ML19346A319

Forwards Suppl Response to IE Bulletin 81-01 on Surveillance of Mechanical Snubbers.Surveillance Rept Provided.Addl 235 Manhrs Expended to Take Necessary Corrective Action

ML19346A319
Person / Time
Site:	Duane Arnold
Issue date:	06/01/1981
From:	Root L IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-81-01, IEB-81-1, LDR-81-192, NUDOCS 8106190132
Download: ML19346A319 (12)

Text

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Iowa Electric Light and ther Company LDR-81-192 June 1,1981 p i A.

men a unevr M , og er wm^=a a

,,4lr gf,P,,f %p Mr. James G. Keppler, Director lir!

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!J y9' Office of Inspection and Enforcement h"! N, ,,, .' .h Jgg C" Region III i l E " % .

Nuciear Regulatory Cummission $  % g"t @_, ** 'g//

799 Roosevelt Road ,d m ,, '

Glen Ellyn, IL 60137 M Re: Duane Arnold Energy Center

Subject:

IE Bulletin No. 81-01, Surveillance of Mechanical Snubbers File: - A-63j, A-101a, NRC-2,Bulletin 81-01

Dear Mr. Keppler:

This letter and attachment are provided as an additional response to IE Rulletin No.

81-01, supplementing our response of March 13, 1981 (LDR-81-94).

The DAEC Report on the Surve11'ance of Mechanical Snubbers, attached, provides responses to all items of Bulletin 81-01 with the exception of "Cause of Deficiency" of fo';r (4) of the PSA Mechanical Snubbers. As noted in Table 2, Sheets 1 and 2, those snubbers are being sent to Pacific Scientific for an evaluation to determine the cause of the deficiency. The results of the evaluation will"be transmitted when available.

As requested in your transmittal letter, we have estimated that 1,100 man-hours were expended in review of material, inspections and preparation of reports in response to this bulletin and an additional 235 man-hours were expended taking the necessary corrective action resulting from the snubber surveillance.

This response is truebnd accurate to the best of my knowledge and belief.

LDR/BWR/dmh IOWA ELECTRIC LIGHT AND POWER COMPANY cc: B. Reid K. Meyer ,-

, 3 D. Arnold R. Youngs By s' y e. W. ' . .

L. L1u D. M1 neck Larry U. Roor . ,

D. Wilson 3:.,. , Assistant Vice' President S. luthill D. McGaughy D. Mankin Nucletar Generation ,g NRC Resident Inspector s, K. Eccleston (NRC) 4 i Subscribed and Sworn to Before Me on this U.S. Nuclear Regulatory Commissicn /af day of O t u / , 19 f/

Office of Inspection & Enforcement <

Division of Reactor Operations Inspection

!!ashington , D.C. 20555 [/mf/pof) Yh NLL (A) f NulARY PUBLIC IN ANU tUR IHt. S I Al t; UF IOWA U.S. Nuclear Regulatory Commission c/o Document Management B nch ,Jt)N 0 4 W Washington, D.C. ?&p551 > m aos 33i cet.or n.npr<sa. tansa saaos ass 1398.s4:

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.. l DAEC REPORT ON

.THE SURVEILLANCE OF MECHANICAL SNUBBERS (In response to: NRC IE Bulletin 81-01, Rev.1, dated March 4,1981)

Introduction This report is in response to NRC It Bulletin 81-01, Revision 1, dated March 4, 1981, requiring licensees and permit holders for nuclear power plants to perform a surveillance of all mechanical snubbers installed on safety-related systems.

