ML20107A138
| ML20107A138 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 02/11/1985 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 9749N, NUDOCS 8502190299 | |
| Download: ML20107A138 (5) | |
Text
9' p
O One First Natiord Plaza. Chicago, lltinois Commonwealth Edison Address Reply to: Post Office Box 767 Chicago, Illinois 60690 February 11, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Interim Operation of HVAC Systems NRC Docket Nos. 50-454 and 50-455 References (a): January 11, 1985 letter from T. R. Tramm to H. R. Denton.
(b): August 11, 1984 letter from T. R. Tramm to H. R. Denton.
Dear Mr. Denton:
This letter provides additional information regarding the interim operation of th Byron HVAC systems. Temporary leak limits are being imposed pending completion of testing on the auxiliary building ventilation system on or before July 1,1985. The status of the control rcom intake damper replacement is also described.
As indicated in reference (a) conventional dose assessment calcula-tions indicate that offsite doses could exceed the regulatory limits following a postulated LOCA if the auxiliary building ventilation system is not operable and there is significant leakage from ECCS systems carrying highly radioactive liquids outside the containment. There are sizeable conservatisms in these calculations and there is reason to believe that offsite doses would not reach those levels even if such an accident were to occur. To provide additional assurance that offsite doses would be acceptable during all postulated accidents, special interim limits will be established until testing of auxiliary building ventilation systems is complete.
The enclosed Figure 1 indicates the allowable power level at any given auxiliary building ECCS leakage rate without filtration of the auxiliary building air. The notes on the figure explain the basis for this limit.
Prior to exceeding 30% power at Byron 1, the leak rate from ECCS systems in the auxiliary building will be determined as described in reference (b).
Until testing of the auxiliary building ventilation system is complete, Byron 1 will not be operated at power levels exceeding 30% unless it can be shown that the auxiliary building ECCS leakage is below the corresponding limit shown in Figure 1.
Once the Byron 1 auxiliary building ventilation equipment is declared operable, these limits will no longer apply. Because of the short duration of this limitation, no ongoing surveillance will be conducted once the leak rate has been found to be acceptable for a given power level.
/*740/
8502190299 850211
/
PDR ADOCK 05000454 P
pyg
.?
H..R..Denton February ll, 1985 As-indictted in reference (a), bubble-tight-dampers are being-installed on the outside air dampers:for the control room ventilation system.
Figure 2 shows the location of the control room intake and exhaust points' with respect.to the containment.- The purge mode ~ air _ intake and exhaust dampers
~
will be installed at the first refueling on Byron 1.
Those ducts will be
. e expect to have the new blanked off until the new dampers can be installed.
W dampers'on the normal intakes installed and tested before exceeding 5% power.
If this cannot be accomplished,' those intakes-will be blanked-off and either train A or'B of the control room ventilation equipment will be operated continuously in the emergency mode (emergency makeup air filter in operation)
.until the bubble-tight dampers are installed and tested. Figure 3~shows the' system lineup in the emergency operating mode as well as the dampers that are-being replaced.
All of the new dampers will be installed by the end of the first refueling outage. These matters have been discussed with the EC Staff. The
- actions described here will be implemented on the basis of our understanding that they are acceptable to the tEC. Please direct further comments or
~
questions-to this office.
One signed original and fifteen copies of this letter are provided for tRC review.
Very truly yours,
[
/
h T. R. Tramm Nuclear Licensing Administrator 1m cc: Resident Inspector Byron 9749N
.. - -F7 p 1.
- l ALLOWABLE foa)G/2-1EI/EL.
)%A l'AK/ OOS i/AluEs 0F SCCS
^
1 Ecpu/ PorEN r LEA}c.A GE WITH AVX/L/AAY Bu/LD/N& ~
~
VENTIL A T/ o d S '(S TEM
.CA/ OPE AA 84.G' Y
l N u
ASSO/r1P7~ IONS:
y on_
l,
- 'lO,l6 control 80091 REC /ALCOLAT/ON'. f/LTE/Z. EFF/5.YENCl!
sitC CFM CAUTR.0L @o0M t/NF/tYER.ED' 1~A/LEAKAG-E
.I I e
N Il THyRojo boSE C AL.Cu/ 87/oNS
.lHCt vDE CON TA / AUTrou.S N
90
\\\\
Fa.o m :
1.
