ML20137J548
| ML20137J548 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/12/1985 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-34232-TDS, DER-85-39, NUDOCS 8601230082 | |
| Download: ML20137J548 (6) | |
Text
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Arizona Nuclear Power Project P.O BOX 52034 e PHOENIX, ARIZONA 85072-20J4 ANPP-34232 -TDS/TPS-92.12 December 12, 1985 U. S. Nuclear Regulatory Commission Q'
Region V 1450 Maria Lane - Suite 210
-m Walnut Creek, CA 94596-5368 N'
3 92 13 0 p
O Attention:
Mr. D. F. Kirsch, Acting Director 3
G3 *@;
m Division of Reactor Safety and Projects M
w g
Subject:
Interim Report - DER 85-39 c.n A 50.55(c) Potentially Reportable Deficiency Relating To NSSS Pipe Stop Bolting Material File: 85-006-216; D.4.33.2
Reference:
Telephone Conversation between A. Hon and T. R. Bradish on November 8, 1985.
Telephone Conversation between R. C.
Sorenson and T. Siegfried on December 9, 1985.
Dear Sir:
The NRC was notified of a potentially reportable deficiency in the ref-erenced telephone conversation. At that time, it was estimated that a determination of reportability would be made within thirty (30) days.
(December 8, 1985).
Due to the extensive investigation and evaluation required, an Interim Report is attached.
It is now expected that this information will be finalized by January 6,1986, at which time a complete report will be submit.t ed.
Very truly ourg, O?._Lk._
M
{
E. E. Van Brunt, Jr.
Executive Vice President Project Director EEVB/TPS/ldf At tachmen t(s) cc:
See Page Two 8601230002 851212 PDR ADOCK 05000529 I
S PDR I \\
i LL:47
r Mr. D. F. Kirsch DER 85-39 Page Two cc:
Richard DeYoung, Director Office of Inspection and Enforcement U. S. Nucicar Regulatory Commission Washington, D. C.
20555 J. G. Haynes (4060)
D. B. Karner (4060)
W. E. Ide (4074)
D. B. Fasnacht (6330)
A. C. Rogers (4056)
L. A. Souza (6195)
T. D. Shriver (6085)
D. E. Fowler (6260)
C. N. Russo (6330)
J. R. Bynum (6125)
J. M. Allen (6130)
D. Canady (6345)
A. C. Gehr (4141)
G. A. Hierzer (6330)
W. G. Bingham (6330)
R. W. Welcher (Bechtel/Norwalk)
H. D. Foster (6330)
D. R. Hawkinson (6330)
R. P. Zimmerman (6241)
M. L. Clyde (6079)
B. T. Parker (6345)
J. Provasoli (4057)
D. N. Stover (4082)
J. D. Houchen (6291)
J. E. Kirby (6501)
Records Center Institute of Nuclear Power Operations 1100 circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339
INTERIM REPORT - DER 85-39 POTENTIAL REPORTABLE DEFICIENCY ARIZONA NUCLEAR POWER PROJECT PVNGS UNIT 2, 3 I.
Potential Problem While tensioning NSSS pipe whip restraints in Unit 2, it was determined that some bolts were soft. Further investigation revealed that the bolts for the pipe whip restraints had been proc ired from Ametek-Straza. A total of 61 of 123 - 2k 8UN 2A x 14" studs in Unt: 2 and 3 did not meet the hard-ness requirements for ASTM AS40 GR B23 Class II materials. Twenty-nine of 64 studs installed in Unit 2 had hardness values less than the required minimum value. A total of 32 studs not yet installed, but destined for Unit 3, had hardness values not meeting the ASTM requirements. Thirty of the 32 failing bolts had hardness values less than that required and two had hardness values exceeding the maximum 388 Brinell Hardness Range.
II.
Approach To and Status of Proposed Resolution Bechtel Engineering has evaluated for Units 1 and 2 and is currently evaluating for Unit 3, the installation of all preload anchor bolts and studs for the NSSS pipe stops, reactor vessels, steam generators reac-tor coolant pumps, safety injection tanks and pressurizers.
The engineering evaluation of the NSSS pipe stops in Unit 1 identified two problems:
1.
The method used for the initial installation of the studs resulted in an inadequate preload being applied to the studs.
2.
Studs supplied by Ametek-Straza do not meet the specified ASTM A540 material property requirements. Material strength is lower than required. Note that these studs were not supplied under ASME specifications.
The root cause of the installation problem is attributed to using elongation as a measurement of preload combined with the movement of the reference surfaces during load application.
The root cause of the material problem is the inadequate heat' treatment of the stud material by the supplier.
The inadequate preload of the anchor bolts and studs of the Unit I NSSS pipe stops is addressed and resolved in the EER 85-EC-203 interim dis-positions which specified the methods to achieve.the proper preloads.
Prior to the completion of the work to properly preload the bolts and studs, the NRC exempted the need for the stops. Sufficient pre 1.oad exists for dead, live, and seismic loads.
The installation of the Unit 2 and 3 NSSS pipe stops will also be
~
adequate for dead, live, and seismic loads.