Item 1: Within 30 days of the issuance date of this bu' .ecin, all normally accessible INC mechanf cal snubbers installed on safety-related systems or in storage shall be visually 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 stroke in both compression anc tension,

b. Perform an operability test to confirm that (1) activation (restraining action) occurs in both compression and tension and (2) the drag forces are within the specified range in both compression and tension. The test shall be performed on all snubbers in storage and on a representative sample (10%

of the total of this type of snubber in use in the plant or 35, whichever is less) of the normally accessible snubbers that are in service and can be individually removed without causing the system to be inoperab,le, except as permitted by -

the facility tachnical specifications. For each snubber that

' does not meet the test acceptance criteria, an additional representative sample (as defined above) of this type of snubber snall b! tested. For each of these additional snubbers that do not 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 samples should be made up of snubbers l representing the various sizes.

l c. Snubbers which have been examined and tested in a manner comparable to Items la and Ib above within the last six months may be exempted.

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d. If any failures are identified in Items la or lb above,. take 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 Ib above, and if INC snubbers are known to be located in any inaccessible areas, a plant shutdown shall be performed within 30 days af ter the discovery of the first inoperable snubber and inspections conducted in accordance with Item 2a and 2b below, unless justification for continued operation has been provided to the NRC.

Response: See Iowa Electric's previously transmitted response, LDR-81-94 dated March 13, 1981.

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 la above.

b. Perform an operability test on a r?presentative sample of inaccessible snubbers as described in Item ib above.

c. Snubbers which have been examined and tested in a manner comparable to Items 2a and 2b above within the last six

. months may be exempted.

d. If any tailures are identified in. Items 2a or 2b above, take corrective action to evaluate the effect of the failure on system operability pursuant to the facility technical specifications for resuming operation.

Response: Refer to Part I of the response to Item 4. -

Item 3: Profide a schedule for an inspection program covering mechanical snubbers produced by other manufacturers. . As a minimum, this inspection program shall:

a. Include all snubbers installed on safety-related systems-

5. 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 2

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e. Be completed prior to the completion of.the.next refueling  !

outage. Plants wnich 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: Refer to Part II of the response to Item 4 Item 4: Submit a report of the results of the inspectior.s,-testing and evaluation requested in Item 1 to NRC within 45 days of 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 Ite.n 3 shall be-submitted within 60 days of the issuance date of this Bulletin. The results of the inspections performed -for Item 3 shall be' submitted within 60 days after tne completion of the inspection.

The reports shall contain the following:

a. A description of-the visual examinations and tests performed.

b. Number of snubbers examined and tested. Grouping by macafacturer name, 'model number, and size is ao eptable.

c. Number of failures identified, manufacturer name, model number, size, mode of failure, cause of failure, corrective action, snubber location, effect of failure on plant and system safety, and justification for continuing er resuming operation.

d. The above -information shall also be provided for the snubbers

exempted by Items ic, 2c, and 3c above.

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Response: PART I At the DAEC, there are six (6) International Nuclear Safegards.

Corporation (INC) mechanical snubbers installed on safety-related systems.

a. Visual examination and tests performed:

1) Tne visual inspection of all INC snubbers consisted of the fol lowing:

1) Verification of snubber installation per design document

11) Inspection of snubber welds iii) Inspection of structural attachments

, iv) Inspection of snubber for evidence of external corrosion v) Inspection of snubber's spherical bushings for disengagement

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2) The manual testing of all INC snubbers consisted of the following: ,

I i) Confirmation that the spherical bushings rotated without l excessive force (i.e., could be rotated by hand).

ii) Stroking the snubbers from the fully retracted to the fully extended positions a minimum of three cycles to confirm their freedom of movement over the entire range of travel.

3) The operability testirg of the INC snubbers was performed par Wyle Laboratories' Test Procedure No. 545-5479-CP, Revision 0, dated March 23, 1981, titled " Test Procedure for Operability Test on International Nuclearsafeguard Corporation Mechanical Snubbers." This test measured the breakaway friction and activation force of each snubber.

