ML20092G972
| ML20092G972 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 06/19/1984 |
| From: | SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | |
| Shared Package | |
| ML20092G966 | List: |
| References | |
| NUDOCS 8406250314 | |
| Download: ML20092G972 (16) | |
Text
.
ATTACHMENT 1 POWER DISTRIBUTION LIMITS 3/4.2.3 RCS FLOW RATE AND NUCLEAR ENTHALPY RISE HOT CHANNEL FACTOR LIMITING CONDITION FOR OPERATION 3.2.3 The combination of indicated Reactor Coelant System (RCS) total flow rate and R, R, shall be maintained within the region of allowable operation i
shown on Figurt 3.2-3 for 3 loop operation.
Where:
N FAH
(
a.
Rj = 1.49 [1.0 + 0.2 (1.0 - P)] '
R b.
R 2 * [1-RBP(BU)]
THERMAL POWER c*
P
=
RATED THERMAL POWER Fh=MeasuredvaluesofFhobtainedbyusingthemovableincore d.
detectors to obtain a power distribution map.
The measured values of F shall be used to calculate R since Figure 3.2-3 s
includes measurement uncertainties of-5-f4 for flow and 4% for s
incoremeasurementofFh,and e.
RBP (BU) = Rod Bow Penalty as a function of region average burnup as shown in Figure 3.2-4, where a region is defined as those assemblies with the same loading date (reloads) or enrichment (first core).
APPLICABILITY:
MODE 1.
ACTION:
k With the combination of RCS total flow rate and R, R utside the region of j
2 acceptable operation shown on Figure 3.2-3:
a.
Within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> either:
(
1.
Restore the combination of RCS total flow rate and R,j R to within the above limits, or 2
2.
Reduce THERMAL POWER to less than 50% of RATED THERMAL POWER and reduce the Power Range Neutron Flux - High trip setpoint to less than or equal to 55% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
SUMMER - UNIT 1 3/4 2-8 8406250314 840619 DR ADOCK 05000
POWER DISTRIBUTION LIMIT BASES HEAT FLUX HOT CHANNEL FACTOR and RCS FLOWRATE and NUCLEAR ENTHALPY RISE HOT CHANNEL FACTOR (Continued)
The control rod insertion lim'ts of Specifications 3.1.3.5 and c.
3.1.3.6 are maintained, d.
The axial power distribution, expressed in terms of AXIAL FLUX
(
DIFFERENCE, is maintained within the limits.
F will be maintained within its limits provided conditions a. through H
- d. above are maintained.
As noted on Figures 3.2-3 and 3.2-4, RCS flow rate and F may be " traced off" against one another (i.e., a low measured RCS flow H
N rate is acceptable if the measured F is also low) to ensure that the calculated DNBR will not be below the design DNBR value.
The relaxation of Fh as a function of THERMAL POWER allows changes in the radial power shape for all permissible rod insertion limits.
R,ascalculatedin3.2.3andusedinFigure3.2.3,accountsforFh 1
less than or equal to 1.49.
This value is used in the various accident analyses where F influences parameters other than DNBR, e.g., peak clad H
temperature and thus is the maximum "as measured" value allowed.
R, as 2
defined, allows for the inclusion of a penalty for rod bow on DNBR only.
Thus
\\
knowing this "as measured" values of F and RCS flow allows for " tradeoffs" H
in excess of R equal to 1.0 for the purpose of offsetting the rod bow DNBR penalty.
When an F measurement is taken, an allowance for both axperimental error q
and manufacturing tolerance must be made.
An allowance of 5% is appropriate for a full core map taken with the incore detector flux mapping system and a 3% allowance is appropriate for manufacturing tolerance.
The radial peaking factor Fxy(Z) is measured periodically to provide
(
assurance that the hot channel factor, F (Z), remains within its limit.
The F
limit for Rated Thermal Power (FRTP)0 as provided in the Radial Peaking x
Factor Limit Report per specification 6.9.1.14 was determined from expected power control maneuvers over the full range of burnup conditions in the core.
When RCS flow rate and F are measured, no additional allowances are H
necessary prior to comparison with the limits of Figures 3.2-3 and 3.2-4.
