ML20141N301
| ML20141N301 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities, 05000000 |
| Issue date: | 06/23/1972 |
| From: | James Keppler US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Brunner E, Robert Carlson, Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20141N278 | List: |
| References | |
| FOIA-85-782 NUDOCS 8603060113 | |
| Download: ML20141N301 (1) | |
Text
DIRECTORATE OF REG
.IORY OPERATIONS Memo Rout? Slip h
2A d
RT&OB:AR:80 R. T. Carlson V.
Region I X
RE: QUAD CITIES 2 - HANGER FAILURES ON E. 24. Hovard TORUS SUCTION HEADER - COMMONWEALTH Rettion I X
EDISON COMPANY'S REPORT TO LICENSING E. J. Brunner DATED JUNE 7,1972 Recion I X
F. J. Long Enclosed for information is a copy of the Region II X
subject report.
As you are aware, an RO W. C. Seidle
__ Bulletin (72-4) was sent to all currently Region II X
operating BWR's (post Oyster Creek) as a 1;. C. !!oseley result of this problem. Additional informa-Renion II X
tion on this problem will be forwarded to G. Fiorelli you when available.
Rerion III X
D.ii. Hunnicutt Enclostjre:
Region III X
As Stated W. E. Vetter Region III -
~ X' cc:
J. B. Henderson J. W. Flora G. C. Gower Region IV X
G. S. Spencer Region V X
- s JUN 2 31972 Old y(
FROM:
J. d. Keppler DATE:
6/20/72 8603060113 860114 PDR FOIA
/
NORROW85-782 PDR
Commonwealth <dison Company Q U A D.C I TI E S NUCLEAR PoWE R STATION o
Aar. n e r m Po$T offlCE toX 214
- CotDoVA. ittltvo45 41242 FAP-72-107 l,
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June 7,1972 t../* ~
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Mr. E. J. Bloch Acting Director, Directorate of Licensing Cf I./j,,le. y[.', '
U. S. Atomic Energy Commission 4
1..dM Washington, D. C. 20545
Dear Mr. Bloch:
.t Ref: Quad-Cities Nuclear Power Station - Unit 2, DPR-30 Appendix A - Section I.A.4, Section 6.6.B.2 and Section 6.6.B.3 The purpose of this letter is to inform you of the details regarding the failure of four hanger bolts for the torus suction header at Quad-Citics Unit 2.
This incident occurred on May 29, 1972 at 1:30 a.m.
Description of Failure During Phase IV startup testir.g on Unit 2 at' Quad-Cities Nuc1 car Power Station with the reactor operating at 28 per cent thermal power, four torus suction header hanger bolts were found to have failed. The failure was discovered at 1: 30 a.m. on May 29, 1972. The four respective hangers supported approximately a 90 segment of the suction header. The maximum downward displacement of the suction header was approximately 6 inches. Shutdown of the reactor was started immediately; all rods were inserted by 4:00 a.m.
on the 29th, immediate Actions Station Maintenance personnel were called in immediately.
A temporary rigging was constructed to support the ring headers at its displaced position. This rigging prevented any further dis-placcmont and prevented further stresses on the structural members.
Visual inspection of the suppression chamber and suction header was completed indicating no deformation.
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C Mr. E. J. Bicch June 7,1972 Initial Investination initial investigation of the four failed hanger bolts revealed that the bolt guide hoics on the torus and header brackets had been
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torch cut to arbitrary sizes to allow the bolts to pass through, rather than cleanly drilled to the size specified on the construction
, drawing. Also, i t was found that the respective bolt holes in the hanger strap pieces appeared to have been punched instead of drilled.
The punching left a sharp edge and some holes were enlarged with a torch to achicyc fit up.
The torch cut hangers caused stress riscrs to. develop in the support bolts.
In addition, it was found that fully threaded bolts had been used, whereas partially threaded bolts should have been used.
The failed specimens, and the arcas subjected to maximum stresses weretvisually inspected b,y; an Edison metalurgist, representatives of Chicago Orldge & Iron Company, and Sargent & Lundy Engineers. All inspections found no apparent yeilding of,the suppression chamber shell or of the suction header and its nozzles. Chicago Bridge & Iron also conducted an analytical stress analysis on the suction header.
Approximate maximum strespes were calculated for the header, nozzles, and torus shcIl to nozzle insert plate junction. Chicago Bridge &
Iron's conclusion based on the analytical calculations, visual excmin-ations and the assumed satisfactory results of proposed non-destructive testing of the wolds receiving maximum stress, was that the integrity of the vessel had not been jeopardized. The proposed non-destructive testing performed was liquid penetrant examination of the welds joining.
the neck to insert and insert to torus shcIl for suppression chamber penetrations X-204A and G.
