ML20126G566
| ML20126G566 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/13/1981 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-81-01, IEB-81-1, NUDOCS 8103270044 | |
| Download: ML20126G566 (12) | |
Text
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1 4
s' 400 Chestnut Street Tower II March 13, 1081 cn S>
Mr. James P. O'Reilly, Director
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Office of Inspection and Enforcement
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U.S. Nuclear Regulatory Commissior)-
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-Q Region II - Suite 3100 cy 4 %
101 Marietta Street-Atlanta, Georgia 30303
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Dear Mr. O'Reilly:
NA g rT to 0F ISPE ON AND ENFORCEMSMT BULLETIt! 81 0-25
-2f0 -296 BROWNS PERRY NUCLEAR PLANT In response to your January 27, 1981, letter to H. O. Parris which transmitted OIE Bulletin 81-01, enclosed are the results of our investigations for our Browns Ferry Nuclear P1nnt.
As stated in'our responses to items 2.c and 3.c, TVA has had an ongoine insoection-crogram for these snubbers and has sufficient confidence ir the condition of these snubbers to request exemption from any additional testing until the next scheduled refueling outage of each unit.
'le estimate that 200 man-hours will be required to fully implement the proposed actions.
If you have any questions regarding this matter, please call Jim Domer at FTS 857-2014 To the best of my knowledge, I declare the statements contained herein are complete and true.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Berulation and Safety Enclosure cc:
Mr. Victor Stello, Director (Enclosure)
Office of Inspection and Enforcement 1
U.S. Nuclear Regulatory Commission Washington, DC 20555 f
82M N j
s ENCLOSURE O
RESPONSE TO IE. BULLETIN 81-01
- BROWNS FERRY l NUCLEAR PLANT D00KETENOS. 50-259,'-260, -296 Actions-to be Taken hv. Licensees of Onerating Rnactown:
i ITEM 1 Within.30 days of the issuance date of this bulletin, all normally-
. i accessible
- INC mechanical snubbers installed on safetv-related systems or in storPge shall,be visita11y. examined and tested as follows:
a.
Perform a visual examination for damage.and, without causing.
the system to be inoperable except as permitted by the facility-technical specifications,-verify that the snubbers have freedom of movement by performing a manual test over the range'of the l
' stroke in both compression and tension.-
b.
Perform an operability test to confirm that (1) activation (restraining action) occurs in both' compression and. tension and j
(2) the drag forces are within the specified range in both L
compression and tension.
The tests shall'be performed on al'
?nubbers in storage and on a representative-sample (10% of the total of this type of-anubberLin use in the plant'or 35, which ever is less) of the normally accessible snubbers that are in service and can be individually removed without causing the
.tystem to be inoperable,- except as permitted by the facility t ech-ical specifications.
For each snubber that does not meet the test acceptance criteria, an additional representa-tive sample (as defined above) of.this' type of snubber shall be tested.
For each of these additional snubbers that do not 1
4 meet the test acceptance' criteria, another representative.
sample of this type of. snubber shall be tested.
This cycle
)
shall be repeated until no more failures have been found or until all snubbers of this' type have been tested.
-The I
samples-should be made uo of snubbers representing the various sizes.
l c.
Snubbers which have been examined and tested in a manner comparable to Items la and 1b above within the last six months may be exenpted.
d.
If any failures are identified in Items la or 1b above, t a'< c corrective action and evaluate the effect of the failure on the system operability pursuant to the facility technical specifications for continued operation.
e.
If failures are identified in Items la and 15 above, and if INC snubbars are known to be located in any inaccaseibla areas, a plant shutdown chall he performed within 30 days after the discovery of the first inoperable snubber and inspections conducted in accordance with Item ?a and 2b belou, unless justification for continued operation has been provided to i
the 1RC.
'"Mormally accessihie" refers to those areas of the plant that can be entered during reactor oceration.
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RESPONSE
There are no nornally accessible INC mechanical snubbers installed on safety-related systems or in storage at Browns Ferry Nuclear Plant. Therefore this iten does not apply to Browns Ferry.
ITEM 2 Visually examine and test all inaccessible INC mechanical snubbers installed on safety-related systems at the next outage of greater than five days,.
duration as follows:
a.
Visually examine and manually test all inaccessible snubbers.as described in Item lu above.
b.
Perform an operability test on a representative sample of inaccessible snubbers as described in Item ib above.
Snubbers which have been examined and tested in a manner comparable c.
to Items 2a and 2b above within the last six months may be exempted.
d.