Acceptance criteria for the operability test was based on the design specification for the INC snubbers (" Design Specification for Mr.chanical Shock and Vibration Arrestor (MSVA)", Engineering Document Control Number 128, Revision 1, dated September 1,1976).

b. Snubber identification and data:

INC MECHANICAL SNUBBERS CATEGORIZED BY MANUFACTURER, MODEL AND SIZE MANUFACTURER QUANTITY OF SNUBBERS MODEL AND SIZE INC (international 6 MSVA-1 Nuclearsafeguard Corporation) 4 Note: The above table includes all INC snubbers at the DAEC.

c. Inspection results:

See Table 1.

d. There were no snubbers exempted from testing per Bulletin Item 2c.

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TA8tf I SLM MRY OF INC SNUBBER DEFICIENCIES * ,

Snubber Manufacturer Model Mode of Cause of Corrective Ef fect of Deficiency Justification for Location Jize Deficiency Deficiency Action on Resuming Operation Plant and System Safety t-- -

Snubber is INC MSVA-1 The snubber's Since the snubber The deficient lowa E*ectric, with the The deficient IC located in design specification at the time of itC snubber has assistance of the snubter has toen re-the i. eam specifles a breakaway original Instal- been replaced Bechtel Power Corporat- placed with an in-tunnel on the friction during either lation was per its with a spare lori, has performed a spected Pacific MSIV leakage retraction or extens- design specificat- PSA-1 snubber. stress reevaluation to Sci ent if ic PSA-5 control line lon of not greater lon, it in Hefore instal- determine if the l E which, based on.

between than 15 of the believed that tha l lation, the snubtwr deficiency load capacity and

,enual snubber's rated f ad. excessive break- spare PSA-1 resulted in. the MSIV desigr. condit ions, valves V-84-17 T% verahility .ast away friction is mechanical Leakage Control Line is an acmptable and V-84-18 performed on the due to an accumu- snubber was in- having been over- replacement snubber.found that lative usage spected as stressed. Based on the component. In its tx eakaway friction degrading of the described in results of this re- addition, a stress was 1.5% of rated load snubber's Internal response to evaluation, it is reevaluation has during retraction and mechanism. Bulletin item 4, determined that the resulted in a deter-25 of rated load , Part 11, Section MSIV Leakage Control minat.on that the during nxtension. a of this report Line had not been over- plant safety and and was found to stressed and that the system safety-tw acceptable. plant safety and system function had not safety function had not been compromised by been compromised alaring operating with the plant operation. det Iclent snubber.

• Of the six (6) INC snubbers at thu DAEC, there was a total of one (1) deficlunt snubter.

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Response: PART II ,

At the DAEC there are 149 Pacific Scientific (PSA) mechanical snubbers installed on safety-related systems. Included in this

. total-are 17 new PSA snubbers installed during the DAEC's 1981 refueline outage (March-May 1981) tnat were exempt from visual examination and manual testing per Bulletin Item 3c.

a. Visual examination and tests performed:

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1) The' visual inspection or all PSA snubbers consisted of the following:

i) Verification of snubber installation per design document

11) Inspection of snubber welds iii) Inspection of snubber transition tube bolts to. confirm that they were secure iv) Inspection of structural attachments v) Inspection of snubber for any evidence of external corrosian vi) Inspection of snubber's spherical bushings for disengagement

2) The manual testing of all PSA snubbers consisted of the following:

1) Confirmation that the spherical bushings rotated without excessive force (i.e., could be rotated by hand). '

ii) Stroking the snubbers from the fully retracted to the fully extended positions a minimum of three cycles to confirm their freedom of movement oveY the entire range of travel.

b. Snubber identification and data:

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PACIFIC SCIENTIFIC SNUBBERS

. CATEGORIZED BY MANUFACTURER, MODEL AND SIZE i MANUFACTURER QUANTITY OF SNUBBERS- MODEL AND SIZE Pacific Scientific 58 PSA-1 Pacific Scientific 26 PSA-3 Pacific Scientific 23 PSA-10 I Pacific Scientific 23 PSA-35 Pacific Scientific 2 PSA-100 1

NOTE: the 132 Pacific Scientific snubbers listed above are all the Pacific ,

4 Scientific snubbers at the DAEC applicable to Bulletin Items 3a and 3b. )

c. Inspection result::

See Table 2.