Conraiarreur Lenxnse.
.._ _ _ _ _ _ _. l I
.t. }Y1ASSIVE JECCS LEAKA6E (50GPet fot 30;O4. -
Il AT T = 3'l Houks.)
~
70 _
3.
THis ry' bay' ECC.S Conriavous - LEAKM&E
'^
.,l a
(
l As SilaDN ON duSLVE.
49 l t.
______ll______,______
% THYROID DOS 6 TO CONTf.0L. R.ootA OPERATORS I
~
o yy.
- '\\
lI l
Goven.N max / mum PO(.0ER. LEVEL
_ __I l Act E P TA 6Lt l 50 e
l M EAB Mb LPT DOSES ARE kJ/TH/d
- n g
l __ _ _. _._ _i _ _ _ _ _ _
4 ys.
\\*\\
I s
- Ioc.FKS~o PART loo L/*117s
'opgagr,u s. I
- f -
40 II 38" - -- -
1 I
.____ _..i__ _ _ __l______1_annes 33
___________l______
30 g-
..____.__I______'_ __ _ _ _ _ '. _ _ _ _. _ _; _ _ _ _ _ _ _I_ _ _._ _ _ _ -
(
lI l
l 1
l l
l 4.
.I i i
I I
l 20) lI i
8 l
i l
g 2
il 8
i l
j i;
I I
I I,
i g
l I
i 10' Il 1
l l
I l I
l l
l l:
l l
e Y
9 IO 20 30 ko 50
-50 90 h,
- Rux/LiMf Bu/ L b /NG.
EC.C. S LEAKn66 (GnLlMR)
- j-6 j;.E-L
.{
q-
.i
- q. q < g v. r - i, L -
,s.g,.-,
w:s ep t
.o
hd,O /E E d
!,,C C 5 T / & A /
Of 0 0 /'-./ T A o /-
bC'O/)i &R
[sv ^t'A Mi?.,C 3f8.cM)
$ D27"/ cAh
" ~..,,
,,, e f
.\\
fl/flL.
UNir1
/
vair 2.
') //MoWM6 Coxrniansvf
' Cae dm nT
(
\\
Buti.bM \\
C.-stTC.ut. lRMI, % W Cv%Ib2 N
==
ti//L
=
=
m m
A 5
5 f*:"> of. E.5
.q,%,-
- w r
- 7. w a
,o
^
0 140y.
$Uld 0/NG-3 4y T
.m
&ljiflWL &ff),5 fatt4 stue y dirL Drit w es TWAB/NE Buitbid6 j.
PuAs E Plac d /91 k Z 4 i'A t< E
^
~
~
A. blo n.1+1R L Moae Mitt rarnic.e 3.
Putt er & Mobt AtA [XMA UTI
$r._ N O M.!M A L. h l O b 6 h /hL -ZAffMid E..
~ '.
p e
==.
e-Putt se Mobs Min nrnic.s
[
. 3.
fM 11 6EH y / Wood Ai.A & fM kM.
l_.__'~~~
~
1 r.
Pua se Mabs. Air fxyusr l
I
~
Sounts
_/_/ / / ) 1 O fL 6 E x rtimus7-
~
W5,000<.WI 2
BUW}t.~of F -
.$[
n I
V e w w es um FM i-J p
l t
prasj' ftistsg CONTA OL-Arg /
> 4QvTnvE 3 f g
/
94;ooacrs
-yman s 4
ma.
C
' 7:
T As**81 S 5.Y 2
Fwn j
gOgJ d
-,v-n
- - esezecuenrun samy enim
, is m d ele *Wn t.-
FM toil.
O Gooo cvn FrLTE(L wasee+E twgosMr
//// /
)
J_!.
S&fJR 6
)
- L SW YEWTlYAT @
e-~-
o,,,,,2
~,
MME-UP nlN a.!
?eb, '-i.}: (y 6000 4ft*t..
./.ll
~.4
~
, f /t.fEG-. vat.s T '
Y-
~-
---