If any failures are identified in Items ?a or 2b above, take corrective action to evaluate the effect of the failure on system o.perability,
pursuant to the facility technical specifications for resuming operation,
RESPONSE
Each of the three units at Browns Ferry contains 14 INC mechanical snubbers installed inside containment on the reactor veasel level control line (Yarway column).
a.
These snubbers are stroked each refueling outage in compliance with plant instructions.
b.
A representative sample (160 of the INC mechanical snebbers will be tested for activation and the drag force will be measured during the next inspection, c.
Attached is a tabulation of the results of previeus inspections of mechanical snubbers performed in recent years at Browna Ferry.
The tabulation shous that all of the INC snubbers have been stroked cach refueling outage since they vere installed. We believe this tabulation will orovide the info rmation that is the stated purpose of the bulletin and have sufficient confidence in the condition of the snubbers to requent e::emption f rom any additional testing until the next scheduled refuelin-g outage of each unit.
d.
Any failure of the INC mechanical snubbers to meet acceptance et 3 teria will be evaluated and appropriato corrective action taken.
y
ITE!! 3 Provide a schedule for an inspection program covering mechanical snubbers produced by other manufacturcs.
As a minipum, this inspection program shall:
a.
Include all snubbers installed on safety-related systems; b.
Include the visual examination and manual test described in Item la above for all snubbers; c.
Snubbers which have been examined and tested in a manner comparable to Item 3b above within the last twelve months may be exempted; d.
Require the corrective action and evaluations described in Items Id and 2d above; and e.
Be completed prior to the completion of the next refueling outage.
Plants which are currently in a refueling outage should perform the visual examination and manual tests of inaccessible mechanical snubbers before resumption of operations unless some other basis for assurance of snubber operability is provided to the NRC.
RESPONSE
Snubbers manuf actured by Pacific Scientific Compan f, Kin-Tech Division, are installed on the safety-relie f valve tailpipes and Main Steam Lines A
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and D on all three units at Browns Ferry.
a.
No other safety-related systems except as coveren.by rtsponse 2 above have any mechanical snubbers installed, b.
Visual examinations and stroking of snubbers have been performed on mechanical snubbers since they were installed at Browns Ferry.
The requirements of these examinations and stroking ccmply with the requirements of item la.
c.
The tabulation of the results of the visual examination and stroking of the PSA snubbers is also included in the attached tabulation.
Considering the 100 percent acceptance history of the snubbers which have been e::cmined we propose to examine and test at the next s'-
fuelin; outage of each unit any snubbers which have not previously been examined and tested, and to continue a surveillanca program in accordance with the plant instructions or Technical Specifi-cations, whichever may govern.
d.
Any failure of the PSA mechanical snubbers to meet the acceptance criteria will be evaluated and the appropriate corrective actica
- taken, e.
There are no units currently in a refueling outanc.
The ner:t refuct-ing outase is scheduled to begin in April 19S1 for unit 1, in September 1931 for unit 3 and in :tarch 1982 for unit 2.
Examinations and tests as proposed in response 3c above will be performed during thosu outages.
o ITEM 4 Submit a report of the results of the inspections, testing and evaluation requested in Item 1 to NRC within 45 days o,f the issuance date of, this bulletin.
Report the results of the inspections, testing and evaluation requested in Item 2 within 30 days after the inspection and testing have been completed.
The response to Item 3 shall be submitted within 60 days 3
of the issuance date of this Bulletin. The results of the inspections perf ormed for Item 3 shall be submitted within 60 days af ter the completion of the inspection.
The reports shall contain the following:
a.
A description of the visual eraminations and tests performed, b.
Number of snubbers examined and tested.
Grouping by manufacturer name, model nunber,'and size is acceptable.
i c.
Number of f ailures identified; manufacturer name, model number, size, mode of failure, cause of failure, corrective action, snubber location, effect of f ailure on plant and system safety, and justification for continuing or resuming operation, i
d.
The above information shall also be provided for the snubbers j
exempted by Items Ic, 2c, and 3c above.
i
RESPONSE
Since itet 1 for acc.cssible INC snubbers does not apply to Drowns Ferry, no further report 1. required for that item. The attached tabulation is submitted as an interim report for item 2 on inaccessible INC mechanical snubbers and on item 3 for other mechanical snubbers.
The subsequent reports will be submitted on a timely basis in accordr,nce with the responses above, a.
The examinations and tests previously conducted and reported in attachment 1 were performed in accordance with plant instructions.
The pertinent pages of the current instruction are included as attachment 2.
These instructions will be revised as necessary to comply with item 2b.
b-d. The attached tabulation providen the de* ail requited to supply the information requested in the items.
