ML20024F288
| ML20024F288 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 09/02/1983 |
| From: | Kanga B GENERAL PUBLIC UTILITIES CORP. |
| To: | Snyder B Office of Nuclear Reactor Regulation |
| References | |
| 4410-83-L-0206, 4410-83-L-206, NUDOCS 8309090221 | |
| Download: ML20024F288 (6) | |
Text
r a
GPU Nuclear Corporation U Nuclear m'geSB 480 Middletown. Pennsylvania 17057 717 944-7621 TELEX 84-2386 Writer"s Direct Dial Number:
September 2, 1983 4410-83-L-0206 TMI Program Office Attn:
Dr. D, J. Snyder Program Director US Nuclear Regulatory Commission Washington, DC 20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
Operating License No. DPR-73 Docket No. 50-320 Polar Crane Load Test Assembly Evaluation Attached for your review and approval is the Polar Crane Load Test Assembly Evaluation. This submittal constitutes the response to Question 10 of Dr. B. J. Snyder's letter to Mr. B. K. Kanga dated July 18, 1983. GPUNC's response to the remainder of the questions was provided in GPUNC letter 4410-83-L-0175 from Mr. B. K. Kanga to Dr. B. J. Snyder dated August 16, 1983.
If you have any questions or desire further information, please contact Mr. J. J. Byrne of my staff.
Sincerely, B. K. Kanga Director, TMI-2 BKK/RBS/jep Attachment CC:
Mr. L. H. Barrett, Deputy Program Director - TMI Program Of fice SIS 830909022i O
GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation
o PO.AR LRANE LOAD TEST ASSENBLY EVALUATION The polar crane load test assembly has been recently re-evaluated for the pumose of confiming the fidelity between the as-oesigned ard as-built conditions.
The governing design documents are drawing 2-LDP-D01 Rev. 2 "Heao Lif t Load Test Assembly; Plans, Sections & Details" and Specifications 13587-2-C-371
" Furnishing Miscellaneous Metal" and 1M87-2-L-372 " Erecting Miscellaneous Meta l".
At issue was primarily the welding of the lifting lugs onto the frame members and subsequent in$ection of the welds. Accordingly, a thorough and detailed examination was conducted with special e@hasis on the physical oimensions and characteristics of the lifting lug welos.
The following paragraphs state specific issues of concern relative to this examination and provide msolutions to the same:
ISSUE 1 The welding procedure and welders were qualified per the ASE Boiler and Pressure Vessel Code,Section IX, in'11eu of MS Dl.1 as specified in the design documents.
RESO.UTION 1 Although the welders and welding procedure were qualified to ASE Section IX in lieu of MS Dl.1, paragraph 1.1.1 of MS Dl.1 allows the use of complementary codes or specifications for both design ano construction of steel structures. The application of ASME Section IX as invokeo by GRJN welding proceduIe WPS-lll for the load test frame is an acceptable alternate to MS Dl.1.
ISSUE 2 l
The welding procedure used was qualified for plate thicknesses up to 1.728".
RLSQ_UTION 2 This issue is being resolved by the implementation of a revised Proceoure QJalification Record (PQl) which will extend the qualification range of the appropriate procedure (WPS-111) for groove and butt welds to thicknesses up to and including 8".
ISSUE 3 The welds were insected to AWS Dl.1-79, Article 8.15, instead of the requirements in note 6 on drawing 2-LOP-1301.
RESO_UTION 3 Welds in@ected to AWS Dl.1-79 are acceptable. The 197!v edition is more stringent for undercut limitations than the later 1982 edition.
ISSUE 4 The welders who actually welded the lifting lugs to the main frame members were administrative 1y qualified for welding thicknesses up to and including 0.79'.
RES0_UTION 4 The mere fact that the welders were not acministratively qualified for the actual plate thickness welced does not mean that they were incapable of producing an acceptable weld. The subject welders weit seasoned and experienced craftsman who had previously proven their skills by qualification test of actual weld samples (colpons). Further, these welders are in the process of extending their aoministrative qualification to an unlimited thickness range in accorcance with ASE Section IX.
ISSUE 5 A new stess analysis should be conducted to verify the adequacy of the welds assuming that only 0.75" of the weld metal is effective, ie.,
taking no credit for weld metal thickness above that for which the welders were administrative 1y qualified.