The results of these examinations were satisfactory.
Additionally, pieces forming one complete bolt were analyzed by the Charles C. K owin Company for Sergent & Lundy. The bolts were within specified chemical and hardness limits. The failure mode for the bolts was confirmed to be shearing. There was no evidence ef fatique in the samples examined.
Reports of the above mentioned analyses are attached hereto.
Interim Fix As an interim fix for the failed hangers, the corrective action was to replace all of the original 2-1/2 inch wide by 1/2 inch thick hanger straps with a 3 inch wide by 1/2 inch thick strap, and replace all original 3/4 inch cap screws for the hangers with bolts 1 inch diameter machine bolts. The original cap screws were ASTH-A-307 specification and the new boirs are A-325. The-l inch diameter threaded
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Mr. E. J. Birch June 7, 1972 bolts now installed are to be replaced with a 1-inch diameter bolt that has a non-threaded bearing surface. The new bolt hanger hoics were in-line drilled. This fix was approved as adequate by Chicago Bridge & Iron. This work was completed and reviewed by,the Quad-Citics Station Review Board and the Edison Nuclear Review Board and approval was authorized to return the unit to service. The results of the investigation and repairs were discussed with AEC Region ill Compliance representative, Mr. E. Jordan prior to plant startup.
The Unit was returned to service at 4:21 a.m. on June 4,1972.
Continood investloations Continued investigations and tests are planned for the torus and suction header. General Electric is planning to install approxi-mately 20 vibration detecting sensors at various locations on the suppression chamber and suction header. They propose a series of tests to monitor containment system vibration and torus movement.
The t'ests will include simultancous operation of all electromatic relief valves, and operation of the vorious ECCS pumos using the suppression chamber. During the tests vibration specia, lists will observe the performance and interpret the results. The results of the analysis performed from the date obtained on this test will be forwarded to you on a timely basis. These tests are tentatively scheduled for the last week of June, 1972, and the test results should be available by July 21, 1972 Based on the results of these investigations, any proposed modifications of the existing suppression chamoer design will be reviewed and installed as required.
The changes made on Unit.2 are also being done on Unit 1 Very truly yours, COMMONUEALTH EDISON COMPANY Quad-Citics Nup/lear Power Station
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Superintendent FAP: REQ /zm attachments:
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Letter - S & L to General Electric - June 2,1972 0
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Subject:
Qusf.. Cities Mntion. - Unite i c.nd 2 O c : a rs 1 ~.:1cctric i;:r:p:.n:s in:'
Cornw. malth TAiscn:CO2p rayI I.
Tutit 2 enite i
Ring Ttender Suz, ort solts t
Mr. P.
2,ccaburr., 72oject Enra.3cr Ur:7D* 22. 31cotr1c CM.ps.c:!
0.uad-Citisc. ihtclear. Pot:cr S2mlon
!?. O. ?,cx 291 Cordova. Illis i 619?2 i
Dear :
- r. Lcocb
- :rg7 1Tc sent the pie.eca forning otra cc:aploto bW.t frco the hon.;e.vn on the Unit t?2 tcmo ring header to Charlos C. J':.cin Corspcny fo,*
ttnalysis.
Iso rce,v-aded tha'e cho / provida us with the folloili".3:
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1'b0; cit.::qh tho cpt.>cL:,cna 4
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Check i,r.rdnos c)
Deterrdnu chc...ist:rj d)
Show cold uor;t. of chcaring on one couplo b:/
obtad.4.o;; a pho:cnicro;;raph perpendicular to the fznctura curface.
I an enclocite.; thrce (3) cc?ien of the reg.ert receiv'ed from Charles C. ::cuin Ccr.pAny.
'lnic report concuinn all of the 3;r.Mr::.u-tion which uc raricosted.
Tha bolta e e det.crafhed to be nupplicd to A3T!I A-307 Speci:":. :.-
t tion titled " Lou C::r'oon Scubi Zntorna'ily and Internally 'i'hrer..ed d,
. Standard Fm;tentra.
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'Juna 2 ~1972 Genera.T Mecu-i.e cogpeny.
p::c,e y;;o-ASZ:~.*;-307 hndnosc rc..g:1remd;s for Orado ?, bolta cro 121 to 207 7>rinen or d9 to 9:j Hoar.1.f11 L All sec;;onta of the bolts testini fall Within thes.2 ;rr.n,pm.