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C-TABLE 2 (SHEET I) .

SUfemRY OF PSA SNUBBER DEFICIENCIES

• Snubter Manufacturer Model Mode of Cause of Corrective Ef fect of Deficiency Justification for I 1.ocation Size Deficiency Deficiency Action on a wuming Operation

, Plant and System Safety Snut,ber Pacific PSA-3 For the annual test The deficient The deficient lowa Electric, with the The deficient PSA location iden- Scientific the snubber was found snubber is being snubber was assistance of the snubber has been re-tification is to have impaired sent to Pacific replaced with a Bechtel Power Corporat- placed as detalled DCA-6-SS-50 freedom of movement Scientific for an spare Pacific lon, has performed a Ir. the 'Correctlvo Snubber is in (i.e., snubber re- evaluetion to Scientific stress reevaluation to Act ion" coluen of the drywell on quired excessive detesmine the snubber of the determine if the saubber this table. In the Reactor force to stroke), cause of the same size. deficiency resulted in addition a stress 9 Water Cleanup deficiency as well Before Instal- the involved piping reevaluation has

! System as refurbishment. lata (.e. the system having been over- res ulted in a deter-i The results of spare Pacific stressed. Based on the mination that 1%

this evaluation Sci ent 1;!c results of this re- plant saf ety and Snubber Pacific PSA-l will be trans- snubber was evaluation, it is system safety location Iden- Scientific mitted when they. Inspected as determined that the function had not tification is become available. described in piping of the involved been compromised by DBA->SS-31.

• response to system has not been operating with the Snubber is in Bulletin item 4, overstressed and that deficient snubber.

the drywell on Part il, Coction the plant safety and the RH System a of this report system safety function and was found had not been compromised acceptable. during plant operation.

Snubber Pac 1fIc PSA-I location Iden- Scientific tification is DBA *>-SS-38.

Snubber is in the drywell on the RHR System i

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For cantinuation of this table, please turn to the following page.

TABLE 2 (SHEET 2) i SL20MRY OF PSA SNUBBER [*FICIENCIES*

e Snubber Manufacturer Modei Mode of Cause of Correct I ve Effect of DefIclency JustIfIcatlon tcr Location Size DefIclency DefIclency Action on Resuming Operatsan Plant and System Safety y Snubber Pacific PSA-1 Same as Table 2 Same as Table 2 Same as Table 2 Same as Table 2 Same as Table 2 location Iden- Scientific (Sheet I) (Sheet 1) (Sheet 1) (Sheet I) (Sheet l) tification is a 17 as shown ou piping Isometric FSK-4165-b.

Snubber is in the drywell on a vent line

• for loop B of .

the Recircu-lation Systw.

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for ccatinuation of this table, please turn to the following page.

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, . 4 TABLE 2 (SHEET 3)

SUMMARY

OF PSA 584JtWER DEFICIENCIES 1 -

Snubber Manufacturer Model Mode of Cause of Corrective E f fect of Def iciency Justification for' Location Size DetIclency DetIclency Action on Resuming Operation -

Plant and System Safety Snubber Pacific PSA-10 One or both bushings A bulld-up of dis

• The f rozen Iowa Electric, with the The deficient PSA location iden- Scientific were found to be and grime on the bushing (s) was/ assistance of the snubber has boon re-tification is frozen (i.e., could bushing (s) were returned to Bechtel Power Corporat- turned to its SSD-1-MS. not be rotated by impaired the free- an operational lon, has performM a design condition by Snubber is in NOTE hand). Footnotes dom of rotation. condition by stress reevaluation to methods detailed in the dryvull on i Indicete which lubrication and determine if the snubber the 'Correctl ve main steam bushings were frozen. cleaning. deficioney resulted in Action" coluan of line "D." the involved piping this table. - in systen having been over- addition, a stress Snubber Pacific PSA-10 I stressed. Based on the reevaluation has location IJen- Scientific results of this re- resulted in a tification is evaluation, it is deter- determination that

, $$A.g.MS, mined that the piping the plant safety and Snubber is in NOTE of the involved system system safety .

the drywell on 2 has not been over- f unct ion had not main steam stressed and that the been compromised by line "A." plant safety and system operating with the safety function had not def icient snubber.