N Measurement errors of for RCS total flow rate and 4% for F " have been 0
allowed for in determination of the design DNBR value.
/
SUMMER - UNIT 1 B 3/4 2-4
ATTACHMENT 1 (cont'd)
Page #3
.li li :l! ' ili:.il! ililiil Ui + M $ Uili; ;l :IMUi:M$illiUill;il; liii
?0%
- h MEASUREMENT UNCERTAINTIES OF3:5% FOR FLOW i {!.
AND 4.0% FOR INCORE MEASUREMENT OF F,g ENE gi g
d,
}'
!!!!li.'.;' :. i. ! '!!. !.
li.
!!U l
F l'
.t-
- ~ ~~A-
- * 2 *
- n -
- L'*
i
,RE Gl'o A I R2Glo vE ACCEPTANBLE ACCEPTABLE r
OPERATION.
OPERATION REGION i.
.p, FOR R, ONLY FOR R, fr R 2
38 i.
?
i
.i 9
.j.
I l
_..J.
UNACCEPTABLE !
OPERATION t
j 38 REGION I
j t
.[.
a, O
k 6
i p
6 l
- g l
us
- t. -3 4
3 3
E
- 3 3 34 l4
-!g i
e C
['
a r-V d
o t
a 4
. L' W
.t.
o I
.(1.022, 32.13) eaoM
-T-j j
-].
l I
.p
..j.
m l
.i.
t
.t.
.j.....g t
l l
~~
I j-t F
i t
n'./ /. /:/ /.E././. /.1.1:.1. A l l
'......L..
.L...
. a...
s t
f.
l 76/i /./ ) / f /
f (lW///i Qj}'}g
(/d' 29,67.)
l l
178 94 Ni~T#
l-8
-(Ac,2% B9)
)[Gjg,Q 9 6 % AW/ -
y;a,'u.n
- m. ers ;
~ ~ ~ -
~ ' * ~
go 'gg;ijg))' - '*~
"12 % ATP'
"~m" 90 % MTf' UA 26<49
\\
28
+
l l
i i
I I
26 0.90 0.95 1.00 1.06 1.10 l
l i
R, = F,"g [.%.0 4.2 H.%
R = R,((1.0-RBP (BU))
2 l
NOTE: When operating in Region III, the restricted power levels shall be considered to be 100% of Rated Thermal Power (RTP) for Figure 2.1-1.
Figure 3.2-3 RCS FLOW RATE VERSUS R Suitt1ER - UNIT 1 3/4 2-10
r ATTACHMENT 1 (coat'd) Page #4 f
~
680
=
-n =
=+
m._
.+..a-UNACCEPTABLE'
=~'"
- alu !".
~
OPERATION
/
T$ =.._:.-
5
._.t r-
...:-.-en (2f.,661.5),i
=-t:.
- =
u
=. -4 ;.
r u=
_ _ - _....a___
g
. u--
7--, - - -
- =
... =
=:--
.tu=_.=.=y---
. 4..
. 2400 e...
w
-[ - -
w
-- := :t=
-4..
m
. z g.
Q p
. w:.: PSI A
-..__.. m (2y.,65. 2.) :
-- -r
. r f
m.
4
~
- - - - + - -
m a.
i 1 (80%,639);_.,..,
w 2 640
... -"4.....
' h ----I 4._
(2%,635) :
,2000;..
- a.._
.. :t=;.
m g
_;,..m,
=4 ;. ;.,;,_
up,_
x.-
~~
" D::. '629):
(84%
e
~
A Z
PSIA-
---4 r-:n f m
- ~%.i..:l:!:
- 2250 g-
. ij
- :. un.... :
' ' g :" ~ --
l ew
... PSIA m
i d
ihhc n_5 S.....
"Iikki.- 2 $!E EE 2
< 620
- " -Tt:M =-
.5:
=-1:.