The higher hardnecs of tho hccd ::cction.9 ~.'clievci to remnt: fron-the nethod of ncnufacture, nancl/
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Chc:nist:7 rce..Witd for.'lcade D 'ocl0s to /,SEI-A-307 in phosphorous 0.04 cr.:t em2;ur C,03. ::::.0:un per ccnt,.
Tha check nnedysis indi-cated all th;Na :;ng:rmta ^eatof. n:ce uithin the allo::cblo lir.its.
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The,G.oi:enicr: : c...cs tcun por_my..'..'.delar to the fracture surface illustrato cel; wod: and ::.atal f !.",;t in the c.hcar crea.
There is no evt.Gcnce c. C.tspm,e in the cgnplan e;;:crined.
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July 3, 1972 J. G. Keppler, Chief, Reactor Testing and Operations Branch Directorate of Regulatory Operations, Headquarters STATUS OF QUAD-CITIES TORUS HEADER HANGER REVIEW RO:III'has verified that Quad-Cities Unit 1 and 2 torus header vertical hangers have been replaced using 1 inch dieseter A 325 bolts with smooth shank in double shear supporting each ring header from twelve equally spaced 1/2 inch thick by 3 inch wide clevis bars. The hanger loads on each unit (12 hangers) were found to have been equalized by changing hanger bar length. The holes in the support web and hanger bars were found to have been drilled to provide parallel load bearing surfaces.
Dynamic testing on Unit 2 to measure the movement of the torus surface and ring header during actuation of relief valves, HPCI, RCIC, RHR and core spray systems was completed in June 1972. GE is currently analyzing the test results and plans to submit data to CB&I in the near future for their (C8&I) reanalysis of the torus header stresses based upon static loads plus dynanic loads and postulated seismic stresses.
A tabulation of hanger loads for each unit as found and as adjusted is listed on Attachment A.
D. M. Hunnicutt, Chief R0:III:EIJ Resctor Testing and Startup Branch Attschment:
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F As Fcund Adjusted As Feund Adjusted Unit 2 Positten Unit 1 Unit 1 Unit 2 Unit 2 Azimuth
- North 10,800 7.600 11,200 F 10,100 90 8,800 7,600 9,400 F 9,400 112 30' 4,700 5,100 13,000 7,400 157 30.'
East 15,200 8,000 700 8,300 180 7,900 6,700 11,600 7,200 202 30' 6,300 5,800 3,600 6,700 243 30' South 14,500 7,600 7,600
-7,600 270
'O 7,100 12,000 7,800 292 30' 2,700 7,600 22,300 7,600 337 30' West 4,000 2,600 700 8,500 0
16,800 7,400 13,200 F 8,900 22 30' 9,700 6,300 5,400 F 7,800 67 30' t
Hanger status of Units 1 and 2 as of June 19, 1972
- See CB&1 Drawing No. 217 F - Failed Hangers O
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ATTACHMENT A 1
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Commonwealth Edison Company ONE FIRST NATIONAL PLAZA
- CHICAGO. ILLINOIS Addrene Gene see r
POST OpplCE SOR 767
- CHIC A G O, I L L IN OI S 4 0 4 9 0 July 5, 1972 Mr. Boyce H. Grie'r Regional Director Directorate of Regulatory Operations, Region III U. S. Atomic Energy Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Grier:
This letter is bet g sent in response to your letter of June 22, 1972 requesting the results of our inspections of the Dresden and Quad-Cities torus suction headers.
QUAD-CITIES Inspections On May 29, 1972, the night of the Unit 2 incident where four hangers were found to have failed, an inspection of the Unit 1 suction header hangers was made.
hanger had its support bolt broken.This inspection revealed one Additionally, several others were found to be bent.
No deflection or other damage to the Unit 1 header was observed.
its discovery.,
.The broken bolt was replaced at the time of Corrective Action The same corrective action that whs taken on Unit 2 was also take'n on Unit 1.
All of the original 2h inch wide by } inch thick hanger straps were replaced with 3 inch wide.by } inch thick straps; also all original 3/4 inch fully threaded bolts for the hangers were replaced with 1 inch diameter bolts with a non-threaded bearing surface.
and the new bolts are A-325.The original bolts were ASTM-A-307 specification to prevent the nuts from working loose.All newly installed bolts were " staked" The bolt hanger holes were in-line drilled.