Thrcugh the voluntary program that TVA has maintained at Browns Ferry the con?.ition of mechanical snubburs on safety-related systems has been mon-l it ored through the years, and the resulta are recorded on the plant inst ac-i tion data sheets filed at the plant.
We 'enlleve this is an effective program i
and have extcaded it to other planta.
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.s.
,e BROWNS FERRY NUCLEAR PLANT FIECllANICAL SNUBBER FUNCTIONAL TEST llISTORY 1";IT DATE SUUBliER TESTED'-
NUhlBER FIAINTENANCE MFC.
NO.
FAILED INSTRUCTION /CO>Df ENT 1&2 8-74 INC k4 100%
5 Reported in NRC IE Bulletin 14 100%
11 81-01 as " Unit 2 & 3" l
JNIT 16 2 FIRE OUTAGE DECAN 3/75 - NEW VERSION INC INSTALLED AND PSA INSTALLED ON
'1SRV TAILPIPES 4/76 - RESTART FR031 FIItE OUTAGE 8/76 JNIT 3 C0:f!ERCIAL OPERATION - 3/77 1
9-77 PSA 11, 25%
0 FDt1 36 INC 14 100%
0 2
5-78 PSA 14 25%
0 tDi[ 36 INC 14 100%
0 3
9-78 PSA 7
15%
0 101I 59D INC
_ 14 100%
0 1
11 -78 PSA 7
15%
0 FthI 59D INC 14 100%
0 2
5-79 PSA 5
10%
0 FD11 59D INC 14 10V*:
0 3
9-79 PSA 7
15%
0
>Dt!. 59D INC 14 100%
0 1
1-80 PSA 7*
15%
0 tD11 590 INC 14 100%
0 2
11-80 PSA 46 100%
0 FDil 59D INC 14 100l:
0 3
12-d0 PSA 41 90P.
0
>Dit 39D INC 14 100*'
0
- UNIT 1 (2-30) 53
'A PIPE CLAYP NUTS STARED - WOI:KORDER 000-9L90 NOTE:
1.
All INC Snubbers are SISAV, size 1 2.
Unit 1, 52 size PSA-10 1 size PSA-3 Unit 2, 46 size PSA-10 Unit 3, 48 rite PSA-10
-t l-C 7.0 ALARA Censiderations (Continued) ts 7.2. Compare pctsonnel exposure rates and attempt to use those people u.l I
vith the least exposure.
8.0 Instruction C
8.1 Cencral Surveillance Requirements
-a
.J 8.1.1 Yarway columns in each unit' arc equipped with a total of 14 International Nuclear Safe Guard Corporation snubbers.
All,.
0 (100%) of'these snubbers are to be tested during the refueling
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cutage of the unit in which they are installed.
A 8.1.2 All steam relief valve piping and the main. steam liacs A and
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D in the drywell are equipped with Pacific Scientific snubbers as follows:
. Number i f Snubbe rs Installed L*
Unit 1 Unit.2 Uni: '.
Fd On relief valve piping
- 49 42 4 **
OM MS lines A and D 4
4 4
- 53 46 45
.h, A sufficient number of snubbers shall be tested each refueling
)
outage ao that all snubb 'rs will be tested within ten-year perie d
For annual refueling outages ten percent '(5 snubbers) and 7j for 18 months betueen refueling outages 15 percent (7 cnubbers}
are to be tentcl.
Durtng the end-of-cyc1c-test al; snubbers t h., t hav. not previously been tested utt.hin the prevleua ten-year period are to be tested.
To assure that representa tve sampluu o f naub'aerc in the system are testad, they are to be tented in the sequence in which they are listed en the iata shenta (the exact sequence ls not required withta a batch).
7 Figure 2 (pace 22) is included as an overall location pl:n and the in.!Lvidual installations are shown on pages 23
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9.
Test (n,t
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9.1. 'S'e c Cau tio n.' : International Mucicar Safe Guard Corporation.snubbcrs on the two.Yarway columna are to be observed for freedom of moven;cnt n
.d by moving the' piping with the snubbers attached. Move-the pipe in d'Ifferent directions in order to more'directly. activate.cach -
7
, f' snubber of the cluster. The snubbers may be observed on'the two
(
vertical 3/4-inch pipes at the two.locationsincar ch'c core spray u.
lines. cn the third and foucth cicvations in the drywell.
If'the action of ' the snubber is in doubt, it is to. be disconnected and stroked separata from lhe line.