RESU.UTION 5 A stess analysis has been performed on the lifting lug welds based on only 3/4" of weld being effective. A summary of the design stresses (based on terr = 3/4") and safety factors for the lifting lug welos is presented below. The stresses of the welds in question are within AISL allowables, even if crecit is taken for only the weld thickness up to the qualification limit of the welders. Any additional welo material serves to strengthen the joint and increase the margin to the allowable stresses.
2
1 Stress Summary with Factors of Safety for the Polar Lrane Load Frame Lug Welos (1),(2)
(3)
(6)
(4)
(5)
(5)
Liftirg Lug Type of Actual Allowable Yield F.S. t o Ultimate F.S. to Welds Stress 5 tress Stress Stress Yield Stress Ultimate ksi ksi ksi ksi detail 1 Tension 12.)
21.0 60 4.9 72 5.9 detail 2 Tension 11.8 21.0 60 5.1 72 6.1 detail 3 Tension 11.5 21.0 60 5.2 72 6.)
(1)
The polar crane load test assembly lifting lugs and weld details (from crawirg 2-UJP-1)Ql, Rev. 2).
(2)
The welds in this stress summary are based on 3/4" - the maximum weld size considered effective, due to welder qualification.
(3)
The lug welds are in tension only.
(4)
Based on the AISL Manual of Steel Lonstruction - 8th Edition (5)
Based on " Design of Welded Structures" - Blodgett (6)
Actual stresses are based on the design test load of 220 tons with a 25% increase for impact, and 3/4" of effective weld.
r ISSUE 6 The non-oestructive examination (NDE) performed on the subject we3dment should be reviewed for adequacy and completeness.
RESCLUTION 6 The quality control plant inspection report for the load test assemtely has been reviewed and the results found acceptable.
In fact, a more rigorous examination was conducteo than calleo for in the design documents in that a magnetic particle test (MT) was conducted as well as the specified visual examination. The examination results by both methods are in satisfactory compliance with applicable acceptance criteria.
ISSUE 7 Employment of the welding proceduIe (WPS-111), as well as proper preheat and interpass temperatures, metlod of temperature measurement, and weld rod storage should be verified, preferably by direct contact with weldirg craftsmen.
b' RE.SO_UTION 7 Direct interviews with craf t supervisors, craf t foremen, Unit 1 I&C personnel and the craf t personnel themselves have been conducted.
All those interviewed were told to state what they knew to be fact. They were told that if they did not remember the actual facts to say so.
The results of these interviews are as follows:
Weld Procedure WPS-lll was used in the welding of the lif ting lugs.
o All of the full and partial penetration welds were preheated to o
20U oF.
The interpass temperatures were maintained between 2000F and '>000F.
o A calibrated pyrometer was borrowed from Unit #1.
(This was confirmed with lnit #1 personnel).
o Weld rod was stored in ovens which have calibrated thelmometers. A daily log is maintained of the temperatures.
ISSUE 8 A thorough visual and dimensional examination should be conducted on the load test frame to provide assurance that no unauthorized attactinents, modifications, or other oeviations are present.
RESO.UTION 8 Recovery Operations conducted an in@ection of the Head Lif t Load Test Assembly, Load Spreading Frame and Lower Missile Shield Lifting Assemblies to verify compliance with the design drawing.
The units were visually insoected to assure there were no unauthorized attachments or modifications to the assemblies. No unauthorized attactTnents or modifications were found.
Items found that do not show on the drawing were " tack welds" on the cross bracing that connects the W 24 x 104 members together.
Each bracing assembly has four tack welds, I
two on each side of the diagenals. These were single-pass, one to two inch long welos.
These tack welds were made to assist in lining up the members and to reduce in-containment time. The aaditional tack welos will have no adverse effects tocn the load carrying capability of the test frame assembly.
In addition to the visual inspection, dimensional checks weIe performed to establish that the items were fabricated and installeo in accordance witn the drawing. In all cases, fabrication and installation was found to be in compliance with the drawings.,-g-,.-e
+-
7 y-
e 4
C0fLLUSION Based upon the above identified issues and the resolutions provioed, and e@ecially in view of the extreme conservatism elucidated in the stress analysis presented in 1ssue 5, as well as the veracity of the weloing craftsmen exhibited during diIect interviews, it is concludeo that the lcao test frame is suitable for its intenced use as it now stanos.
Furthermore, based toon the conclusions of the polar crane load test SLR (which evaluates a complete failure and dropping of the entire test load), the load test frame may be used as-is without presenting undue risk to the health and safety of the public.
_3_