ML20070F384

Proposed Tech Specs 4.7.7 Re Visual Insp of Snubbers & 4.7.7.2 Re Insp Interval & Sample Criteria for Snubbers

ML20070F384
Person / Time
Site:	Davis Besse
Issue date:	03/01/1991
From:	CENTERIOR ENERGY
To:
Shared Package
ML20070F375	List: ML20070F373 ML20070F378 ML20070F384
References
NUDOCS 9103080258
Download: ML20070F384 (10)

Text

Docket Number 50-346

..l.icense Number NPF-3 Serial Number 1904 Attachment Page 6 PLANT SYSTEMS 3/4.7.7 SNUBBERS E LIMITING CONDITION FOR OPEPATION 3.7.7 All safety-related snubbers shall be OPERABLE.

APPLICABILITY: MODES 1, 2, 3 and 4. (MODES 5 and 6 f or snubbers located on systems required OPERABLE in those MODES).

ACTION:

a. With one or more snubbers inoperable: 1. 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, or l.. verify system operability with the snubber (e) inoperable by engineering evaluation within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; or 3. declare the supported subsystem inoperable and follow the appropriate ACTION statement for that system, and, for snubbers which have f ailed either the visual or functional test:

b. Perform an engineering evaluation within 90 days to determine if any safety-related system or component has been adversely affected by the inoperability of the snubber and if the snubber mode of failure has imparted a significant ef fect or degradation on the supported component or system.1 The provisions of Technical Specification 3.0.4 are not applicable for the component or system. '-

SURVEILLANCE REQUIREMENTS 4.7.7 Each snubber shall be demonstrated OPERABLE by the requirements of the following surveillance programs and pursuant to requirements of Specification 4.0.5.

4.7.7.1 Visual Inspection Program 1

Engineering evaluation is not required when a snubber is removed for surveillance testing provided it is returned to OPERABLE status within i the requirements of eeeeee-statement a. I Ac.T i e d 2

Safety-related snubbers are listed in the latest revision of applicable surveillance test procedure (s). Snubbers may be added to, or removed f rom, safety-related systems and their assigned groups without a License Amendment. .

DAVIS-BESSE, UNIT 1 3/4 7-20 Amendment No. 9#. 111 9103090258 Y103v1 PDR ADOCK 05000346 P PDR

__. _ _ _ . . ___ _ . _ _ . _ - .m _ __ _ . _ _ _ - . _ . . _ . _ _ _ _. ____

l Docket Number 50-346 License Number NPF-3 l Serial Number 1904 I Attachment .

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' Pbe WT7SYSTEMS SURVEILLANCE RE0VIREMEh7S (Continued) g a. General Reoutrements v J

.1 1 #$"i .M 7 b-* $ At least once per inspection interval, each group of snubbers in use in the Plant shall be visually inspected

.? i ) in accordance with Specification 4.7.7.1.b and 4.7.7.1.c.

! j f. , j Visual inspections may be perfonned with binoculars, or X l, j g- other visual support devices, for those scubbers that are g s T r. s difficult to access and where required to keep exposure as e d 4 0 _f low as reasonably achievable. Response to failures shall 3 g1 be in accordance with Specification 4.7.7.1.d.

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?A* . Inspection Interva l - ' "--- ' " -it _ - _ _

. C .! q c I .I d3 The inspection interval ::f : ,1: ___:_-__ may be applied

$e !>$ on the basis of snubber groups. The snubber groups may be odi 7 ti

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5 established based on physical characteristics and accessi-bility.

Inaccessible snubbers are defined as those located:

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(a) inside containment, (b) in high radiation exposure 43$ zones, or (c) in areas where accessibility is limited by c

T- physical constraintsz__such as the need for scaffolding.

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DAVIS-BESSE, UNIT 1 3/4 7-21 Amendment No. 94 (6cd page is 3/4 1 2.lo)

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. Dockat Nu2bar 50-346

• Licenso'Husbar NPF-S S2 rial Number 1904 Attachment I"E' 0' TABLE 4.7-5 SNUBBER VISUAL INSPECTION INTERVAL NUMBER OF UNACCEPTABLE SNUBBERS Population Column A Column B or Group Column C Extended Interval Repeat Interval Reduced 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 18 500 36 12 24 750 48 20 40 1000 or greater 78 29 56 109 Note 1:

The next visual inspection interval for a snubber population or group size shall be determined based upon the previous inspection interval and the number of unacceptable snubbers found during that interval. Snubbers may be grouped, based upon their accessibility during pover operation, as accessible or inaccessible. These categories may be examined separately or jointly. However, the licensee must make and document that decision before any inspection and shall use that decision as the basis upon which to determine the next inspection ' interval for that group.

Note 2:

Interpolation batveen population or group sizes and the number of unacceptable snubbers is permissible. Use next lover integer for the value of tF 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 tvice the previous interval but not greater than 48 months.