"See
- (2%,625) - l '
=:
2 t
w_%
h l
- IN{i-- kEli2-iiI :[kI.IDDikk;~i i
=%NXaa 4-ii86sW%
1
=WE==(98%,607)u
. k=
. =
'O -
... (-w.. k.--
.._P~: -
N".~' ' ' - ~
p
=
- 2 PSI A r'
' ' ' '" " ' ' " l"" t 2
. d 2
i s~~
4 600 e
~-
_ '}.. _.
'me..q. --
._g.
s
.....+
,,., _i_
i 8
(120%,594)
- -=..x.
...c=1=
-:=::=
- - + =
1.
-~-~ -
=
- =:n
- n.. : im-u_-.--
+ (104%,593)! -
i r
o
._ t m
- =f. =
I. -
--4
- 5_ % =rA. (120%,587)
=.:-
= r....
-- + -
- N
+:
o
..i ACCEPTABLE-
..Ipinjj-ik jj-ihi.-..jj{j:-]
U
!, OPERATION _;,
m
.iji:
.;_;hl.
i
< 580 i
=_
- = r; ijii ii $) :jijj2: 22= iiii}:h:phii=
g j
- =
(120%,575) ur
-..._ j - -
- " _.---d:~: ". m-s u
~~,
I
...m:r=-.......--:- --
t
.... fr...
i i
iiEr~....l _
r==:n-*...==::" I.."
f un
=~i d.. (120%,568) i
..u :ny:.
..:p
= c
.:afu 560 0
20 40 60 80 100
- 120 POWER (PERCENT)
(
Figure 2.11 Reactor Core Safety Limit Three Loops in Operation
- When operating in Region III of Technical Specificial 3.2.3
(
(Figure 3.2-3), the restricted power level must be considered 100% RTP for this figure.
SUPNER - UNIT 1 2-2
,i
,I
't-
' t' ATTACHMENT 2 c
h REACTOR COOLANT SYSTEM (RCS) FLOW RATE MEASUREMENT The RCS flow rate measurement is required by Technical Specification 4.2.3.2 at least once every thirty-one (31) EFPD.
This is accomplished.with elbow tap flow instrumentation using the process computer display af ter normalizing the elbov tap flow measurement with a precision heat balance acrose'the steam generators.
The precision heat balance is performed once per eighteen (18) months according to Specification 4.N.3.5.
The elbow tap flow measurement is presently the bas'is for the Technical Specification total flow measurement uncertainty.
Normalizing the elbow tap flow measurement with the precision heat balance reduces the uncertainty by eliminating errors due to the transmitter calibration and temperature and pre'ssure effects.
Thus, with a more accurate determination of RCS flowrate, the required neasured flow rate can be reduced.
Whenever the process computer display is unavailable, the RCS
'2 flow rate will be determined using digital voltmeter (DVM) readings from the elbow tap process racks.
Specification 3.2.3, RCS Flow Rate and Nuclear Enthalpy Rise Hot Channel Factor, in the Standard Technical Specifications requires that total reactor flow (total flow'through the vessel from all loops) be'above some minimum value.
The minimum flow value is Thermal Design flow corrected for the total flow measurement uncertainties.
Historically, the uncertainty has been specified as 3.5%.
Flow measurement uncertainties much-less than this can be achieved by using modern statistical error analyses and normalizing elbow tap: flow!1ndications with s
a precision calorimetric flow measurement.
The a: curacy achieved by this technique" depends primarily on the measurement procedure employed and;how,Nell the instrument errors are understood and controlled by plant personnel.
The normalization ofL the elbow tap flow measurement with the precision calorimetric flow calculation, the measurements required and the measurement uncertainty analyses are described in the following paragraphs and tables.
Reactor coolant loop flow is determined from the steam generator thermal output, corrected for the loop's share of the net pump heat input, and the enthalpy, risei rth h) of the coolant.
Total ~ reactor flow is the sum of the individual loop f lows.
Table 1 lists the. calorimetric equations and defines the terms.
i To establish the;overall flow measurement uncertainty, the accuracy and relationship to RCS flow of each luistrument used for the calorimetric measurements must be determined.
Instrumentation for
)
I
I~
ATTACHMENT 2 (cont'd)
Page #2 the elbow tap flow indication is depicted in Figure 1.
Table 2 provides the list of components involved in the precision calorimetric flow calculations.
