View source for 3F1194-10, Submits Preliminary Results of Refuel 9 OTSGs Tube Pull,Per Commitment in Response to 940426 Cal,Item 8.Preliminary Rept, Exam of Crystal River-3 Pulled SG Tubes Encl.Final Rept Will Be Provided by 950531

{{Adams
| number = ML20080B551
| issue date = 11/30/1994
| title = Submits Preliminary Results of Refuel 9 OTSGs Tube Pull,Per Commitment in Response to 940426 Cal,Item 8.Preliminary Rept, Exam of Crystal River-3 Pulled SG Tubes Encl.Final Rept Will Be Provided by 950531
| author name = Widell R
| author affiliation = FLORIDA POWER CORP.
| addressee name = 
| addressee affiliation = NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
| docket = 05000302
| license number = 
| contact person = 
| document report number = 3F1194-10, CAL, NUDOCS 9412050321
| package number = ML20080B554
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE
| page count = 2
}}

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D Florida C R ORA O Cryvtd River Urut 3 Dockst No. 60-302 November 30, 1994 3F1194-10 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

==Subject:==
Preliminary Results of Refuel 9 OTSG Tube Pull

==References:==
A. NRC to FPC letter, 3N0494-21, dated April 26, 1994 B. FPC to NRC letter, 3F0494-09, dated April 19, 1994

==Dear Sir:==

Florida Power Corporation (FPC) is hereby submitting preliminary results of the Refuel 9 Once Through Steam Generators (OTSGs) Tube Pull. Confirmatory Action Letter (CAL) Item No. 8 (Reference A) confirmed FPC's commitment to provide such results by November 30, 1994. FPC will provide the final report by May 31, 1995.                                     i FPC intends to use the final report as the basis for a license amendment.                                             !
The attached preliminary report provides information on destructive and non-destructive (NDE) examinations performed on sections of OTSG tube samples pulled during Refuel 9 (Spring 1994). The examinations performed include field and l                laboratory NDE as well as destructive examinations.                     However, the detailed analysis of the NDE examination results to the metallography results for determining probabilities of detection and accuracy in sizing will be provided in the final report (this detailed analysis will be performed as a B&W Owners Group Project). The attached report also discusses the observed tube degradation
!                morphologies and their structural and leakage integrity implications.
Two forms of degradation were observed in the pulled tubes,                                 pit-like intergranular attack (IGA) in the lower tubesheet crevice and in the first span (6-18 inches above the lower tubesheet secondary face as observed in the 1992 pulled tubes) and mechanical wear at the tube support plate land contact areas.
FPC has performed preliminary evaluations of the NDE detection performance, the causes, structural integrity and leakage implications of the intergranular T
l                       050108 CRYSTAL RIVER ENERGY COMPLEX
* 15760 W. Power Line Street
* Crystal River
* Florida 34428-6708 * (904)795-6486 A Florida Progress Company                                                    ,
9412050321 941130                                                                -   U     i PDR   ADOCK G3OOO302                                                               1 P                       PDR

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* l
* U. S. Nuclear Regulatory Commission
)     3F1194-10 l     Page 2 l
l degradation observed as the result of the tube pulled examinations.       FPC has concluded the degradation morphologies observed are consistent with those found during the 1992 tube pull project. Furthermore, such intergranular degradation is enveloped by previous evaluations regarding likely causes as well as structural and leakage evaluations (Reference B). Particularly, burst pressures obtained during the 1992 tube pull were compared to the burst pressures obtained in 1994. Those burst pressures (from best estimates of burst pressures of tubes tested in 1992 as well as from those tubes burst tested in 1994) are well above the Regulatory Guide 1.121 of three times the operating differential pressure (3 x 1350 psid).
Based on a recently performed study of wear in OTSGs, and preliminary comparisons of historical eddy current inspection data, FPC also concludes that the growth of wear degradation observed at tube support plates is either non-existent or slow and easily monitored. The wear marks have no significant affect on burst pressure.
FPC believes the tube pull effort has greatly increased our knowledge of the condition of our steam generators. The results of this investigation support our conclusion that there are no degradation mechanisms which could impact the long l
term operation or safety of our steam generators.
l l     Sincerely, Rolf L. Widell, Director i     Nuclear Operations Site Support RCW:LVC Attachment xc: Regional Administrator, Region II Senior Resident Inspector NRR Project Manager}}