ML18114A744
| ML18114A744 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 05/22/1979 |
| From: | Lainas G Office of Nuclear Reactor Regulation |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7906290642 | |
| Download: ML18114A744 (5) | |
Text
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- MEMORANDUM FOR:
FROM:
SUBJ~CT:
REFERENCES:
e e
MAY 2 2 19?0 G. Knighton, Chief, Environmental Evaluation, Division of Operating Reactors G. Lainas, Chief, Plant Systems Branch, Division *of *.
Operating Reactors -
-CONTAINMENT DEPRESSURIZATION FOR SURRY POWER STATION UNITS 1 & 2.
- 1.
Memorandum for W-.: Butler* from B. Grimes, Determination of-Surry 1 & 2 Containment Leak Rate for LOCA Reevaluation, dated July 28, 1977.
- 2.
- Memorandum for A. Schwencer from G. Lainas, Draft Safety Evaluation:
Net ~ositive Suction I-lead Available to Containment Recirculation Spray and low* 1~ead Safety Inject-ion Pumps, dated *March 5, 1979.
Plant Name:
Surry Nuclear Power Station Units 1 and 2.
Docket Nos*. :
50-280/281 Res pons i b 1 e Branch:
PSB, EEB, ORB 111 Project Manager:
- D. Neighbors Enclosed is a figure, which presents the containme11t LOCA depressuri zation for Surry plants, submitted by the licensee during our review of the adequacy of NPSH for the containment recirculation spray and the 1 ow head safety injection pumps.
We have reviewed the input parameters used by the licensee'to perform the depressurization analysis and concluddd (Ref. 2) that the analysis would result in a reasonably*
conservative calculation of the containeent depressurization time.
The times at which the containment atmosphere returns to 1 /2 of the peak calculated pressure, 1/4 of the peak calculated pressure and subat,nospheric condition are 1150.seconds, 1750 seconds and 2662 seconds, res pee ti vi ly.
The fmow through leakage paths from the containment to the atmosphere depends on tee path geometry and flow regime both of which are not very well defined.
However. we believe it would be conservative to assume i:
-.1 that *the flow is in the tur~alent re;i}me-.:. and the leakage is a function of th~ square root of the ratio of the reduced pressure over th~-'i 90629061/~
containment cal cu! ated peak pressure. !hus, we recommend. that ~ n I
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at the time the ontainment at osphere retu ns to 1/4 of ts peak calc lated BURNAM*pr s*sirre-............. '........... :............................................................... *_*....................................................
DAT!:..
NllC PORM 318 (9*76) NRCM 0240 U.S. GOV~ttNME!NT PRINTING OFFICE: 197. - 28!1 - 709
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Our §Eon NPSH may be -used to support this pressure transient for the DBA LOCA.
Contact:
D. Shum~
cc:
V.
. D.
R.
tL R.
R.
A.
G.
E.
. D.
J.
D
- X27110 Stello Eisenhut Vollmer Grimes De Young Tedesco Schwencer Lainas Adensam Shum Donahew Neighbors
'-f.
G. tainas, Chief, Plant Systems Branch Division of Operating Reactors
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EIUR!'!AMIE,>
.DATlt~
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FORM 318 (9*76) NRCM 0240 u.:1. GOVERNMe::NT PRINTING O... FICE: 1978 - 2GB - 7Gtl
e UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555
'MAY Z 2 1979 MEMORANDUM FOR:
G. Knighton, Chief, Environmental Evaluation, Division of Operating Reactors FROM:
G. Lainas, Chief, Plant Systems Branch, Division of Operating Reactors
SUBJECT:
CONTAINMENT DEPRESSURIZATION FOR SURRY POWER STATION UNITS 1 & 2
REFERENCES:
- 1.
Memorandum for W. Butler from B. Grimes, Determination of Surry 1 & 2 Containment Leak Rate for LOCA Reevaluation, dated July 28, 1977.
- 2.
Memorandum for A. Schwencer from G. Lainas, Draft Safety Evaluation:
Net Positive Suction Head Available to Containment Recirculation Spray and Low Head Safety Injection Pumps, dated March 5, 1979.
Plant Name:
Surry Nuclear Power Station Units 1 and 2.
Docket Nos. : 50-280/281 Responsible Branch:
PSB, EEB, ORB #1 Proj~ct Manager:
D. Neighbors Enclosed is a figure, which presents the containment LOCA depressurization for Surry plants, submitted by the licensee during our review of the adequacy of NPSH for the containment recirculation spray and the
- low head safety injection pumps.
We have reviewed the input parameters
- used by the licensee to perform the depressurization analysis and concluded (Ref. 2) that the analysis would result in a reasonably conservative calculation of the containment depressurization time.
The times at which the containment atmosphere returns to 1/2 of the peak calculated pressure, 1/4 of the peak calculated pressure and subitmospheric condition are 1150 seconds, 1750 seconds and 2662 seconds, respectively.
The flow through leakage paths from the containment to the atmosphere depends on the path geometry and fl ovJ regime both of which are not very well defined.
However, we believe it would be conservative to assume that the flow is in the turbulent regime*
and the leakage is a function of the square root of the ratio of the reduced pressure over the containment calculated peak pressure.
Thus, we recommend that in performing the analysis of the radiological consequences following a LOCA, a reduction of 50 percent in containment leakage rate bi assumed at the time the containment atmosphere returns to 1/4 of its peak calculated pressure.
e
- Our SE on NPSH may be used to support this pressure transient for the OBA LOCA.
Contact:
D. Shum, X27110 cc:
V. Stello D. Eisenhut R. Vollmer B. Grimes R. DeYoung R. Tedesco A. Schwencer G. Lainas E. Adensam D. Shum J. Donohew D. Neighbors G. Knighton A.
fa__;;-
Lainas, Chief, Plant Systems Branch Division of Operating Reactors
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