The overall loop flow measurement uncertainty is the statistical summation of individual uncertainties (accounting for interactive effects where necessary) and appears at the bottom of Table 2 To establish the overall uncertainty for the process computer and DVM elbow tap flow measurement, the accuracy and relationship of all instrumentation to the RCS flow must be determined.
There are several components (transdacer, converter, isolator, etc.) which contribute to the overall uncertainty of the measurement.
Tables 3 and 4 list and define uncertainties from the elbow tap flow transmitters to the process computer and DVM using three (3) taps (one (1) per loop).
The overall loop flow measurement uncertainty is the statistical summation of individual uncertainties and appears in Table 3 ann 4.
Table 5 statistically combines the overall precision calorimetric measurement uncertainty and the uncertainty of the elbow tap flow indication using three (3) taps.
The total flow uncertainty using three (3) normalized elbow taps (1 per loop) with the process computer display is 2.0%.
The total flow uncertainty using three (3) normalized elbow taps (1 per loop) with the DVM reading is 11.99%.
Based upon this, the RCS flow measurement uncertainty included in Techncial Specification 3/4.2.3 is conservatively chosen to be 2.0%
In summary, individual loop flow is determined by performance of a precision calorimetric and these values are used to normalize elbow tap measurements.
The loop flow measurements are summed to arrive at the total RCS flow.
The measurement uncertainty is determined by statistically combining precision calorimetric and elbow tap flow measurement uncertainties.
A precision calorimetric flow measurement must be performed to normalize the elbow taps to take credit for this particualr measurement uncertainty.
This proposed change has no adverse safety implications since the Thermal Design flow rate which is utilized in various safety analyscs is unchanged.
ATTACHMENT 2 (cont'd)
Page #3 TABLE 1 REACTOR COOLANT LOOP FLOW CALCULATION (QL)
WL=
(Y)[QSG - Op +
g--](Vc)
[h -hcl H
Where:
WL Loop flow (9Pm)
=
Qsg =
Steam generator thermal output ( Btu /h r. )
J QL Primary system net heat losses (Btu /hr.)
=
Number of loops N
=
Op Reactor coolant pump heat added (Btu /hr.)
=
Hot leg enthalpy (Btu /lb.)
hH
=
cold leg enthalpy (Btu /lb. )
hc
=
cold leg specific volume (cu. ft./lb.)
V
=
c 3
0.1247 gpm/(ft /hr)
Y
=
(h
- hg)Wp Q3g
=
s Steam enthalpy (Btu /lbm)
Where:
h
=
s Feedwater enthalpy (Btu /lbm) hp
=
Feedwater flow (LBM/Hr)
Wp
=
(K) (Fa)m/Pp AP Wp
=
Feedwater venturi flow coefficient Where:
K
=
Feedwater venturi correction for thermal expansion Fa
=
pp Feedwater density (lb/cu.ft.)
