ML17312B216
| ML17312B216 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 02/26/1996 |
| From: | Christopher Jackson NRC |
| To: | Thomas C NRC |
| Shared Package | |
| ML17312B213 | List: |
| References | |
| NUDOCS 9702110289 | |
| Download: ML17312B216 (10) | |
Text
~
~
~
~
From:
Chr istopher Jackson To:
WNP3. CRT Date:
2/26/96 8:24am
Subject:
Pallo Verde Unreviewed Good morning, j,c e~"
1 Safety guestion In reviewing the licensee calculations supporting their analysis of their identified unreviewed safety question I continue to have questions.
The phone call we had cleared up some of the misunderstandings, however, it appears that there are some computational errors.
Additionally, some of the methodology assumptions need to be justified.
I have attached my questions.
Please call me with any other questions X2947.
- Thanks, Christopher Jackson CC:
WNP5.AMH1, EWW 9702ii0289 96i2i7 PDR ADQCK 05000528 P'DR 7
r J
Request for Additional Information:
Calculation No. 13-NC-ZY-205 (I)
Please describe the calculation in greater detail than is currently provided.
State the initial conditions and where the conversion factors come from in equations I and 2 (it appears that there are computational errors between equations I and 2).
From the phone call you stated the specific heat ratio for ideal gas (air) was chosen.
State how accurate this is considering the flow will be from inside the tubes of the steam generators following a LOCA.
I believe in the phone call, you stated you would expect 10-15'F superheated steam and air.
How would this affect the results of the calculation?
Additionally, I was unable to locate the references you provided us on the phone call.
I was able to independently verify all the information with the exception of equation 5.
Please provide a derivation of the equation or a photocopied reference.
The calculations rely on the Fanno line relationships with the assumption that at the exit of the crack there is sonic flow.
Are these assumptions accurate or conservative?
Please justify the use of the Fanno line and sonic flow at the exit assumption.
(2)
The calculation assumes one crack of a unique area and loss coefficient with a leak rate of one gpm.
A more likely scenario is two or more cracks leaking a total of one gpm.
Please explain why the calculation remains accurate or conservative if there is more than one leaking crack.
Can this calculation be performed assuming two cracks with different loss coefficients?
Does this case yield the same or differ'ent results?
Please describe why this calculation is conservative for all possible cases?
The calculation states that there are five equations with five unknowns, however, it appears that there are actually six unknowns if you include the loss coefficient.
The calculations are solved assuming a range of loss coefficients from 0 - 200.
Please give a best estimate value for the loss coefficient and state the reasons?
Considering the largest flow rate resulted from the loss coefficient 200 state why this valve is conservative.
Would loss coefficients of 210, 250, or 300 be unreasonable, and why?
w g,p
Feb-21-96 15= 14 PVNGS Nuclear Reg Af'f'airs 602-393-5442 ARIWOMr4 PL/88K SERÃCE dOMPAM'-
SO YE'R'OS'IJOSEAR AEMERA77M% SiA770M Saon S. WtMTKRSSURO RO M4K sTaTNM Msc, TOMapau, aa.
asks~
NUCLEAR RECUG*iORY *FF*lRS
'D4TE:
2/oL I MUMSKR OV PACKS, lMCf.USMC COVER SNKET:
Oi C
es7k
~s 7'reeve:
Phone:
hone:
CC:
Phoae:
602 393.
V'ax Phone:
602 393.5442 gpMgggg.
Q Urgent 0'oe yowl Revfew Q Reply ASAP Q Please ecesncent V'%
6o e.
4W C~4~(
om Oi<'. chal KSe o, Ve.r erV V
4%
cc a,
N 5 c l4j 4/km< me Cc.
e.g<@
Sk M 4t roue C c
W4 f
. ~
Feb-21-96 15: 14 PVNGS Nuclear Reg Affairs 602-393-5442
~
02 0
$ummary The existing short term accident X/Q for control room used by PVNGS in calculation 13-NC-ZJ-205 is conservative and reasonable.
Areview ofalternative methodology for In line, "Point Source - Point rcccptor "(Murphy, Campc Eq 4) was performed using desert sigmas. Calculated value for X/Q at the plume centerline is 1.82E-3 (sec/m3) for releases from plant secondary side (i.e. ADVs ). However, re-calculating X/Qfor "containmcnt Diffus source - Point receptor" using these sigmas would be result in 42 pcrccnt reduction in X/Q ( from 1.96 E-3 to 1.13E-3 sec/m3).
Changes arc due to usc ofdcsert sigmas for stability group F verses usc of Pasquill sigmas, as-built distances (scc attached work shut).
Containment releases Secondary release Therefore, Ifnew methodology was used approximate doses to control room would be:
Thyroid Whole body 5.65 0.58 4.6 0.4 Total (1) 10.25 c 14.7 0.98< 1.46 (1) Contribution form recirculation leakage is not calculated however, this contribution would also be less than submitted, since distance from fuel building vent to the control room intake (west) is comparable to secondary discharge points.
li
Feb-21-96 15: 14 PVNGS Nuclear Reg Affairs 602-393-5442 P.O3 WORK SHEET Using desert sigma's applicable to PVNGS (ref.; UFSAR section 2.3.4.2), accurate distance fmm release point to intake ofessential control room HVACand corrected wind velocity for elevation of release.
Point source -point receptor X/Q can be calculated as follow; For desert sigma (ref. Yanskey, G. R, Markee, E. H., and Richter A. T., Climatography ofthe National Reactor Testing Station, 1DO-12048 ESSA Jan 1966. and XOQDOQ computer program Nureg/ CR 2919) sigma ~ a X Where for stability condition" F" sigma Y sigma Z 0.294 0.780 0.916 0.314 X
243 ft ( ref. drawing 13<MA408) sigma Y 15.167 and sigma Z 3.014 Using Murphy and Camp equation; X/Q 1/(3~ Pi ~ U~ sigma Y~ sigma Z)
U=Uref (Z/Zrei)'ref. D.J Wilson, contamination ofair intakes from roof exhaust vents, ASHRAE Trans,S2, 1976 )
Uref=l m/sec Zref 10m(or3211) and Z=94A(topof ADVstack194ft. and 7inches).
U 1.19 m/sec X/Q(point source to point receptor) ~ 1.823E-3 ac/m SiA'use source - Point receptor Using containment area above auxiliary building (261-180) ~ 80 it (24,38 m) a ~ 24.38 x 44.5 ~ 1085.0SS m ~
K~3/(S/d)'here d ~ 44.5 mand S ~74.07 m K 1.47,U 1m/sec using equation (6 ) of Murphy - Camp
1 li h