This corrective action has been approved by the Chicago Bridge & Iron Company, and was checked as completed on June 12, 1972.
The loading on each hanger was measured af ter the revised
' hangers were adjusted to improve load distribution 5
The hanger load distribution after adjustments is as follows:
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Mr. B. H. Orier July 5, 1972 Load - Lbs.
Hanger No.
Unit 1 Unit 2 1
2,600 7,800 2
7,600 10,300 i
3 7,100 9,400 lr 4
7,600 7,400 i.
5 5,800 8,300 i
6 6,700 7,200 t
7 8,000 6,700 8
5,100 7,600 9
7,600 7,800 10 7,600 7,800 4
11 6,300 8,500 10 7,400 8,900 j
On Unit 1, hanger No. 10 was assigned plant north with numbers decreasing in a clockwise direction.
On Unit 2, hanger l
No. 2 was assigned plant north with numbers increasing in a clock-wise direction.
The load distribution was discussed with Chicago Bridge & Iron and felt to be acceptable by them.
j Continued Investigations, General Electric Company conducted a s'eries of tests on the Unit 2 containment system during this current month.
Approxi-mately 20 displacement sensors were installed at various locations on the torus and suction header.
The_ tests included simultaneous I
operation of all electromatic relief valves, and operation of the I
various ECCS pumps using the suppression chamber.
The results of i
these tests are presently being analyzed, and if any further design j
modifications are required, we will keep you. informed.
i i
i DRESDEN I
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Preliminary Inspection j
On Jun'e 29 & 30, 1972, the torus suction header supports I'
j were visually inspected, without disassembly, to-assure that all components are in accordance with design, are in the proper position, and do not indicate damage.
Results of these inspections are as 4
follows:
f Unit 2.-
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. The hanger assemblies generally were found in good condi-
, tion with the following exceptions.
1)
Bay #5 vertical straps were found to have less ' bearing l
j material than design below the bolt shank.
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Mr. B. H. Grier July 5, 1972 2)
Bay #3 vertical straps had double holes drilled in a vertical plane with the bolt attached in the upper hole.
3)
Two sets of vertical straps were found to have been slightly bent, apparently to facilitate installation.
In addition, the seismic restraints at all positlons were examined and found to be extended beyond their normal range.
Unit 3 The hanger assemblies were fo' nd to be in good condition u
with the exception that no locking nuts were used on the bolts.
In Laddition, seismic restraints were found to be in the proper position in accordance with design.
Detailed Inspection All hanger assemblies were disassembled for closer inspec-tion on Unit 3 during a weekend outage.
All bolts, bolt holes, and support pieces were examined for proper design, position, and damage.
1)
All bolts were 3/4" x 2-3/4", as specified by ' esign.
Bolt d
clear shank length varied from 3/4" to 1".
consequently, some of the lead was carried on the threaded portion of the bolt.
One bolt of the total of 56 appeared deformed.
to be slightly 2)
Bolt holes - All bolt holes were inspected on straps and support plates.
Some holes were drilled and some were flame
- cut, Dimensional checks indicated approximately 13/16" diameter, as specified in the design.
The following exceptions were noted:
a)
Bay #1 and Bay #7 had double hulea drilled in a horizontal plane on the ring header support plate.
The holes were spaced between 3/4" to 1 " apart.
b)
Bay #2. had a double hole drilled in a vertical plane on the ring header support plate with the bolt passing through the lower hole.
The upper hole,was plugged.
,The plug was loose in the upper hole.
c)
Seven holes which were flame cut were slightly oversized and oval in shape.
While disassembling each ring header support, the hydraulic jack loadings were used to determine the vertical hanger support loads.
This. data was reported and found to be within allowable load
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Mr. B. H. Grier July 5, 1972 for the new bolts (A-325).
Two vertical hangers were found essentially unloaded.
After the above mentioned inspections were made and while the unit remained shut down, the following changes were made in accordance with the Chicago Bridge & Iron Company and Mechanical and Structural Eng*ineering Department recommendations.
1)
All vertical and horizontal support bolts were rep' laced with new, certified, hi h strength A-325 3/4" x 3 lg.
bolts with a l}" clear unthreaded) shank.
2)
All nuts were replaced with new, certified, double nuts of the same material.
3)
The two unloaded hangers were replaced with new i" x 3" A36 certified bar stock along with the new 3/4" x 3" 18 A-325 bolts, and dimensioned in order to increase the loading o'n these hangers.
The hanger load distribution after adjustment is as follows:
Bay No.
Load - lbs.