=
Feedwater venturi pressure drop (inches H 0)
Ap 2
=
ATTACHMENT'2 (cont'd)
Page #4 TABLE 2 CALORIMETRIC FLOW MEASUREMENT UNCERTAIt: TIES UNCERTAINTY INSTRUMENT
% POWER OR COMPONENT ERROR
% FLOW Feedwater Flow Venturi K
~+ 0.5% K
~+ 0.5%
Thermal Expansion coefficient Temperature 1 0.54*F i 0.06%
Material i 5.0%
Density Temperature 1 0.54*F i 0.04%
l Pfessure 1 60 psi i
DP Cell Calibration 1 0,5%
1 0.39%
l DP Cell Reading Uncertainty i 1.0%
1 0.78%
Feedwater Enthalpy Temperature 1 0.54*F i 0.08%
Pressure 1 60 psi Steam Enthalpy Transducer Calibration i 1.5 psi 0.006%
Moisture Carryover 1 0.25%
1 0.22%
Primary Enthalpy Tg RTD i 0.5'F i 0.95%
TH RTD Bridge 1 0.554*F i 1.044 TH Temperature Streaming i 1.2*F i 2.27%
TH Pressure Effect i 12.8 psi 1 0.102 (including drift allowance)
TC RTD i 0.5 F i 0.775 TC RTD Bridge 1 0.554*F i 0.868 t
TC Pressure Effect i 12.8 psi 1 0.026 (including drift allowance)
Net Pump Heat Addition i 20%
1 0.085%
Total Loop Flow Uncertainty
~\\/L eY' 3.096 Total Reactor Flow Uncertainty 1.788
~
ATTACHMENT 2 (cont'd)
Page #5 FIGURE 1 FLOW INDICATION INSTRUMENTATION Reactor Coolant System Flow 0 - 120,000 gpm Elbow Tap Differential Pressure 0 - 400 INWC 4
Flow Transmitters 9 total /3 per loop Barton 752 4 - 20 MADC Westinghouse 7300 Process Control Cabinets l
0 - 10 VDC s
Process Computer DVM 0 - 120% Digital 0 - 10 VDC Digital l'
Display Display
ATTACHMENT-2 (cont'd)
Page #6 TABLE 3 PROCESS COMPUTER ELBOW TAP RCS FLOW INDICATION UNCERTAINTY Parameter
%RCS Flow Uncertainty PMA
+0.30%
PEA 10.36%
SCA
+0.00%
SPE 10.00%
+0.00%
SD 10.72%
+0.50%
RTE 10.00%
RD
+0.72%
ID 10.36%
+0.36%
l l
I l
1/2
[(PMA)2+(PEA)2+(SCA+Sg)+2+(STE)2+ (SPE)2 +
(RCA+RD)2 + (RTE)2 + (ID)
(RO)2 CU =
Where:
Channel Uncertainty CU
=
PMA =
Process Measurement Accuracy PEA =
Primary Element Accuracy SCA =
Sensor Calibration Accuracy SPE =
Sendor Pressure Effects Sensor Drift SD
=
STE =
Sensor Temperature Effects RCA =
Rack Calibration Accuracy Rack Drift RD
=
Computer Isolator Drift ID
=
Allowance for Noisy Signal RO
=
RTE =
Rack Temperature Effects Total Loop Channel Uncertainty with 1 tap =
+1.577%
Total RCS Channel Uncertainty w/3 loops
+0.910%
=
.. =.
ATTACHMENT-2 (cont'd)
Page #7 TABLE 4 DVM ELBOW TAP RCS FLOW INDICATION UNCERTAINTY Parameter
%RCS Flow Uncertainty PMA 10.30%
P EA 10.36%
SCA
~+0.00%
SPE 10.00%
+0.00%
SD 10.72%
+0.50%
~10.00%
RTE RD
~+0.72%
RO 10.36%
+0.25%
1/2
[(PMA)2 + (PEA)2 + 'SCA+S 2 + ( STE) 2 + ( SPE) 2 +
(RCA+RD)2+(RTE)2+(RO)g)+ (DVM)2)
CU =
Where Channel Uncertainty CU
=
PMA =
Process Measurement Accuracy PEA =
Primary Element Accuracy SCA =
Sensor Calibration Accuracy SPE =
Sensor Pressure Effects Sensor Drift SD
=
STE =
Sensor temperature Effects RCA =
Rack Calibration Accuracy Rack Drift RD
=
Allowance for Noisy Signal RO
=
DVM =
Digital Voltmeter Uncertainty RTE =
Rack Temperature Effects l
Total Loop Channel Uncertainty with 1 tap =
11.535%
Total RCS Channel Uncertainty w/3 loops 10.886%
=
ATTACHKENT 2 (cont'd)
Page #8 TABLE 5 TOTAL RCS FLOW UNCERTAINTY Total Precision Calorimetric RCS Flow Uncertainty 11.788% (Table 2)
=
Total RCS Elbow Tap Channel Uncertainty utilizing process 10.910%
(Table 3) l computer display
=
Total RCS Elbow Tap Channel Uncertainty utilizing DVM readings 10.866%
(Table 4)
=
By Sum of Squares Method:
Total RCS Uncertainty using process
+2.00%
computer display
=
Total RCS Uncertainty using DVM readings
+1.49%
=
(
Based on the above:
Total RCS Uncertainty included in Specification 3/4.2.3
+2.0%
=
r
r ATTACHMENT 2 (cont'd)
Page 49 RCS FLOW RATE LESS THAN THERMAL DESIGN (TD) FLOW Current Technical Specification 3.2.3, Figure 3.2-3 limits operation to'less than 5% of Rated Thermal Power (RTP)should measured RCS Flow be less than the TD flow used in the plant safety analyses.
