ML20002D288
| ML20002D288 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 01/15/1981 |
| From: | Trimble D ARKANSAS POWER & LIGHT CO. |
| To: | Novak T Office of Nuclear Reactor Regulation |
| References | |
| 2-011-19, 2-11-19, NUDOCS 8101200256 | |
| Download: ML20002D288 (2) | |
Text
e ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX 551 UTTLE ROCK, ARKANSAS 72203 [501) 371-4000 January 15, 1981 2-011-19 Mr. Thomas H. Novak Assistant Director for Operating Reactors Division of Licensing U. S. Nuclear Regulatory Comm.
Washington, D.C.
20555
SUBJECT:
Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Plan to Resolve Item I subtopic 4 of NRC August 5,1980 letter - USI A-12 (File: 2-1510)
Gentlemen:
As discussed with your Mr. John Fair in the December 17, 1980 meeting on USI A-12, attached is a detailed plan describing the proposed analysis method chosen to demonstrate adequate fracture toughness characteristics for the snubber attachment lug to the reactor coolant pump.
This plan is being submitted to outline our proposed method of addressing your concerns in item I subtopic 4 of your August 5,1980 letter.
Very truly yours,
& C. Y David C. Trimble Manager, Licensing DCT;.DEJ:1p Attachment
/
slonoc$lo MEMBEA MIDOLE SOUTH UTILITIES SYSTEM
A Plan Fcr the Fracture f
- Evaluation of ANO Unit 2 Reactor Coolant Pump - Motor Snubber Lugs
'A fracture mechani.cs evaluation of the reactor coolant pump (RCP) motor. snubber lugs will be performed in order to detennine the margin against brittle fracture for.the most severe combination of loading.and fracture resistance.
-1.
Fracture Mechanics Analysis Method The fracture mechanics analysis will be performed using the finite element computer program, MARC. Cracks of various sizes will be hypothesized to occur in two locations. The first is the location of the highest tensile stress near the pin hole, and the second is the _ location of the highest shear (tear-out) stress between the hole and the lug edge.
2.
Analysis Input The maximum specified loads, which are for the design basis earthquake (DBE) will be applied to the finite element model. Material properties for ise in the analysis and evaluation will be obtained by a literature and file search by CE. A lower bound toughness, KIC, taken from NUREG-0577 will be used if a higher to' ghness cannot be u
justified by data made available by the literature search.
p 3.
Evaluation The stress intensity factor, Kg, will be computed for the various hypothetical cracks and the DBE loadings and compared to the KIC of the material at the lowest service temperature.
The size of crack which would cause KI to be greater than KIC is considered the critical crack size.
A comparison of the critical crack size and the size of cracks which are reasonably assured to be detectable by preservice inspection will demonstrate the safety margin against brittle fracture.
Attachment (1) to A-CE-7864