L-86-158, Documents 860327 Telcon Response Re Asymmetries in Steam Generator Tube Plugging in C-E Large Break LOCA Analysis,Per 860131 Submittal & 860310 Request for Approval
| ML17216A484 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 04/10/1986 |
| From: | Woody C FLORIDA POWER & LIGHT CO. |
| To: | Thadani A Office of Nuclear Reactor Regulation |
| References | |
| L-86-158, NUDOCS 8604150337 | |
| Download: ML17216A484 (4) | |
Text
REGULATORY INFORl"IATION DISTRIBUTION SYSTEl'1 (R IDS)
ACCEBBION NOR: 8604I8080 DOC. DATE: 86/04/IO NOQRIZED:
NO FACIL:050-389't. Lucie Planti Unit 2i Florida Power 5 Light Co.
AUTH/+IAllE AUTHOR AFFILIATION WOODY'. O.
Fl.orida Power Zc Light Co.
REC IP. gAI'lE RECIPIENT AFFILIATION THADANI>A. C.
PWR Pv object Div ectorate 8
DOCKET 0 05000389
SUBJECT:
Documents 860327 telcon v esponse re asgmmetries genev'ator tube plugg"ing i'n C-E large break LOCA 860131 submitted 5 860310 request for approval.
DIBTRIBUTION CODE:
AOOID COPIEB RECEIVED: LTR i
ENCL L TITLE:
OR Submittal:
Qeneval Distribution NOTES:
in steam analysis'er SIZE:
RECIPIENT ID CODE/NAME PWR-8 ADTS PWR-8 PEICSB PWR-8 PD8 PD 01 PWR-8 PEICBB INTERNAL: ADN/LFI'lB NRR/DHF /TBCB 04 COPIEB LTTR ENCL 1
0 2
2 5
5 1
0 1
1 1
REC IP IENT ID CODE/NAl'1E PWR-8 EB PWR-8 FOB BELLBOY D PWR-8 RSB ELD/HDS2 NRR/GRAB RQN2 COPIES LTTR ENCL.
1 1
1 1
0 0
EXTERNAL:
2@X LPDR NBIC 03 05 1
1 1
1 EG8cQ BRUSKE> S NRC PDR 02, 1
1 TOTAL NUI'lBER OF COPIEB REQUIRED:
LTTR 24 ENCL 20
't k,
Jl N
w91>/yg i
i FLORIDAPOWER & LIGHTCOMPANY APR 1
0198B L-86-I58 Office of Nuclear Reactor Regulation Attention:
Mr. Ashok C. Thadani, Director PWR Project Directorate II8 Division of PWR Licensing - B U. S. Nuclear Regulatory Commission Washington, D. C. 20555
Dear Mr. Thadani:
Re: St. Lucie Unit 2 Docket No. 50-389 C-E Lar e Break LOCA Anal sis By letter dated January 3I, l986 (L-86-37), Florida Power Bc Light Company (FPL) submitted the results of the latest large-break LOCA analysis for St. Lucie Unit 2.
On March IO, l986 (L-86-8I), FPL requested NRC staff approval of the new analysis.
By telephone conference on March 27, l986, FPL, with the assistance of our NSSS vendor>
responded to an NRC staff question about how asymmetries in steam generator tube plugging were addressed in the analysis.
The attached written response documents the information that we provided during the telephone conference.
Very truly yours, C. O. Woo Group Vi resident Nuclear Energy COW/MAS/gp
Attachment:
cc: Dr. J. Nelson Grace, USNRC, Region II Harold F. Reis, Esquire, Newman & Holtzinger 86pq~gpe>
PDR ADOC> 86P4l~
P C< PSPPP~89 PDR MAS3/005/ I PEOPLE... SERVING PEOPLE
ATTACHMENT NRC Request:
The large break LOCA,analysis for St. Lucie Unit 2 assumed l250 plugged tubes per steam generator. 'as asymmetric steam generator tube plugging considered?
If so, justify how the symmetric tube plugging analysis accommodates unequal plugging between the generators.
Response
The large break LOCA analysis of Reference I
assumed 1250 plugged tubes per steam generator.'owever, asymmetric steam generator tube plugging was considered and it was concluded that the symmetric tube plugging analysis implicitly covers unequal plugging between generators, provided no more than l250 tubes are plugged in either steam generator.
The basis for this conclusion is as follows:
Tube plugging affects primarily the refill/reflood portion of the large break LOCA transient.
Steam generator tube plugging will have no significant effect on the blowdown portion of the transient.
The main impact of steam generator tube plugging is to increase the resistance to flow passing through the primary side of the steam generator, thereby inhibiting steam venting from the core outlet plenum to the break.
This reduces the refill/reflood rates and increases the peak cladding temperature.
With regard to this effect, plugging fewer than l250 tubes in either or both steam generators will reduce the flow resistance and will improve the refill/reflood rates.
Consequently, a reduction in the number of plugged tubes in either steam generator'will reduce the peak cladding temperature relative to the analysis results with l250 plugged tubes in each generator (Reference I).
Reference I:
Letter L-86-37 from C. O. Woody (FPL) to F. J. Miraglia (NRC),
"C-E Large Break LOCA Analysis," January 3I, l986.
MAS3/005/2