This Technical Specification does not recognize the possibility of a long term reduction in flow, nor the various trade-of fs allowed by the relationships between flow, departure from nucleate boiling (DNB), and core power.
These trade-offs can be used to justify continued operation at some reduced maximum allowed power if the measured RCS flow is less than the TD flow.
I It is widely recognized that the relationships between core power, flow, and DNB are:
3 Flow 1%
(Eq. 1)
=
3 DNB 1%
3 Power 1%
(Eq. 2)
=
BDNB 1.8%
Thus the relationship between Power and Flow is:
9 Power 1%
(Eq. 3)
=
8 Flow 1.8%
ATTACHMENT 2 (cont'd)
Page #10 Based on a conservative assumption that the measured RCS flow will be no lower than 95% of TD flow, it is requested that a region of acceptable operation be added to Figure 3.2.3 for:
95% TD Flow f RCS Flow 1 100% TD Flow Considering the relationship given by Equation 3, it is recommended that the maximum power level for this region be reduced by 2% for each 1% reduction in measured flow below TD flow.
This conservative restriction of core power is the equivalent of an RCS flow increase ranging from approximately 2.6% - 13.0% in terms of DNB margin for flow deficits up to 5%.
i Operation of the plant in this region within the specified I
power restriction does not result in increased Tavg, thus there I
is no temperature impact on the DNB margin.
The Technical Specifications and accident analyses results have been evaluated to determine the impact of operating within the defined new region of Figure 3.2-3 with the imposed restrictions.
In all cases, sufficient margin exists to allow dontinued plant operations.
No Techn'ical Specification limits require modification, including core limits, OT AT, OP OT, and Power Range Neutron Flux High setpoints.
The core limits remain the same due to the increased margin to DNB afforded by the power reduction and interpretation that they will be valid for the restricted power levels.
This implies that under these conditions the restricted power level should be considered to be 100% of Rated Thermal Power (RTP) for Figure 2.1-1.
With this restriction applied to the Safety limits, there is no change in the core limits thus the OT AT and OP A T trip setpoints remain unchanged.
Utilizing the latest Westinghouse data, the uncertainty in the instrumentation for the Power Range Neutron Flux High trip function is 4.7% span (or 5.7% RTP).
With a normal assumption of reactor trip at 109% RTP, the uncertainty analysis verifies that a trip will take place at 109% RTP plus 5.7% uncertainty o r 114. 7 % RTP.
A 5% reduction in RCS flow requires a trip at 115.2% RTP.
Therefore, adequate margin exists in the instrumentation such that no change in the nominal setpoint is necessary.
ATTACHMENT 2 (cont'd)
Page #11 If the measured RCS flow is equal to or greater than TD flow, operation will be in the acceptable region of the present Figure 3.2-3 and the requirements of this specification will remain unchanged.
The addition of the new region to Figure 3.2-3 is only requested to preclude a needles, reduction to 5%
RTP should the measured RCS flow be less than TD flow.
l l
(
)
i i
l i
i L
1 l
i l
1 i
l l
4
(
t
e ATTACHMENT 3 SIGNIFICANT HAZARDS CONSIDERATION l
The proposed amendment to the Technical Specifications does not involve a significant hazards consideraton for the following reasons.
The proposed change to Figure 3.2-3 to account for a reduction in measurement uncertainties (3.5% to 2.0%) for RCS flow has no ef fect on the Thermal Design flow.
The Thermal Design flow which is utilized in the various safety analyses remains unchanged.
In regard to the change which defines allowable power levels for an RCS flow rate less than 100% of Thermal Design flow, thermal-hydraulic sensitivity studies have shown that this power / flow tradeoff is conservative with respect to DNB margin.