Snubber Pacific PSA-10. twwi compromised during location idea- Scientific . plant operation, tification is SSA-2-MS.

Snubber l' In NOTE the drywell on 2 main steam l i ne "A."

Snubber Pac 1fIc PSA-10 location iden- Scientific i filication is DLA-5-SS-10 Snubber is in NOTE the drywell on ,3 l the RHH system 4

For continuation of this table, please turn to the following page.

TABLE 2 (SHEET 4)

Supe 4ARy 0F PSA S8eJBEER DEFICIENCIESS a

5:ubber Manufacturer Model Mode of Cause of Corrective Et f act cf Deficiency Justification for

• Location Size Deficiency Deficiency Action on Resusing Operation 3 Plant and System Safety Snubber" PactiIc PSA-10 location Idea- Scientific tification is NOTE Same as Table 2 Same as Table 2 Same as Table 2 Same as Table 2 Same as Table 2

. GOC-10-SS-24 3 Sr.ubber is in (Sheet 3) (Sheet 3) (Sheet 3) (St.eet 3) (Sheet 3) the drywell on Safety Hellet Line 10 d

Snubber Pacific PSA-1 Transition tube bolts Oversight at time TLs diameter of The deficiency had no The transition tube location iden- Scientific were not secured with of installation. safety wire ef fect on plant safety bolts have boon safety-tificotlon is correct diameter specified in the or system safety wired with the diameter Gott- 13-SS- 16. safety wire as Pacific function since the safety wire specified Snubber !s in specified in the Scientific in- transition tube bolts, by the Pacific Scienti-an accessible Pacific Scientific stallation In- while they were secured flC Installation In-area of the Insta*lation structions was with the smallar s truct ions . This will reactor Instructions. Installed. diameter saf ety wire, Insure that the trans-building on were found to be ition tube bolts will the core spray torqued tight. remain torqued to the system. torque value reluired by Pac 1fIc SclentIfIc.

T heref ore, it is deter-sined that the Inst al-4 latsom deficiency had not compromised plant safety or the saf ety f unction of the core spray system.

1. Of the 132 Pacific Scientific snubbers at the DAEC that ere applicable to Bulletin items 3a and 3b there was a total of ten (10) deficient snubbers.

• 40TES:

1 Doth the snubber s f orward bushing (defined as that bushing pinned to the snubber's pipe clamp) and rear bushing (defined as that bushing e

pinned to the snubber's clevis attachment) were found to be frozen.

2 The snubber e s forward bushing (defined as that bushing pinned to the snubber's pipe clamp) was found to be froJ an.

3 The snubber's rear bushing (defined as that bushing pinned to the snubber's clovis attachment) was found to be frozen.

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d. See Table below.

SNUBBERS EXEMPTED FROM SURVEILLANCE CATEGORIZED BY MANUFACTURER, MODEL & SIZE MANUFACTURER QUANTITY OF SNUBBERS MODEL AND SIZE Pacific Scientific 14 PSA-10 Pacific Scientific 3 PSA-35 NOTE: Each of the 17 Pacific Scientific mechanical snubbers listed above underwent a functional test by the manufacturer (ie., Pacific Scientific) prior to delivery to Iowa Electric. Certified test data sheets documenting the results of each functional test were delivered to Iowa Electric with the snuobers. These snubbers were installed during the OAEC's 1981 refueling outage (March-May, 1981). Uf the 17 Pacific Scientific mechanical snubbers, there were no deficient snubbers.

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