'1 1
CAUTION: Do not move Yaruay piping 1to ' an cr.treme degrec at-j locations remote from snubber attach = cats.
j
'I 1
9.2 If any of the snubbers-do not travel through its full stroke or has been damaged, fit is to be replaced by.a snubber of the saac i
Stores p'ior to startup of tt t unit.
configuration from Icue:
r i
a 9.3 Pacific Scientific snubbers are to be tested as follows:
l j
9.3.1 See Caution.
Disconnect the snubber'from its attachment j
by removing the four bolts. from the mounting flange (refer i
u 1
to Figure 1.)
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CAUTION:
Do not rotate one end of any Pacific Scientific snubber relative to its other end.
Thic twisting will 3) dr. mage internal parts.
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Tectinn Continued) 9.3.
(Coatinued) 3
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9,3.2 Swing the attachment and/or the snubber to the side so that t;he snubber may be v.oved through its six-inch stroke in both directions.
If the attach:nent will not pivot su f fic ien t ly,
3U the loch nut on the thread 2d extcacion may be locacned and the extcasion ser:. cd in to provide cicaranca, if so equipped.
It these pro.c edur u do not provide sufficient clearan:e, the t1
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pin conne ct Lag :.hc cteau:.nent to the lug T.a : be removed, usin.;
bar or sof t-f aced hat:::er to prevent m. rring the e :d a brac:
r-db Of the pin.
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e 9.
Tecting (Continued) r, -e U
9.3 (Continued) q 9.3.3 See Caution. Move the snub ~ocr through its full travel in 4a both directions, applying force by hand attempting to increase ff the speed of the snubber.
Note whether the snubber resists increaced speed with the force applied and whether it travels A
cmoothly thrcunh the full six-inch stroke.
CAUTION:
Slow.the snubber speed bcCore it reaches the end
' q of its stroke.
The internal parts of the snubber
[,3 rotate at high rates of speed, and coming to a cudden stop at the end of the stroke can cause q
damage to the snubber.
g 9.3.4 Snubbers which lock-up preventing the full six-inch stroke 43 or moye without resictance, are inoperabic and are to be J
replaced with new snubbers of the sene configuratio'n from r
J Power Store: prior to startup of the unit.
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,. NOTE:
The PSA-10 Saubbers originally installed re a model not currently manuf actured by Pacific Scientific.
They are painted with white epoxy and are rated at 10,000 pounds design 1 cad.
The sparcs in Powcr Stores
]
- - are the later. design which have a rinc-nicket cad s
protective coating and have a 1s,10T pound design rating. ' These snubbers are dimensiunally and functionally interchangenbic.
9.3.5 When a Pacific Scientific unnbber is determined to be inoperable r7
'Ob an additional refueling interval batch of snubbera is to be El tested.
For each cnubber deterr.Lne J to be inoperabic an
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addit;cual be.teh of snubbers shall be tested until no additi"nal C
d snubber; f all er all enutbers have been tested.
(The snubbera tected durin,; the acnt refueling outage chal'. be inscquence li atter any snuLburc tested in cocplian:c with this parasraph-)
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l 10.
Return to Service m
10'.1 Upon completion of the functional test bring the snubber and a
its attachment back into align =ent and into contact with each' I
other.
(If an attachment pin has been removed be sure it is
' free of burs and coated'with an approved anti-scized compound *
}{d I
before reinstallation.). Note the cold position setting as indicated by " cold setting marks" (figure 1) paint stenciled a
on the snubber.
The line through the middle of the "3" should
[
be aligned with the edge of the dust tube since the cold position setting of all these snuhbcrs is "midrenge" according to the Ig detail installation drawings.
If the cold position setting is 5
not "3," and the snub 5cr has an adjustabic extension, adjust J
the extension to achieve the proper cold position setting. Mauy b
[a of the installations do not have sny adjustment and the as-found reading is to be recorded.
10.2 Make sure the locking tab is on the balt, apply an approved anti-
]
seized coupound* to the threads, and thread the bolts through the J
attachment into tne flange of tie snubber. Tighten the bolts to l
a y
appr+ximately 40 foot pounds.
Bcnd the lock tab up against a flat of the hex hnad belt and devn over the edge o f the flange to prevent loosening the bolt.
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10.3 Obscr'.e.hc snubber for any evidence o f dam:r,2, tighten any c
extension lock nuts, and cheek the clarp httachment nuts for -
tightncas.
See th?.t lock wires. arc inr,talled on the screws whish hold the dust tubes in place.
Ccacrally observe the anubber and i,
its functi0nia its :ttachments for any condition which would prevent
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'i 10.
Return to Servic__c (Continued)
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10.3 (Continued)
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during its cycle between test, record and take rippropriate action.
.a 10.4 Attach or update a linen tag to the snubber (or snubber location) 2 starting by the person responsible.
Fill out and submit the
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required data sheets.
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