ML19260D966
| ML19260D966 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 02/07/1980 |
| From: | Baynard P FLORIDA POWER CORP. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| 3-0-3-A-3, NUDOCS 8002120677 | |
| Download: ML19260D966 (3) | |
Text
.
- -?? N =,
,l *
~
^
c
~
z s,
Florida Power February 7,1980 File:
3-0-3-a-3 Mr. Robert W. Reid Chief Operating Reactors Bran:5 #4 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Crystal River Unit 3 Docket No. 50-302 Operating License No. DPR-72 SMALL BREAK LOSS-OF-COOLANT ACCIDENT
Dear Mr. Reid:
As indicated in our letter to you, dated December 3, 1979, enclosed is our response to Question 1 of your November 21, 1979 letter concerning smell break loss-of-coolant accident.
If you have any questions concerning the enclosed response, please con-tact this office.
Very truly yours, FLORIDA POWER CORPORATION P. Y. Baynard Manager Nuclear Support Services PYBemhWO706 1951 317 8002120 General Office 3201 Tnitty-fourtn street soutn. P O Box 14o42. st Petersburg Fiorda 33733 e 813--866-5151
REQUEST FOR ADDITIONAL INFORMATION SMALL BREAK LOSS-OF-COOLANT ACCIDENT QUESTION 1 Transitions from solid natural circulation to reflux boiling anJ back to solid natural circulation cuy cause slug flow in the hot leg piping.
By use of analysis and/or experiment addres3 the mechanical effects of the induced slug flow on steam generator tubes.
RESPONSE
The loads imposed on the tubes of the OTSG during the postulated " slug flow" have been conservatively evaluated and found to be acceptable.
Based on very conservative assumptions, the end loading on each tube will be 21.5 lbf compared to a theoretical buckling load of about 700 lb.
f It was assumed for this analysis that a water level has been established in the hot leg piping and inside the tubes of 0TSG.
The transient con-sists of a " front" of solid water impinging on the primary face of the upper tubesheet.
The flow was assumed to be equal in full 100% power flow (about 70,000,000 lb/hr).
The load is assumed to be a suddenly-applied load. The upper tubesheet
- conservatively assumed to offer no resistance to the load and the lowei tubesheet is assumed to be fixed so that the entire load is absorbed by tubes directly under the primary in-let nozzle. The flow is assumed to not follow the diffuser so that the velocity impinging on the tubesheet is the same as the velocity in the 36-inch nozzle. Hot leg temperature is assumed to be 605".
The velocity in the 36-inch pipe would be 64.4 ft/sec.
By use of the momentum equation, the steady-state force on the upper tubesheet due to the velocity would be 16,080 lb.
There are about 1500 tubes in a f
36-inch diameter circle.
Thus the 32.160 lbf will result in 21.5 lbf per tube.
Since the cross-sectional area of each tube is 0.070 in. the monentary axial compressive stress in these tubes would be 307 psi.
PYBemhWO706 1951 318
STATE OF FLORIDA COUNTY OF PINELLAS P. Y. Baynard states that she is the Manager, Nuclear Support Services of Florida Power Corporation, that she is authorized on the part of said company to sign and file with the Nuclear Regulatory Commission the information attached hereto, and that all such statements made and natters set forth therein are true and correct to the best of her knowledge, informat 'en and belief.
bayy wl
._P. Y. #aynar v
s Subscribed and sworn to before me, a Notary Public in and for the State and County above named, this 7th day of February,1980.
l wu
/d Notary Public Notary Public, State of Florida at Large, My Commission Expires:
August 8, 1983 l951 319 CameronNotary 3(D12)