ML20237D090

Proposed Tech Specs,Improving Tech Spec 3/4.7.8 Re Snubbers. Discussion & Analysis of No Significant Hazards Consideration Encl

ML20237D090
Person / Time
Site:	Catawba
Issue date:	12/15/1987
From:	DUKE POWER CO.
To:
Shared Package
ML20237C832	List: ML20237C830 ML20237D090
References
NUDOCS 8712230040
Download: ML20237D090 (15)

Text

_ _ _ _ _ _ _ _ _ _ _ _

E 9

• ATTACHMENT 1 TECHNICAL SPECIFICATION CHANGES f

l l

l

$[k22gggy $$ g3 P

No 4 <vges %

PLANT SYSTEM.

3/4.7.8 SNUB 8EM LIMITING CONDITION FOR OPERATION 3.7.8 All snubbers shall be OPERABLE. The only snubbers excluded from the-requirements are those installed on nonsafety-related systems and then only if their failure or failure of the system on which they are installed would have no 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 .l system inoperable and follow the appropriate ACTION statement for that system. l SURVEILLANCE REQUIREMENTS 4.7.8 Each snubber shall be demonstrated OPERABLE by performance of the

~

v following augmented inservice inspection program i.n lieu of the requirements 2 -

of Specification 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. The first inservice visual inspection of each type of ,

snubber shall be performed after 4 months but within 10 months of  !

commencing POWER OPERATION and shall include all hydraulic and mechan-ical snubbers. If less than two snubbers of each type are found in- '

operable during the first inservice visual inspection, the second inservice visual inspection shall be performed 12 months 25% from the date of the first inspection. Otherwise, subsequent visual in-spections shall be performed in accordance with the following  ;

l schedule:

No. of Inoperable Snubbers of Each Subsequent Visual Type Found Durino Inspection Inspection Period *#

0 18 months 25%

' 1 12 months 25%

2 6 months 25%

3,4 124 days 25%  !

5,0,7 62 days ! 25% l 31 days ! 25%

8 or more l

' "Tne inspection interval for each type of snubber shall not be lengthened more than one step at a time unless a generic problem has been identified and corrected; in that event the inspection interval may be lengthened one step the first time and two steps thereafter if no inoperable snubbers of that type are found.

1. The provisions of Specification 4.0.2 are not applicable.

'3/4 7-19 4

CATAWBA - UNITS 1 & 2

l-PLANT SYSTEMS

)

SURVEILLANCE REQUIREMENTS (Continued)

c. Visual In iteria y al impactions shall verify that: (1)(herearenovisibleindi-cations of damage or impaired OPERABILITY,g(2) attachments to the foundation or supporting structure are functional, ;nd (O f;;tenere Or ett;;h;.;nt ;f th; ;n;.:2;r t; th; ;r;;n:nt :nd t; th; :ndt r

n;h r;;; cr; An:ti;;;;. Snubbers which appear inoperable as a result of visual inspections may be determined OPERABLE for the pu

, _< a of as+ Alichiner the aest vi d in;p;;t'vu 'nt;ivil, pivvioso that: (1) the cause of the rejection is clearly established and reme-died for that particular snubber and for other snubbers (regardless of type) that may he generically susceptible; and (2) the affected snubber is functionally tested in the as-found condition and deter- i mined OPERABLE per Specification 4.7.8f. When a fluid port of a hy-draulic snubber is found to be uncovered, the snubber shall be declared inoperable and may be determined OPERABLE via functional testing only if the test is started with the piston in the as-found setting extending the piston rod in the tension mode direction. All snubbers connected to an inoperable common hydraulic, fluid reservoir shall be counted as inoperable- snubbers.

d. Refuelino Outace Inspections At each refueling, the systems whlch have the potential for a severe dynamic event, specifically, the Main Steam System (upstream of the 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 the case of a severe dynamic event, mechanical snubbers in that system which experienced the event shall be inspected during the refueling. outage to assure that the mechanical snubbers 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; or (2) eval-uation of in place snubber piston setting; or (3) stroking the mechanical snubber throu G its full range of travel. If one or more mechanical snubbers are found to be frozen up during this inspection, I those snubbers shall be replaced or repaired before returning to power. The requirements of Specification 4.7.8b. are independent of the requirements of this specification.