Note 4: If the number of unacceptable snubbers is equal to er less than the number in Column B but greater that the number in Column A, the next- '

inspection interval shall be the same as the previous interval.

3/4 7-21a

._. . .- .- -- - - - - - - ~ ~ ~ ~ ~ ~ ~ ~

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^ Docket Number 50-346  !

.g License Number NPF-3 /

Serial' Number 1904 Attachment Page 9 Note 5: If the number of unacceptable snubbers is equal to or greater.than'the-number in Column C, the next inspection interval shall-be two-thirds of the previous interval. However, 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 factor that-is one-third of the ratio of the difference between 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 vith the exception that-inspection of inaccessible snubbers may be deferred to the next shutdovn when plant conditions allov five days for inspection.

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3/4 7-21b (next page is 7-22)

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Docket Number 50-346 ,

dicense Number NPF Sarial Number 1904 Attachment Pcge_10 PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued)

c. Acceptance Criteria' A snubber shall be considered OPERABLE as a result of a visual inspection if: (1) there are no visible indica-tions of damage or inoperability, and (2) attachments to the foundation or supporting structure are secure.

d ._ Response to Failures For each snubber unit which does not meet the visual inspection acceptance criteria of Specification 4.7.7.1.c:

Detet ine the snubber OPERABLE by functionally testing the snubber per Specification 4.7.7.2, unless the (hydraulic) snubber was determined inoperable because the fluid port was found uncovered; 0,,R

1. Perform the ACTION specified in 3.7.7a; and

2. Perfor.n-an engineering evaluation as specified in 3.7.7.b.; a_nd ,

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3. adessesse the frequency of group inspection as described in Specification 4.7.7.1.b,'un$ wee the cause of the rejection is clearly established and remedied for that l particular snubber and for other snubbers that may be generically susceptible A snaber nud m% c ostde c4 r vnucce. pidl< Tot pocpe ses b r e WL nshi +e, w no4 s ;se t

e. Transient Event Inspection I^ 5 Poct o ^ W"' l -

i An-inspection shall be performed of all hydraulic and mechanical _ snubbers attached to- sections of systen:s that have experienced unexpected, potentially damaging transients as determined from a' review of operational data. A visual inspection of the snubbers on these systems shall be performed within six months following such an event. In addition to satisfying the visual inspection acceptance criteria, freedom-of-motion of mechanical snubbers shall be verified using at least one of the following: (1) manually induced snubber movement; or (2) evaluation

-of in place snubber piston setting; or (3) stroking

-the mechanical snubber through its full range of travel.

DAVIS-BESSE, UNIT 1 3/4 7-22 Amenda:ent No. f),)A ,111

.' Docket Nunbar 50-346 j

d' License Number NPF-3 Serial Nunbar 1904 Attachment  !

Pare 11 PLANT SYSTEMS I l

SURVEILI.ANCE REOUIPIMENTS (Continued) 4.7.7.2 Functional Test Prorram g

a. General Recurrements At least once per inspection interval a representative sample of each group of snubbersin use in the Plant shall be functionally tested in accordance with Specifications l 4.7.7.2.b and 4.7.7.2.c. Response to the failures shall be in accordance with Specification 4.7.7.2.d.

For all snubbers, functional testing shall consist of either bench testing or in place testing.

b. Insoection Interval and Samole Criteria

, onet acc.essibildy The snubbers may be categorized into groups based on physical characteristics! # pit:_:

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2.__7 :: :.. ..___. .,____1.. __ ___ - ___1. Each group may be tested independently from the standpoint of performing additional tests if failures are discovered.

I eration. Specification 4.0.2.b is no': amol W ' . . . n'e next functiona - tns ah -- 6 m oer 4,7 988 (i.e.,

Maren 14,1990). The a ,

• 4 4.0.2.a is applicable

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DAVIS-BESSE. Unit 1 3/4 7-224 Amencment No. JJJ,136 (Next page is 3/4 7 23)

.. Docket Numb;r 50-346 License Numb 2r NPF-3 Sarial Numbar 1904 Attachment Page 12 li:.0 M..,01 M 3 PLANT SYSTDiS StTRVEILLANCE REOUIREMENTS (Continued)

The inspection interval for functional testing shall be 18 months.

Snubbers which are scheduled f or removal for seal maintenance may be included in the test sample prior to any maintenance on the snubber.

The representative sample shall consist of at least 10 percent (rounded off to next highest integer) of each group of snubbers in use in the Plant. The selection process shall ensure that all snubbers, reprdless of l their accessibility classification, are functionally tested at least once every ten inspection intervals,

c. Acceptance Criteria For hydraulic snubbers (either inplace testing or bench testing), the test shall verify that:

1. Snubber piston vill allow the hydraulic fluid to

" bypass" from one side of the piston to the other to assure unrestrained action is achieved within the specified range of velocity or acceleration in both tension and compression.

