulic-snubbers. No mechanical snubbers are used. )
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