e. Functional Tests Dur' e first refueling shutdown and at least once per h I ereafter during shutdown, a representative sample of snubbers e+

h tys; shall be tested using one of the following sample plans.

as The large-bore steam generator hydraulic snubbers shall be tre I

CATAWBA - UNITS 1 & 2 3/4 7-20 e _ - _-_-

PLANT SYSTEMS f SURVEILLANCE RFOUIREMENTS (Continued)  ;

e. Functional Tests (Continued) a separate type (population) for functional test purposes. A 10%

random sample shall be tested at least once per 18 months during refueling with continued testing based on a failure evaluation. The sample plan shall be selected prior to the test per a cannot-be-ch.anged during the test period. The NRC Region fied in writing of the sample plan sel cted f r e h ; nutter typ: administrato prior to the test period or the sample sed in the criac-t W period shall be implemented:

~

1) At least 10% of all snubbers snall be fupr<tfo'n'a15y-te[ ither in place or in a bench test. For each iinubber of : typ: that i does not meet the functional test acce tance criteria of Sp $

cification 4.7.8f., an additional 10% o snubber be functionally tested until no more failures are found or until all snubbers have been functionally tested; or

2) A representative o r!e--ci ali snubbmr; 9 11 5 functionally tested

• cordance with Figure 4.7-1. "C" is the umber of ubbers f : typ: ,found not meeting the acceptance requi -

ents of Specification 4.7.8f. The cumulative number of snub-bers tested is denoted by "N". At the end of each day's test-(. ing, the new values of "N" and "C" (previous day's total plus current day's increments) shall be plotted on Figure 4.7-1. If i

,  :: :ny ti : th; point p htted f lls in the "C ject" r ;i n, :11

nubber: Of th:t type thcl' be functionally t :ted. If at any time theI point plotted falls in the " Accept" region, testing of i snubbers ;f th:t typ: may be terminated. When the point plotted lies in the " Continue Testing" region, additional snubbers e  ;

th t type shall be tested until the point falls in the " Accept" racion cr the "R ' q r:ghn, or all the snubbers f th:t t3p have been teste i

An initial representative sample of 55 snubbers shall be fun

'onally tested. For each snubber type which does not m the etional test acceptance criteria, another sa. of at least one lf the size of the initial sample s be tested "

until the tot umber tested is equal to t initial sample size multiplied by factor, 1 + C/2 - ere "C" is the number of snubbers found which not mee e functional test accept-ance criteria. The results his sample plan shall be plotted using an " Accept" e wn ' follows the ecuation N = 55(1 + C/2). Each ubber point ld be plotted as soon as the snubb s tested. If the poi lotted falls on or below the "Ac- "

line, testing may be termina l' the point plo d falls above the " Accept" line, testin st continue until e point falls in the " Accept" region or all the ' bers hat type have been tested.

1 CATAWBA - UNITS 1 & 2 3/4 7-21 l _ _ _ _ _ _ _ _ _ - - _ _ - -

PLANT SYSTEMS SURVEILLANCE RE0VIPEMENTS (Continued) (

e. Functional Tests (Continued)

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 provided all snubbers tested with the failed equipment during the day of equipment failure are retested. The representative sanple selected for the functional test sample plans shall be random-ly selected from all snubbers and reviewed before beginning the test-ing. The review shall ensure, as far as practicable, that they are representative of the various configurations, operating environments, range of size, and capacity of snubbers. Snubbers placed in the same location as snubbers which failed theJ gevinns functional test shall be retested at the time of the nptetunctional test but shalT~not4e included in the sample plan. Y during the functional testing, add 1 tional sampling is required .ue[tc fa ;m e of cc,1y or,c typt ;f = f .

-bee;- the functional test rent 11 be reviewed at that time to

~ x determ,icae if additiop l y nlas should e 'mited-tcL.the typ cf

.{bq sn yers hich h;s fm. ad the functional t h l O <Nctanea fo  % cr s F ci ic runctional Nst F $4are ri ter~i a ede ideo *hed b) i -

l *lurc. m od.e.

