ML19317D249

Proposed Revision to Tech Specs 4.18 Re Hydraulic Shock Suppressors (Snubbers)

ML19317D249
Person / Time
Site:	Oconee
Issue date:	08/22/1978
From:	DUKE POWER CO.
To:
Shared Package
ML19317D247	List: ML19317D246 ML19317D249
References
NUDOCS 7911190629
Download: ML19317D249 (4)

Text

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4.18 HyDRAUI.IC SHOCK SUPPRESSCRS (SNU33ERS)

O Applicability Applies to hydraulic shock suppressors used to protect the Reactor Coolant System or other safety-related systems.

Objective To verify that required hydraulic shock suppressors are operable.

Soecification 4.13.1 All hydraulic snubbers listed in Tat le 4.13-1 whose seal sa erial has been demons::sted by operating experience, lab testing or analysis to be compatible with the operating envi ccment shall be visually in-spected. This inspection shall include as a 24 4 mum hycraulic fluid reservoir, fluid connections, and linkage connections to the piping and anchor to verify suppressor operability in accordance with the following schedule:

Number of Suppressors Found Next Required Inoperable Durina last Inscection Inspection Interval

! 0 18 months : 25 %

l 1

12 months t 25%

2 6 months : 25 %

3,4 4 months : 25 %

5,6,7 2 months : 25%

>S 1 month 2 15 %

Note: (1) The required inspection interval shall not be lengthened more than one step per i=spection.

(2) Suppressors may be categorized in two g: cups, " accessible" or "isaccessible", based on their accessibili:7 during reactor operation. These two groups may be inspected independently according o the above schedule. ,

9 4.13.2 All hydraulic snubbert with seal material not fabrica:ed f:cm ethy-lane propylene or other materials demons::sted compatible with the operating environment shall be visually inspected for operabili:7 once every month.

4.13.3 A representa:ive sample of 10 hydraulic shock suppressors or app:cxi-mately 10 percent of the hydraulic suppressors installed, whichever is l less, shall be functionally tested for operabili:7 each refueling outage.

This test shall include verification of proper pistcc mcvement, lockup and blecd. For each suppressor determined to be inoperable, an addi-tional 10 percent or 10 suppressors, whichever is less, shall be :ested until no = ore failures are found or all suppressors have been tested.

Suppressors with a rated capacity greater than 50,000 lbs. are exempted from this requirement.

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Bases All safety-realted hydraulic suppressors are visually inspected for overall inte-grity and operability. The inspection will include verification of proper orien-l tation, adequate hydraulic fluid level and proper attachmen; of suppressor to piping structures.

The inspection frequency is based upon maintaining a constant level of suppressor protection. Thus, the required inspection interval varies inversely with the observed inoperable suppressors. The number of inoperable suppressors found during a required inspection determines the time interval for de nex: required inspection. Inspections performed before that interval has elapsed may be used as a new reference point to determine the next inspection. However, the results of such early inspections perfor=ed before de original required time interval has elapsed may not be used to lengthen the required inspectice interval. Any inspection whose results require a shorter inspectica interval will override he previous schedule.

Experience at operating facilities has shown tha: the required surveillance pro-gram should assure an acceptable level of snubber perfor=ance provided that de seal materials are compatible vi-d the operating enviroc=ent.

Snubbers containing seal material which has not been demonstrated by operating experience, lab tests or analysis to be compatible vid de operating environment should be inspected more frequently (eve _7 month) until material cecpatabilit7 is confirmed or an appropriate changeout is completed.

Examination of defective snubbers at reactor facilities and material tests cer-formed at several laboratories W has shown da nillable gum polyurethane '

deteriorates rapidly under the temperature and scisture conditions present in many snubber locations. Although molded polyurethane exhibits greater resistance to dese condi: ions, it also may be unsuitable for application in the higher temperature environments. Data are not currently available to precisely define an upper te=perature limit for de molded polyurethane. Tab :ests and in plan experience indicate dat seal materials are available, primarily edylene propy-lene c:mpounds, which should give satisfactory performance under de most severe conditicas expected in reactor installation.

To furder increase the assurance of snubba- .bility, functional tests should be perio:=ed once each refueling cycle. These tests will include streking of de snubbers to verify proper piston movement, lock-up and bleed. Ten percent or ten snubbers, whichever is less, represents an adequate sample for such tests.

Cbserved failures on these samples should require esting of additional units.

Those scubbers designated in Table 4.13-1 as being in high radiatics areas or l especially difficult to re=cve need not be selec-u #-- #

c:icnal tests provided operability was previously verified. Scubbers of rated capaci 7 greater than 50,000 lbs. are exempt from de functional testing requirements because of de impractibility of esting such large units.

REFEENCIS Report H. R. Erickson, Bergen Paterson to K. R. Goller, NRC, Octocer 7, 1974

Subject:

Hydraulic Shock Sway Arrestors J @l]Lrb h I6 U[b)h@M0Qf 7ld <,

- % lummm u 4.18-2 -

TAllt.E 4. I8-I '

lin i t 2 Sa fel y itelat eil Sliock Suppa essors (Saiulitiers)

Suppressors Suppressors Suppressor in liigt Especially inaccessi!>le lluring Itailiat ion Area Sket clifilanger No. Systens liif ficult Normal Operation I)uring Sliutiloun*

To itemove 2-124 tlain Steaua I.ine (OIA) X 2- 125 ( AEll) X 2-127 2-128 2-129 2-l'10 X 2- 132 ( A ,ll, C , D) X 2-134 2-135 p 2-147

2- 149 (A611) X

'(* 2-151 2-152 11 2A X 11 8A X 11 211 X 11 811 X 2-941 H. sin St eam flypass t o Contlenser 2-944 (OIA-1) 2-945 2-313S Ilain St cam Supply 1o Auxi!iary Equi gunen t (OIA-3) 2-1309 Hain St cam Siipply 1o EmerEency 2-1322 Feeiluat er Pump Turlaine (OIA-4) 2-1323 2-1324 2-1326 2-1327 2-1329 2-13'l3

TAllI.E 4.18-1 linit 3 Safety itelateil Sliock Suppressors (Snubliers) .

Siippressors Sistigiresso rs Sugilis essor in liigli Especially inaccessible 1)nring Haitiation Area Sketch /llanger No. System 11i 11 icul t Normal Operation lluring Shutilowna To itemove 11 7A liain Fece!wat er 1.ine (03) X 11 611 X ll 40A X 11 411 X 3-1274 Emergency Feestwater 1.ine (03A) 3-1379 3 - 12110 3-5606 p 3-5624 r 3-5628

'(* 11 I A X l

11 11 OTSG l{ccirculation System (04) X 11 46 X 11 SO X 11 5 2 X

~

11 I l{cactor Coolant System (50) X 11 3 X 11 4 X 11 S X 11 7 X .

11 8 X 11 9 X ll 10 X 11 11 X 11 12 X 1: lA X li 2A X 11 :lA X 11 13A X