2. When the snubber is subjected to a movement which creates a load condition that exceeds the specified range of velocity or acceleration, the hydraulic fluid is trapped in one and of the snubber causing suppression of that movement.

3. Snubber release rate or bleed rate, where required, occurs in compression and tension.

For mechanical snubber in place and bench testing, the test shall verify that:

1. The force that initiates free movement of the snubber rod in either tension or compression is less than the specified maximum drag force.

2. Activation (restraining action) is achieved in both tension and compression within the specified range. l DAVIS-BESSE, UNIT 1 3/4 7-23 Amendment No. 53.M 111

Docket

• Number 50-346- j hke:nse-Number'NPF Seriel.Nunber 1904 Attachment 'h.0RV!E,,,01DiiLY PagaL 13 ' PLANT ' SYSTEMS '

j SURVEILLANCE REQUIREMENTS (Continued)

d. Response to Failures for each inoperable snubber per Specification 4.7.7.2.c:

1. Perform the ACTIONS specified in 3.7.7a and 3.7.7b; and

2. Within the specified inspection interval, functionally test an additional sample of at least 10 percent of the snubber units from the group that the inoperable snubber unit is in.

The- functional testing of an additional sample of at least 10 percent from the inoperable snubber's group is required for each snubber unit determined to be Inoperable to subsequent functional tests, or until all snubbers in that group have been tested; and

3. The cause of snubber failure will be evaluated and, if caused by a manufacturing or design deficiency, all snubbers of the same or similar design subject to the same defect shall be functionally tested within 90 days f rom de termining snubber inoperability. This testing require: ment shall be independent of the requirements in 4.7.7.2.d(2) above.

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= DAVIS-BESSE, UNIT 1 3/4 7-24 Amendment No. 15,94 (Tables 3.7-3 and 4.7-4 deleted. Next Page is 3/4 7-36).

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Doc %et Number 50-346 a, License Number NPF-3 Serial Number 1904-

-Attachment Page 14 Pl. ANT SYSTDiS BASES PI. ANT SYSTEMS ,

3/4.7.' SNUBBERS w g i

All safety-related snubbers are required OPIRABI.E to ensure that the structural integrity of the reactor coolant system and all other safety-related systems is maintained during and following a dynamic event.

Snubbers excluded from this inspection program are those installed on safety related systems for loads other than dynamic or on consafety-related,,and then only if their failure or failure of the system on which they"U*ei nstalled, would have no adverse effect on any safety-related l system during a dynamic event.

Inoperable is defined as:

1. For visual test

a. The fluid no longer is supplied to the valve block, or

b. Mounting pins are disengaged from the snubber,

c. Attachment to foundation or supporting structure is not secure.

2. For functional test

a. The snubber (excluding end anchors, i.e. , pin-to pin) does not meet specified test criteria. .

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y.., su.c I< eack s nvuer +ype ,oa ne. prM m { n[m The visual inspection frequency is based upon maintaining a constant level of snuober protection --- '

to systems. Therefore, the required inspection interval - -

-- - - ' is er=ined by the nuncer of inoperable snubbers found during an inspec- l tio Q Inspections performed before that interval has elapsed may be used as a new reference

.....,...z point to determine the next inspection. Hewevest ges-

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AnyAnspecAEenwhosEresults 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 generi-cally susceptible, and verified by functional testing, that snubber may be exempted from being counted as anoperable. Generically susceptible snubb ers a re those which --- ^ ' - ----' '" - " ^- - '-' --' have the s ame er sMar 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.

DAVIS-BISSI, UNIT 1 2 3/4 7-5 Amendment No. W.111

B. - . - - .

( Docket Number 50-346

--' License Number NPF-3 Serial Number 1904 Attachment, h ,. h h {!fj' []*

Page:15 p g.T SYSTEMS-l BASES  ;

When a snubber is found inoperable through a visual or functional test, an engineering evaluation is performed,- in addition to the determination'of the snubber mode of f ailure, in order to determine if any saf ety-related component or system has been adversely affected by the inoperability of the snubber. Tbe engineering evaluation shall determine vbether or not the snubber mode of failure has imparted a significant effect or degrada-tion on the supported component or system.

.To provide assurance of snubber functional reliability, a representative sample of the installed snubbers vill be functionally tested at 18-month intervals.-- Observed failures of these sample snubbers shall require functional testing of additional' units. When a snubber is found to be inoperable due to failure to lock up or failure to move (i.e. , f roze's in place), the cause vill be evaluated for further action or testing.

In cases vnere the cause of f ailure has been identified, additional

- snubbers that have a high probability for the same type of f ailure or are being used in the same application that caused the failure snall be tested. This requirement increases the probability of locating inoperable snubbers without testing 100*r,of the snubbers.

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Hydraulic snubbers and mecnanical snubbers may each be treated as a

'different entity for the above surveillance programs.

DAVIS-BESSE, UNIT 1 B 3/4 7-Sa Amenament No. 94

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