The snubber functional test shall ve-ify that:

1) Activation (restraining action) is achieved within the specified f l

range in both tension and compression, except that inertia de-

, pendent, acceleration limiting mechanical snubbers may be tested to verify only that activation takes place in both directions of travel;

2) Snubber bleed, or release rate where required, is present in both tension and compression, within the specified range;

3) For mechanical snubbers, the force required to initiate or maintain motion of the snubber is within the specified range in both directions of travel; and

4) For snubbers specifically recuired not to displace under continuous load, the ability of the snubber to withstand load without displacement.

Testing methods may be used to measure parameters indirectly or parameters other than those specified if those results can be correlated to the specified parameters through established methods.

g. Functional Test Failure Analysis l An engineering evaluation shall be made of each failure to meet the functional test acceptance criteria to determine the cause of tne

( MN failure. The results of this evaluation shall be used, if applicable, T-90% in selecting snubbers to be tested in an effort to determine the OPERABILITY of other snubbers irrespective of type which may be g7 sub,)ect to the same failure mode.

NN CATAWBA - UNITS 1 & 2 3/4 7-22

I. .

p

i. ,

INSERT FOR PAGE 3/4 7-22 l

An independent test failure mode group consisting of all unacceptable snubbers that have a given failure mode, and all other snubbers subject to the same failure node, may be separated for continued testing apart from the general populaticn of snubbers. However, all the unacceptable snubbers in this failure modo group shall be counted as one unacceptable snubber for additional testing in the. general population. Once the test failure mode group has been set apart for testing purposes, then the unacceptable snubbers which define the test failure mode group shall be counted as unacceptable snubbers for continued testing in the test failure mode group. Any additional unacceptable snubbers found in the test

! failure mode group shall be counted for continued testing only for that test L failure mode group.

l l

l' l

.r _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _

y.

• ,s

'4., -

7-)

' No Gigg 7~o T~HLr fAFE ?

Y n PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued)  ;

g. Functional Test Failure Analysis (Continued)

\a For the snubbers found inoperaole, an engi.neering 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. s i r If any snubber selected for functional tetthg eithm fails to lock up or fails to move, i.e. , frozen-in place, the cause will te evaluated and, if caused by manufacturer or Grign deficiency, el) snubbers of the same type subject to the site 63fect shall be futic- i tionally tested. This testing requirement saa?l be independent of the requirements stated in Specification 4.7.ta. fcr snubbers nof-meeting the functional test acceptance criteria. (.

h. Functicnal Testing of Repaired and Reol..a.c.ad_[n.ubbers

.~ .

Snubbers which fail the visual inspection or td?. funtthnal test acceptance criterii shall be repaired or replaced. Replacesant snubbers and snubbers which have epairs which might affect the .

functional test results ' hall s be* tested te meet the functional- test -

criteria before installation in the unit. Mechanical snubbers shall have met the acceptance criteria suusequent to their most recent service, and the freedom-of-motion test must have been performed within 12 months before being installed in the unit.

4

i. Snubber Service Life Program The service performance of all snubbers shall be monitored. If a service lifetime limit is associated (established) with any snubber (or critical part) based on manufacturer's information, qualification tests, or historical service results, then the service life shall be monitored to ensure that the service life is 'not exceeded betweAn surveillance inspections. Established snubbdr service life shall be extended or shortened based on monitored test results sad failure history. The replacements (snubbers or critical parts) shall be docu-mented and the documentation shall be retained in accordance with Specification 6.10.2.

l f

I CATAWBA - UNITS 1 & 2 3/4 7-23

.t, 10

(

9 s

8 l n

7. )-- - "

I  !,

' N L

' ' n 6 '

Of' v

is C 5 '

f b' ,

^N l

4 I CbNTINUE 3

IL ,

TESTING / '

, y MT .