1 2,700 2
12,320 3
5,800 4
11,600 5
11,600 6
7 12,320 8
7 600 l
9 8,960 10 11,400 11 10,600 l
100 12 11, 13 41,200 14 15 6,300 16 5,800
- Design does not require a hanger in these bays and none are installed.
A similar disassembly and inspection will be performed on Unit 2,as soon as practical.
A seismic analysis is being per-formed by Chicago Bridge and Iron Company to determine whether the hanger disassembly and inspection can be safely made with Unit 2 at' power.
Bolt replacement and hanger adjustments will be made on Unit 2 as required.
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' Mr. B. H. Grier July 5, 1972 We are evaluating the ring header support plates which have double holes, and those straps which have oversized, flame cut holes, to determine whether corrections are required.
Seismic. restraints on Unit 2 will be readjusted to conform to design specifications.
All corrective actions are expected to be completed by July 15, 1972 if the safety evaluation shows that the detailed inspection can be done with the unit in service.
If an outige is required, the detailed inspection will be done on the firr,c 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> outage.
Very truly yours,
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A/q;<'
H. K. Hoyt Superintendent Production-Nuclear HKH:BRS:mak cc: Messrs. F.
A. Palmer W. P. Worden e
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June 2?,1972 Cor=ionwealth Edison Co:apany Docket No. St-? 17 ATTN: Mr. Eyron Leo, Jr.
50-249 Asciscant to the President 50- 25 '+
P. O. Box 767 SC-265-Chicago, Illinois 60650 Gentleraen:
As a result of the hanger failures experienced with the cracrgency core cooline. dystem succion header at your Quad-Cities 2 rotetor facility, the Directorate of Regulatory
- Operations has sient the encloced information Sulletin No. 7.)-1 to other operators of boiling water reactors.
It is requested that the inspections described in the encloaure be conducted at your Quad-Cities 1 and Dresden 7 and 3 facilities, and the result 4 of your inspections be provided to this oCfice.
If you have any questions concerning this matter, plea:.e let me kno.a.
Very truly yours.
Boyce 11. Grier Regional Director
Enclosure:
Bulletin No. 77-1 cc:
Dresden Station Superintendent Quad-Cities Station Superintendent bec: R0 Files Deputy Director, L DR Central Files Asst. Dir. for BUR's, L (P PDR Asst. Dir. fo r PR 's, L ( 3)
Local PDR Asst. Dir. for OR's, L (P Branch Chiefs, RO Asst. Dir. for Ens iron. Proj., L (3\\
Asst. Dir. for Procedures, RO R. F. Fraley, ACRS Asst. Dir. for I&E, RO NSIC Asst. Dir. for Plans & Prog., RS R. L. Shannon, DTIE Director, L r4 u-
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6-27-72 6-22-72 V 6-2-72 DATE>.
Forse 4EColle,Rev. 9-53) AECM 0240
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Date: June 22,1972 Directorate of Regulatory Operations Bulletin 72-1 FAI1ED HANGERS FOR EMERGENCY CORE COOLING SYSTEM SUCTION HEADER We re'cently received information from the Commonwealth Edison Company concerning a problem found during startup testing of the Quad-Cities 2 boiling water reactor which may relate to the design and long term performan e capability of the torus and the emergency core cooling suction he.ader at your facility. The information is as follows:
a.
Description of Circumstances During startup testing the licensee found that four of the pipe hangers which support the 24-inch diameter torus suction header had failed. The 24-inch suction header serves as the main source of water for the emergency core cooling systems. Water is supplied to the header from the torus through four 20-inch diameter pipes spaced 90 degrees apart. The header is supported by three equally spaced sets of vertical and horizontal hangers which are attached to support plates welded to the torus and which are located between each of the four 20-inch pipes which join the suction header to the torus. A total of 12 hangers support the 24-inch suction header.
The reactor was promptly shut down for investigation and repair following the discovery of the failed hangers.
Three of the four failed hangers were located within a 90 degree section of the header and resulted in a maximum sag in the header pipe of approximately six inches within that section. Four 3/4-inch diameter bolts (threaded their entire length), which secured pairs of shackles to the support plates welded to the torus and to the 24-inch diameter pipe, werc~ found to have failed in double shear.
The cause of the bolt failures has not as yet been determined; however, it is known that the suction header experienced vibration as a result of operational testing of the emergency core cooling system.
In addition, the bolt holes, which were formed by flame cutting and punching, were found to be irregularly shaped and poorly aligned.