The results of the stud material review for the pipe stops are:
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,e Interim Report - DER 85-39 Page Two Initial hardness tests using the Equotip tester resulted in identifying:
(Test Results Only) a) Thirty-five of 64 2-k" diameter studs in stops A & B were unacceptable in Unit 1.
b) Thirty of 64 2-\\" diameter studs in stops A & B were unacceptable in Unit 2.
c) Twanty-one of 59 2-%" diameter studs for stops A & B were unacceptable in the warehouse, but destined for Unit 3.
d) Fifty-five out of 100 various diameter studs for other Unit 3 stops in the warehouse were tested and found unacceptable.
e) Twenty-nine unacceptable studs, based on hardness tests, were further tested in a lab to verify compliance with ASTM AS40 Grade B23 Class II.
Twenty were not in com-pliance. Nine were acceptable.
rhe lab results from testing studs have confirmed the inadequate heat treatment of the studs.
All thirty-five deficient studs in Unit 1 A & B stops were replaced.
During the retensioning of the Unit 1 studs, four replacement studs obtained from the warehouse yielded and were replaced.
Additional studs have failed on other stops.
Studs have been replaced, if they fail to take the preload.
The engineering evaluation of tae installation documentation for the reac-tor vessels, steam generators, reactor coolant pumps, safety injection tanks, and pressurizers has revealed that a majority of the anchor bolts /
studs were preloaded to a value less than specified.
Engineering has determined the existing preloads for the above items for Units 1 and 2.
Per Bechtel's and Combustion Engineering's evaluation and concurrence, the NSSS supports and anchor bolts for Unit 1 and for the completed work in Unit 2 have sufficient preload to meet design re-requirements.
Transportability of Material A review for ASTM AS40 bolting material of Purchase Orders 01-CM-125A and 13-CM-125, which supplied material for the NSSS support anchor bolts, revealed that only 88 anchor bolts for NSSS supports were manufactured by Southern-Bolt.
Sixteen of these 88 ASTM AS40 bolts were used as anchor
Interim Report - DER 85-39 Page Three bolts for the pressurizer and 72 were used as anchor bolts for 'the safety injection tanks.
It is not known in which unit the bol't's were used, however, the review of the installation data from the CIP's for the safety injection tanks and pressurizers did not reveal 4:..y evidence of material problems. All high strength ASTM A540 bolts that are speci-fied on Bechtel engineering drawings and all ASTM AS40 studs in the pipe stops are preloaded. The preload is greater than the design loads that the bolts will be subjected to during the plant life. Therefore, if the bolts are able to resist the applied preload, they have in effect been' load tested and are acceptable. Note that the shear is resisted by J
friction in the connection and that preload in the bolts provides' suf-ficient clampiag force to develop this friction.
]
In reviewing other AS40 material application for NSSS supports, one, steam generator. support anchor appeared slightly abnormal.
The nut for tha A540 forging A anchor bolt for Steam Generator No.1 in Unit 1 could not be threaded when the bolt was elongated. It was decided to shim the nut such that the bolt had the required elongation and therefore, the required pre-load. The cause of the threading problem was not determined at the time of installation, however, it was known at the time that some of the anchor bolts had flattened threads. This could have caused the problem. For the purposes of this evaluation, it was assumed that the bolt may have yielded.
Due to the reduction in final preload required, this bolt is not needed to resist the forces applied in the forging and would be acceptable with no pre-load.
In reality the bolt is supplying the preload at which it was anchored.
Transportability of Installation Bechtel Construction reviewed the procedure utilized during the initial bolt tensioning to determine if any problems reported are transportable to other installations on the project. The review indicates that the problem is lim-ited to those bolt tensioning applications made using the Pilgrim hydraulic stud tensioner for bolt elongation and la not transportable te other instal-lations. The basis for this conclusion is as follows:
- 1) the reported problem addresses suspect bolt preloads resulting from the use of a Pilgrim hydraulic stud tensioner for boit elongation. The use of these methods is limited to the NSSS component supports and pipe stops.
\\
- 2) Bolt tensioning, using stud tensioner supplied by Combustion Engineering or General Electric, was performed using internal mechanical extensometers to verify bolt elongation rather than external dial indicators as was used on the NSSS component sup-ports and pipe stops.
- 3) The bolt tensioning methods used in conjunction with the Pilgrim hydraulic stud tensioner and bolt elongation verification utiliz-C ing dial indicators are summarized on a discrete set of Special i
Construction Inspection Plans.
These SCIP's were all prepared during the same time frame and consistent areas of concern have been noted throughout the SCIP's.
These SCIP's and the methods described are unique on the project.
s Interim Report 39 Page Four Nonconformance Reports CC-5311 and CC-5312 have been written to address deficiencies for ASTM AS40 bolts and studs for Specification 13-CM-125B and 13-CM-125, respectively.
Ametek-Straza has been notified of the identified deficiencies. Eechtel Engineering is continuing to study the material, installation, and docu-mentation problems to determine reportability and technical justification for corrective action.
Ill. Projected Completion of Corrective Action and Submittal of the Final Report The complete evaluation and final report are forecasted to be completed by
- 4 January 6, 1986.
m 4