9,/

ACCEPT

! 1 f

/t 0 10 20 30 40 50 60 70 80 90 100 N

'm FIGURE 4.7-1 SAMPLE PLAN 2) FOR SNUBBER FUNCTIONAL TEST CANESA-UNITS 1AND2 3/4 7-24

1 PLANT SYSTEMS l l

BASES SNUBBERS (Continued) i The visual- inspection frequency is based upon maintaining,a constant level of-snubber. protection during an earthquake.or-severe transient. . Therefore3. the. _

required ' inspect' ion interval'v' aries inv'ersely with the ' observed. snubber f ailures and is determined by the number of inoperable snubbers found during an inspec-tion. In order to establish the inspection frequency for each type of snubber, it was assumed that the frequency of snubber failures and initiating events are constant with time and that the failure of any snubber on that system could i cause the system to be unprotected and to result in failure during an assumed initiating event.' Inspections performed before that interval has elapsed may l be used as a new reference point to determine the next inspection. However, the r'hsults of such early inspections performed before the original required time interval has 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. The acceptance criteria are to be used in the visual inspection to determine OPERABILITY of the snubbers.

To provide assurance of snubber functional reliability, ,e of,Ywo ttr;;

f functional testing methods are used with the stated acceptanc criteria:

1 \

1. Functionally test 10% of a type of snubber with an additional

_ 10% tested for each functional testing failure, or x

. Functionally test a sample size and determine sample acce e -ee rejecti;n using Figure 4.7-1,mut

2. "uncti:n:ll3 :::: ; r;;r;; cat ti.; ;;; sic sir; and dctcr,in  ;;m;!;

n;; ;r r;j;;ti;n .;i ; tr,; ;;;;;d ;;;; tier Figure 4.7-1 was developec using "gald's Sequential ProDaD161Ly Nat10 Plan" as described in " Quality Control and Industrial Statistics" by Acheson J.

Duncan.

Permanent or other exemptions from the surveillance program for individual snubbers may be granted by the Commission if a justifiable basis for exemption is presented and, if applicable, snubber life testing was performed to qualify the snubber for the applicable design conditions. Snubbers so exempted shall be listed in the list of individual snuhbers indicating the extent of the exemptions.

)

CATAWBA - UNITS 1 & 2 B 3/4 7-5

ATTACHMENT 2 DISCUSSION AND ANALYSIS OF l NO SIGNIFICANT HAZARD CONSIDERATIONS i

e

i CHANGE 1 - DELETION OF SURVEILLANCE 4.7.8e.3)

Surveillance Requirement 4.7.Be.3) presents one of three options to be selected for use as a snubber sample plan.

This particular test plan has never and will never be used at Catawba. The other two plans under functional testing; the 10% plan (c.1) and the 37 plan (e.2),

will be sufficient for any testing at Catawba. Likewise in the most recent draft of OM-4,. Revision 2 draft 5, the 55 sample plan has been deleted.

10 CFR 50.92 states that a proposed amendment involves no significant hazards considerations if operation in accordance with the proposed amendment would not:

l (1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

(1) The proposed amendment does not involve an increase in the probability or. I consequences of any previously evaluated accident. The probability and/or consequences of an accident previously evaluated remain unchanged. Deletion of the 55 functional test sample plan (Surveillance 4.7.8e.3) will not have an affect on the design or operation of the station since this plan has never been implemented.

(2) The proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated because the amendment will not result in a change to the design or operation of the q station. '

All snubbers will still be required to be operable and appropriate snubber inspections will continue to be performed. As such, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

(3) The proposed change will not result in a significant reduction in a margin of safety.

Removing surveillance 4.7.8e.3) will result in the deletion of one of three sample options. As such, the requirements of the specifications will be more restrictive.

l l

l

CHANGE 2 - DELETION OF TIIE ' REJECT' LINE This change would allow deletion of the reject line from Figure 4.7-1 and in the 37 functional test sample plan (Surveillance 4.7.8e.1).

The justification for this has already been evaluated for the McGuire Technical Specification change issued September 30, 1985. This change has also been agreed upon by the OM-4 working group for Revision 2 of the OM-4 standard.

Deletion of the " REJECT" line will remove the possibility of rejecting a good population of snubbers which would require unnecessary testing of the total population of approximately 1600 snubbers.

10 CFR 50.92 states that a proposed amendment involves no significant hazards considerations if operation in accordance with the proposed amendment would not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of;a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

(1) Deletion of the " REJECT" line will not impact the probability or consequences of an accident. Deletion of the " REJECT" line will omit the possibility of rejecting a good population of snubbers.without increasing the possibility of passing a bad population. The requirement to continue testing additional samples of snubbers if inoperable snubbers are found will remain in the specifications.