Chicago Bridge and Iron Company, the contractor for the torus and suction header design and installation, has provided a revised design requiring use of 1-inch diameter high strength bolts with smooth unthreaded bearing surface, and appropriately increased the size of the shackles. The change is being implemented for all the. hangers.
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. Commonwealth Edison Company and Ceneral Electric Company plan to conduct additional investigation to determine the effect on the suction header and torus of routine plant operations and testing of the emergency core coolind systems.
^
We have also been informed that the Northern States Power Company's Monticello reactor found one bent suction header hanger bolt and is also currently replacing the hanger bolts with 1-inch diameter bolts.
b.
Action Requested of the Licensee It is requested that you conduct the following inspections for each at your facilities and provide this office with the results of your inspection.
1.
An inspection of the hangers, shackles and support plates for the torus suction header to assure that all components are in accordance with design, are in proper position, and do not indicate damage.
2.
Inspect each bolt used to attach the shackle and support plate of each hanger (1) for deformation, (2) to establish that bolts are of the specified design, (3) to establish that specified locking devices are installed and (4) that the bolt shank supporting the header weight from the support and shackle is not threaded in the bearing area.
If the results of your inspection indicate the existence of conditions similar to those described above, or if any problems have previously been experienced with failed hangers or bent hanger bolts at your facility, please include in your response a description of the problem and the corrective action taken or planned, if any, and the date of scheduled completion of any planned corrective action. This information should be provided to this office, in writing, within ten days of your receipt of this letter.
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July 27, 1972 CDP y
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D. J. Skovholt, Assistant Director for Operating Reactors, L (3)
COMMONWEALTH EDISON COMPANY (QUAD CITIES 2) - DOCKET NO. 50-265 TORUS SUCTION HEADER HANGER FAILURE The enclosed report from our consultant, Mr. R. A. Lofy, along with memoranda from our Technical Assistance Branch and Region III (Chicago)
Office, are forwarded for information. These enclosures relate to the special inspection that was conducted on June 6, 1972, concerning the failure of pipe hangers used for supporting the torus suction header at Quad Cities 2.
Preliminary information relating to this failure was discussed in the Directorate of Regulatory Operations Notification of an Incident or Occurrence, Blue Sheet No. 56, dated May 31, 1972, and RO Inquiry Report No. 50-265/72-07, dated May 31, 1972.
Based on the results of our inspection, we have concluded that the hanger failures resulted from static overloading of the hangers (due to unequal distribution of loads). We,have also concluded that this problem resulted from the failure to consider all of the static and dynamic loads in the design of the header support system. Appropriate corrective measures have been taken at both Quad Cities reactors to prevent recurrence.
In addition, a test program was implemented by the licensee and General Electric to measure movement of both the torus and header during operation of the primary system relief valves and ECCS systems and to monitor vibration to determine the dynamic loads on the suction header during operation. We were informed by the licensee that a report summarizing the results of these tests will be submitted to the regulatory staff on or around August 1,1972.
As you know, a Regulatory Operations Bulletin was distributed'to licensees of applicable BWR operating facilities on June 19, 1972, to alert these licensees of the failure experienced at Quad Cities and requested that a visual inspection of the hangers and supports be performed. Although documentation of the'licensecs' findings j
f rom these inspections has not been received by our Regional Offices, preliminary information indicates that no similar hanger failures have been experienced.
Following receipt and review of Commonwealth Edison's report of their testing at Quad Cities 2, we plan to issue,a Supplemental Bulletin to su w, - ' I m p,
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i D. J. Skovholt July 27, 1972 all applicable BWR facilities, both operating and under construction, identifying the cause of the failure and requesting followup action, as appropriate, to preclude similar failures. We will discuss our specific recommended course of action with you prior to implementation.
A vR. H. Engelken, Maistant D. rector for Inspection and Enfcreement Directorate,of Regulatory Operntio'r.s* '
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Enclosures:
i 1.
Parameter, Inc.. Report No.DC-98 1
2.
Memo, TAB, dtd 6/21/72 w/ attachment 3.
Memo, Region III, dtd 7/3/72 a
w/ attachment cc:
F. E. Krucsi, RO P. A. Morris, RO A. Giambusso, L J. M. Hendrie, L R. S. Boyd, L R. L. Tedesco, L D. L. Ziemann, L l
W. R. Butler, L J. F. Stolz, L i
R. A. Clark, L J. G. Keppler, R0 J. B. Henderson, RO i
C. W. Rainmuth, RO B. H. Grier, RO:III, j ;,,,,,
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