(2) The proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated because the amendment will not result in a change to the design or operation of the station.

All snubbers will still be required to be operable and appropriate snubber inspections will continue to be performed. As such, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

(3) The proposed change will not result in a significant reduction in a margin of safety.

Deletion of the " REJECT" line will remove the possibility of unnecessarily j having to test all of the snubbers at the station. The requirement to test additional samples of snubbers when inoperable snubbers are found will be retained. Therefore this change will not significantly reduce a margin of i safety.

CHANGE 3 - CLARIFICATION OF FAILURE MODE GROUPING The present Catawba Technical Specification addresses failure mode grouping in paragraph g under functional test failure analysis, but does not give any specific direction of how to implement this. A meeting was held on November 10, 1987 with members of the NRC Staff to address this issue. The agreed i upon direction for implementing failure mode grouping is what is being proposed  !

at this time in Specification 4.7.8g. _l J

10 CFR 50.92 states that a proposed amendment involves no significant hazards considerations if operation in accordance with the proposed amendment would not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of  !

accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

(1) Addition of the words describing failure modo grouping is intended to clarify the current practice and therefore has no affect on any previously j evaluated accidents.

(2) The proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated because the amendment will not result in a change to the design or operation of the station.

All snubbers will still be required to be operable and appropriate snubber inspections will continue to be performed. As such, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated. {

l (3) The wording changes to surveillance 4.7.8g. are intended to clarify existing practice. Therefore, these changes will not affect any margin of safety.

1 i

i 4

i i

i

, a CHANGE 4 - DELETION OF 'OF A TYPE' FROM SURVEILLANCE 4.7.8e i This proposed change would allow deletion of the phrase "of a type" in paragraph 4.7.8e.

The use of this phrase penalizes Catawba Nuclear Station when/if they upgrade to a better snubber. It requires a new sample plan be initiated for every type snubber. Our 95/90 confidence level is naintained with one or more than one type of snubber, 1

1 10 CFR 50.92 states that a proposed amendment involves no significant hazards considerations if operation in accordance with the proposed amendment would not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

(1) Deletion of the phrase "of a type" will remove unnecessary restrictions from the snubber specification. The requirement to have all snubbers operable will not be affected by this change, therefore there will be no change to the results of any previously evaluated accidents.

(2) The proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated because the amendment will not result in a change to the design or operation of the l

station.

All snubbers will still be required to be operable and appropriate snubber  ;

I inspections will continue to be performed. As such, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated. .

1 (3) The proposed change will not result in a significant reduction in a margin of safety.

l l The entire population of snubbers will be adequately maintained independent of how many different " types" may exist. Adequate testing and inspection will still be required to ensure that the snubbers will remain operable.

I 4

CHANGE 5 - DELETION OF REQUIREMENT TO INSPECT ATTACilMENT !!ARDWARE Surveillance 4.7.8c. Visual Inspection Acceptance Criteria goes beyond inspection of the snubber and its attachment to supporting structures. It also requires inspection of the attachment hardware. This inspection is already under the requirements of ASME Sect XI IWF, which the OM-4 working group has acknowledged.

This change.is recommended so that unnecessary man-rem and man-hours can be saved.

10 CFR 50.92 states that a. proposed amendment involves no significant hazards considerations if operation in accordance with the proposed amendment would not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margin of safety.

(1) Deletion of the requirement to inspect attachment hardware will remove an unnecessary burden from the snubber specification. This inspection is already required under Section XI of the ASME Code. The Section XI inspection will be performed as' required, thus this change has no affect on any previously evaluated accident.

(2) The proposed change will not create the possibility of a new or different  !

kind of accident from any accident previously evaluated because the amendment will not result in a change to the design or operation of the station.

All snubbers will still be required to be operable and appropriate snubber inspections will continue to be performed. As such, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

i (3) Deletion of the requirement to inspect the snubber attachment hardware will  ;

eliminate an unnecessary amount of inspection. Since this inspection is l required to be performed per Section XI of the ASME Code, deletion from the i specifications will not result in a significant reduction in a margin of safety.

- - _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _