ML20199D068
| ML20199D068 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/13/1999 |
| From: | Scherer A SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9901190286 | |
| Download: ML20199D068 (1) | |
Text
-
%s(j EDISON 2"Lem sOUntIRN CAttf 0RNIA A. I:dward Scherer E
l ra nnw* n u nwour.**=">
January 13, 1999 U. S. Nuclear Regulatory Commission Attention: Document Control Desk l
Washington, D. C. 20555 Gentlemen:
l l
Subject:
Docket Nos. 50-361 and 50-362 Proposed Technical Specification Change Number NPF-10/15-498 Reactor Trip Operating Bypass Removal Setpoints, Supplemental Information San Onofre Nuclear Generating Station (SONGS) Units 2 and 3
Reference:
Letter from D. E. Nunn (SCE) to Document Control Desk (NRC) dated November 23, 1998,
Subject:
Docket Nos. 50-361 and 50-362, ProposedTechnicalSpecificationChangeNumberNPF-10/15-498, Reactor Trip Operating Bypass Removal Setpoints, San Onofre Nuclear Generating Station (SONGS) Units 2 and 3 By the referenced letter, Southern California Edison (SCE) submitted Proposed Technical Specification Change Number (PCN)-498, a request to revise Technical Specification (TS) 3.3.1, " Reactor Protective System (RPS) Instrumentation -
Operating."
In a telephone conversation with B. L. Mozafari (NRC) on January 11, 1999, SCE agreed to supply the enclosed calculation, J-SBA-023 CCN No. N-1 of September 24, 1998, in support of our request.
If you have any additional questions, please contact Mr. Jack Rainsberry at 949-368-7420.
Sincerely, 0 f A.
M 990t190286 990113 PDR ADOCK 05000361,.
P PDR.
Enclosure cc:
E. W. Merschoff, Regional Administrator, NRC Region IV J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 2 and 3 J. W. Clifford, NRC Project Manager, San Onofre Units 2 and 3 B. L. Mozafari, NRC Division of Reactor Projects, Project Directorate I-2
/
- I)
P. O. Ikn 128 e
OOl San Clemente. CA 92674-0128 949 368 7501
[
l'ax 949 368-7575
Southern C11tfornia Edison Company CALC. NO.
PAGE TOTAL NO. OF J-SBA-023 fgpg CN NO "I
I CCN NO.
INTERIM CALCULATION CCN CONVERSION :
CALC.REV. # h BASE CALC. REV.
UNIT CHANGE NOTICE (ICCN)/
k h
0
,2&3 CCN NO. CCN-
' CALCULATION CHANGE NOTICE (CCN)
CALCULATION SUBJECT : DNB/LPD/ LOG POWER TRIP BYPASS COVER PAGE ENGINEERING SYSTEM NUMBER / PRIMARY STATION SYSTEM DESIGNATOR Q-CLASS CALCULATION CROSS-INDEX 1201
/
SBA 11 y New/ Updated index included
=
CONTROLLED PROGRAM OR PROGRAM / DATABASE NAME (S)
VERSION / RELEASE NO.(S)
_.J DATABASE ACCORDING TO Sita Programs / Procedure impact?
SO123-XXIV 51 O NO O YES AR No.980602271 L_! PROGRAM g DATA BASE
] ALSO, LISTED BELOW l
1.BRIEF DESCRIPTION OF ICCN / CCN:
The d: sign of the DNB/LPD/ Log Power Bypass logic and setpoint cannot satisfy the current Technical Specification 3.3.1, Table 3.3.1-1, Notes (a) and (d) as wntten. The only setpoint which satisfies both specifications simultaneously is exactly j
1E-4 percent power, a precision which cannot be achieved. This is because the same bistable is used to do both functions, wh:re the DNBR/LPD bypass is automatically removed at the bistable setpoint on an increasing power and the loganthmic pow:r bypass is automatically removed at the bistable reset (hysteresis) on a decreasing power. As such, the two can never be equal and occur at the same time.
1 Another problem is that the original safety analysis uses 1E-4% log power as the trip setpoint in both directions when eviluiting CEA withdrawal transients initiated from subcntical and low power conditions. The bistable has only one trip s:tpoint, which currently satisfies the low power conditions of the safety analysis. The subentical conditions are not bounded by the safety analysis because the actual setpoint is the bistable reset, which occurs at a value lower then 1E-4% log power.
The purpose of CCN N-1 is to provide the following:
a.) Establish the 1E-4% Log Power Bistable Decreasing Trip (Reset) Setpoint.
b.) Establish the Upper Operational and Lower Analytical Limit for the 1E-4% Log Power Bistable Trip Setpoints.
c.) Calculate the Allowable Values forthe 1E-4% Log Power Bistable Trip Setpoints.
d.) Calculate Trip Setpoint Margin.
e.) Calculate Margin to Log Power Trip.
i CCN N-1 is an entire document CCN for continuity only. There is a variation in page numbenng due to format changes associated with the text processing.
INITIATING DOCUMENT (DCP, FCN, OTHER)
AR 980602271 REV.
- 2. OTHER AFFECTED DOCUMENTS (CHECK AS APPLICABLE FOR CCN ONLY):
) YES
- NO OTHER AFFECTED DOCUMENTS EXIST AND ARE IDENTineD ON ATTACHED FORM 26-503
- 3. APPROVAL :
DISCIPLINE / ESC : Controls /NEDO
\\
h S. Foglio 4 h Qh2 Q h. fl2ff6 l
i ORIGINATdR (Pnnf naj/ sign /dat FLSWgnature/date)
OTHER (Signature /date) l (yf W. Phoenix U
-CI dn/p IRE (Pnnt name/xgn/date)
OTHER (Signature /date)
OTHER (Signature /date)
- 4. CONVERSION TO CCN DATE h-d Q 4b bbCh &
SCE CDM - SONGS ses 2em., aav 2 6/96 (REFERENCE $01:3.xxivJ 15)
T E'
c CE e 2 0 01 /1 q1:!$0/52 53 W
ICCN NO2 5}
CALCULATION CROSS INDEX N4 lPAGE lof iiq PRettu. CCN nO-CCN CONVERSION:
Calculation fJo J-SBA-023 Sheet No of CCN NO CCN-INPUTS OUTPUT Does the output Calc rev These interfacing calculations and/or documents Results and concluses of the subject calculate are interface calc /
Identify output mterface calc I number and provide inptd to the subject calculation, and if revised used in these interfacing calculations and I or document require document CCN, DCN TCN/Rev_,
revision?
FIDCN or tracking number responsibk
~ y re,quke revision of_the subject calculation.
documents.
YESINO tr.a FLS incais Calc / Documerd No.
Rev. No.
Calci Document No.
Rev. No and date O & M Manual SO23-941-4S, 7/83 SONGS Unit 2 & 3 Setpoint List Revision 26 YES NEDOTRAK RMB 91-019 Safety Channel 90030 Subtask 2 0
Surveillance Operating Revision SONGS Unit 2 & 3 Instrument Index Revision 42 YES NEDOTRAK RMB 91-019 instruction SO23-!!-5 5 thru 5 8 900tOA Subtask 2 PPS Calculation SO23-944-C50, Revision DBD-SO23-470, Excore Nuclear Revision 0 YES NEDOTRAK RMB 91-019 CE-NPSD-570 03-P instrumentation System Des %n Basis Subtask 2 Document DBD-SO23-470. Excore Nuclear Revision 0 SONGS 2 & 3 Technical Unit 2 NO Instrumentation System Design Specifications Amend 101 Basis Document Unit 3 Amend 90 DBD-SO23-TR-EQ Revision 0 M37582 Revision 10 90010A Revision 42 JS-123-103C Revision 0 SONGS 2 & 3 Technkal Unit 2 Specifications Amend 101, Unit 3 Amend 90 90030 Revision 26 SCE 26-424 REV 2 8/95 (
REFERENCE:
SO23-XXIV-7.15]
CALCULATION CROSS INDEX
" " ICN NO.
PAGE lof nReuu CCN CONVERSION: [
Calculation No.
J-S B A-023 Sheet No.
of CCNNO. CCN-s INPUTS OUTPUT Does the output Calc rev.
These interfacing calculations and'or documents Results and conclusons of the subject calculation are interface calc 1 Identify output interface calc /
numte and provide input to the subject calculation, and if revised used in these interfacing calculations and / or document require document CCN, DCN TCN/Rev.,
responsible
-- y reguire revisson of the subpct calculation documents.
~~~--
he ma revision?
FIDCN or tracking number FLS Ws
~~ ---
and date Calc / Document No.
Rev. No.
Calc / Document No.
Rev. No O & M Manual SO23-941-45, 15 SONGS Unit 2 & 3 instrument inder 47 YES AR 980602271 Safety Channel 90010A CCN N4 PPS Calculation SO23-944-C50 3
DBD-SO23470. Excore Nuclear 3
YES AR 980602271 (CE-NPSD-570-P, Revtsion 7)
Instrumentation System Design Basts Document W
/
UFSAR Urvts 2 & 3 14 l&C Procedures SO23-II-51 thru 5 8 9-2. 9-1, 9-YES AR 980602271 g/ f 3.9-1,13, l2- / g 13,13-2,13
//
Calculation NFM-2/3-TA-0008 SONGS 2 & 3 Technical Und 2 YES AR 980602271 Specifications Amend 127 PCN-498 Unit 3 4
Amend.116 l
Unit 2 Cycle 10 Reload Ground 0
Calcutation J-ZZZ-069 0
NO Rules, RGR-U2-C10 Outer-Tolerance Notircation Program (OTN)
L Neutron Flux Level Startup 1
Channel Removal Signal, J-SEA-l 023 l
SCE 26-424 REV. 2 S/95 [
REFERENCE:
SO23-XXIV-T.15]
___m
WES&L DEPARTMENT ICCM NO1 Q
CALCULATION SHEET PREUM. CCN NO.
PAGE 4 of 1 CCN CONVERSION:
Profet or DCP / FCN N/A Caic No. J-SBA-023 CCN NO. CCN-f
\\
, Subject DN8/LPD/ LOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D. McQuade 03 19-93 E. Quinn 03-19-93 D
NEI TABLE OF CONTENTS
- 1. O Purpose.
.5 l
l
- 2. O Results/ Conclusions and Recommendations.
.9 l
- 3. O Assumptions 16 l
- 4. O Design input 18 l
- 5. O Methodology
.25 l
- 6. O References
. 33 l
- 7. O Nomenclature
.. 35 l
- 8. O Calculations
. 36 l
- 9. O Simplified Block Diagram
.50 l
Attachment A:
SONGS 2 & 3 CPC and CEAC Data Base Listing. CE NPSD-337-P, Rev. 00-P, Dated January 1986. Pages 14 and 24.
Attachment B:
SCE Electronic Mail; From D. Bockhorst (SCE) to J. O'Brien (SCE).
Subject:
Criticality Point, Dated March 18,1993.
l l
SCE 26-426 REV O 6/94 (REFERENCE SO123-XXN-7.15)
1 NES&L DEPARTMENT ICCM NOJ 5'3
"^
CALCULATION SHEET PREuM CCN NO.
PAGE 5 of'&'
CCN CONVERSION:
Pr6;ect or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-
/
, Subject DN8/LPD/ LOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D.McQuade 03 19-93 E Qumn 03-19-93 jO zg2 1.0 Purpose 1.1 Background / Purpose l
.1 Purpose The U.S. Nuclear Regulatory Commission inspection Report l
(Reference 6.10) addressed the area of weakness concerning setpoints that had been improperly delineated and were not consistent with the design basis for respective systems. As a result of this l
i inspection, SCE committed to reconstitute the design basis for all l
safety-related setpoints. This calculation will provide an evaluation of whether the Departure from Nucleate Boiling Ratio (DNBR) / Local Power Density (LPD)/ Log Power Trip Bypass at 10"% Reactor Power has a safety function related to it. If it is determined to have a safety function, further analysis will encompass the setpoint and total loop uncertainty values for this bypass.
The purpose of CCN N-1 is to provide the following:
a.)
Establish the 1E-4% Log Power Bistable Decreasing Trip (Reset) Setpoint.
b.)
Establish the Upper Operational and Lower Analytical Limit for the 1E-4% Log Power Bistable Trip Setpoints.
l c.)
Calculate the Allowable Values for the 1E-4% Log Power Bistable Trip Setpoints.
d.)
Calculate Trip Setpoint Margin.
e.)
Calculate Margin to Log Power Trip.
.2 Background
The 10"% Bistable is an operating bypass which performs three functions. Two functions of the bistable are to allow manual bypass of the Departure From Nucleate Boiling Ratio (DNBR) and High Local Power Density (LPD) trips. The bypasses are manually inserted by the operator when reactor power is less then 10"%. The bypass is automatically removed when power is greater than 10"%.
SCE 26426 REV 0 854 (REFERENCE SO123-XXN-7.15)
I NES&L DEPARTMENT ICCN NOJ f3 CALCULATION SHEET PREUM CCN NO.
PAGE 6 of $
CCN CONVERSION:
Project or DCP / FCN N/A Calc No..i-SBA 023 CCN No. CCN.
/
, Subtect DN8/LPO1.OG POWER TRIP BYPASS Sheet No.
of
]
REV ORIGINATOR DATE IRE DATE REV CRIGINATOR DATE IRE DATE 8
1 0
D. McQuade 03 19-93 E.Cumn 03 19-93 gy2 l
The third function of the bistable is the High Log Power Level Bypass.
This bypass disables the High Logarithmic Power Level Trip during l
reactor startup. The bypass is manually inserted by the operator when reactor power is greater than 10 d% and is automatically removed when power is less than 10"%.
The background for CCN N-1 is provided in the following paragraphs which describe two problems associated with setting the 1E-4%
Bistable setpoints. Supplemental information is documented in AR 980701034 and AR 980602271.
The design of the DNBILPD/ Log Power Bypass logic cannot satisfy the current Technical Specifications (TS) as written. TS 3.3.1, Table 3.3.1-1, Note (d) states the DNBR/LPD bypass "shall be automatically removed when thermal power is [ greater than or equal to] 1 E-4
[ percent]." TS 3.3.1, Table 3.3.1-1, Note (a) states the logarithmic power bypass "shall be automatically removed when thermal power is
[less than or equal to] 1E-4 [ percent]." The only setpoint which satisfies both specifications simultaneously is exactly 1E-4 percent power, a precision which cannot be achieved, nor is desirable. This is because the same bistable is used to do both functions, where the DNBR/LPD bypass is automatically removed at the bistable setpoint on an increasing power and the logarithmic power bypass is
{
automatically removed at the bistable reset (hysteresis) on a decreasing power. Hysteresis in the bistable is an important and desirable feature to prevent the bistable from chattering at the setpoint, and to prevent inherent noise from setting and resetting the bistable and triggering a spurious safety system operation. As such, the two can never be equal and can not occur at the same time.
This first problem will be resolved by rewording Notes (a) and (d) in Table 3.3.1-1 of the TS to reflect the operation of the DNB/LPD/ Log Power Bypass logic. This will require a revision to the TS, which is not a purpose of CCN N-1. However, values calculated in CCN N-1 may be used in the TS revision.
l Another problem is that the original safety analysis uses 1E-4% log power as the trip setpoint in both directions when evaluating CEA l
withdrawal transients initiated from subcritical and low power conditions. As discussed above, the bistable has only one trip setpoint, which currently satisfies the low power conditions of the SCE 26-426 REV 0 8/94 (REFERENCE SO123-XXN-7.15)
i NES&L DEPARTMENT ICCN WOJ p
CALCULATION SHEET PRELIM. CCN NO.
PAGE 7 ofg CCN CONVERSION:[
Project or DCP / FCN N/A Calc No. J SBA-023 CCN NO. CCN.
l Suw.et DNBNOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 8
0 D. McQuade 03-19-93 E.Qumn 03-19-93 l
EIl safety analysis. The suberitical conditions may not bounded by the i
safety analysis because the actual setpoint for the suberitical conditions is the bistable reset, which occurs at a value lower then 1E-4% log power.
This second problem will be addressed by reevaluating the safety analysis using an Upper Operational Limit (UOL) and Lower Analytical Limit (AOL) that takes into consideration the total loop uncertainty for the 1E-4% log power bistable setpoint plus margin. The TLU is provided in Revision 0 of this calculation and is slightly modified by CCN N-1.
j l
.2.1 DNBR/LPD Bypass The DNBR and LPD bypass, which bypasses the low DNBR and high LPD trips from the CPC, is provided to allow system tests at low power i
when pressurizer pressure may be low or reactor coolant pumps may be off. This bypass is necessary to permit CEA withdrawal during startup because the CPCs will be in a tripped condition when the part-length CEAs or shutdown CEAs are fully inserted. The bypass may be manually initiated if power is below 10"% and is automatically removed when power level increases above 10"%.
CPC protection is not required at subcritical conditions. The minimum power used in the CPC for the DNBR and LPD calculations is 20% of rated power (Reference 6.12). When the shutdown CEAs are not fully withdrawn or the part-length CEAs are fully inserted, large radial peaking factors are used in the DNBR/LPD calculations which will insure a reactor trip. Therefore, the CPCs have to be bypassed to permit CEA withdrawal during startup.
.2.2 High Log Power Trip Bypass The High Logarithmic Power Trip provides a reactor trip from a high l
neutron flux when the neutron level is at or below the minimum range i
of the power range nuclear instrumentation. A high flux may result, for instance, from an uncontrolled CEA withdrawal from a subcritical l
condition. The High Logarithmic Power Level Trip bypass is provided to allow the reactor to be brought to the power range during a reactor startup. The bypass may be manually initiated above 10"% power l
and is automatically removed when power decreases below 10"%.
SCE 26426 REV 0 M4 (REFERENCE SO123-XXIV 7.15) l
m NES&L DEPARTMENT ICCM NOJ 3
l N4 CALCULATION SHEET PREuM CCN NO.
PAGE 8 o%
CCN CONVERSION:
Project or DCP / FCN N/A Calc No J-SBA 023 CCN NO. CCN-
, Sutnect DNB/LPD/ LOG POWER Trip BYPASS '
Sheet No.
of
(
REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
i 0
D. McQuade 03-19-93 E.Qumn 03-19-93 D
i E3I 1
This setpoint allows the high log power trip to be manually bypassed once the conditions have been established that the high log power trip function is no longer needed.
1.2 Degree of Accuracy l
l The results of this calculation are based on the statistical methods in accordance with SCE Engineering Standard for instrument Setpoint/ Loop Accuracy Calculation Methodology, JS-123-103C Rev. O, and Revision 2 for CCN N-1 (Reference 6.7). A 95% probability at a 95% confidence level is used.
1.3 Intended Uses/ Acceptance Criteria The results of this calculation are intended for the uses described in section 1.1, purpose of this calculation.
The voltages and values in this calculation apply only to the bistable, not to indications in the control room. The state of the bistable is displayed to operators via lights and alarms which are not directly connected to the analog control board indicators, whose accuracy is a separate issue.
This calculation /CCN involves a plant protection system operating bypass that is described by using the numerical value of the "setpoint" in the name of the function. The bistable card that performs the operating bypass function also has the "setpoint" value in its name. In addition, this particular bypass / bistable j
function operates in both directions using the reset of the "setpoint" as a setpoint in the opposite direction, resulting in the function having both increasing and decreasing setpoints. For purposes of discussion, and in identifying with existing nomenclature,1E-4% will be viewed as a nominal value in the context of describing the DNB/LPD/ Log Power Trip and 1E-4%
Bistable operating bypass. Actual setpoint values are clearly identified when used.
i SCE 26-426 REV O ES4 (REFERENCE SO123-XXN-7.15) 7.
l l
1 1
NES&L DEPARTMENT ICCN NO1 y
CALCULATION SHEET PREUM CCN NO.
PAGE 9 of _
CCN CONVERSION: !
Project or DCP / FCN N/A Calc No. J-SBA-023 CCHNO. CCN-of '
Subtect DN64.PO4.OG POWER Trip BYPASS Sheet No.
REV ORIG!NATOR DATE IRE DATE REV ORIGINATOR DATE 1RE DATE g
0 D. McQuade 03-19-93 E.Qumn 03 19 93 6
$2 4
2.0 Results/ Conclusions and Recommendations 2.1 Results
.1 Calculation Results The established and calculated values associated with the High Log l
Power and DNB/LPD Bypass are listed in the table below and Figure 1:
s Bistable increasing Decreasing (Reset)
Units Setpoint Setpoint
% Log Power V dc
% Log Power V de l
Setpoint / Reset 1 E-4 3.699 7.944E-5 3.599 l
Setting Tolerance 1.02?E-4 to t0.01 8.414E-5 to iO.025 9.773E-5 7.499E-5 Allowable Value 1.5E-4 3.875 4E-5 3.305 l
UOL/LAL 4.1 E-4 4.312 1.48E-5 2.869 l
}gk; w j
0.485 Total Loop g9 0.485 a
.~
Uncertainty i_ri;:F:s M..
u.a.awi:yw9
- n. s w e;e m Setpoint Margin 1;J2.M;MQ 0.128 GiMedeDd's 0.245 l
Lyr5v Wm
?DM!g'ifv U T a r~cv s
Setpoint Margin to W DYa y 2.932 l
l Log Power Trip
[$hjh4f hg-
- 1..
y SCE 26 426 R% 0 tV94 (REFERENCE S0123 XXIV-7.15)
NES&L DEPARTMENT ICCN NO3
]
"'I CALCULATION SHEET PREUM. CCN NO.
PAGE io of CCN CONVERSION:
Pro}ect or DCP / FCN N/A Calc No. J-SBAE CCN NO CCN.
[
Subject oNBtPo/ LOG POWER TRIP BYPASS Sheet No.
of GEV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE y
0
- o. McQuade 03-19-93 E.Qumn 03-19-93
${0 2
200% Power 10 Vdc UAL 2.0% Power 8.0 Vdc UAL - TLU, 0.837% Power 7.622 Vdc JM R8 837%-TLU, 0
0.351% Power 7.244 Vdc 3
10 '% Power 1
10-2% Power
)
x 1
10-3% Power 2
UOL 4.1x10"% Power 4.312 Vdc AVs l
1.5x10d% Power 3.875 Vdc tsp 10d% Power 3.699 Vdc increasing Reset -
7.944x10 5% Power 3.599 Vdc Decreasing AVd 4x10 5% Power 3.301 Vdc I
LAL 1.48x10-5% Power 2.869 Vdc I
LOL 10-5% Power Notations UAL: High Log Power Trip UAL UOL: High Log Power Bypass UOL LOL: Lower Operational Limit p
IS 2WA denotes Margin to High Log Power Trip 2x109 Pown Mc tsp arrows indicate signal direction -increasing or decreasing AVi; Allowable Value increasing Setpoint Figure 1 AVd: Allowable Value Decreasing (not drawn to scale)
(Reset) Setpoint l
SCE 26-426 REV 0 8/IM (REFERENCE SO123 XXIV-715) l
WES&L DEPARTMEMT ICCM NOl Q
CALCULATION SHEET PREUM. CCN NO.
PAGE 11 of W L_
CCN CONVERSION:
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Project or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-l i
Sub}ect DNB/LPD/ LOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D.McQuade 03 19-93 E.Cumn 03-19 93
${6 2
Figure 1 on the previous page incorporates values shown in Table 1.
i Noteworthy items in Figure 1 are the Upper Analytical Limit (UAL) of l
2% RTP for the High Log Power Trip less the High Log Power Trip's I
Total Loop Uncertainty (TLU ) twice, and the amount of margin 3
between the High Log Power and Bypass Trip setpoints.
The Upper Analytical Limit has the High Log Power Trip TLU, l
subtracted twice to ensure adequate margin between the High Log Power Trip and the High Log Power Trip Bypass bistables. T he "UAL
- TLU " term is the 2% Analytical Limit minus its associated TLU 3
(Reference 6.8), resulting in a 0.837% High Log Power Trip setpoint.
l The same TLU, is then subtracted again from the 0.837% power setpoint in a conservative effort to account for the accuracy of the High Log Power Trip bistable itself. It is necessary to ensure that the uncertainty associated with the High Log Power Trip bistable does NOT overlap with the calculated uncertainty plus margin for the High Log Power Trip Bypass setpoint. The TLU value for the High Log 3
Power Trip already includes the bistable uncertainty component and therefore is a conservative value.
The shaded region of Figure 1 shows the amount of margin between l
the High log Power Trip Bypass UOL and the High log Power Trip setpoint minus TLU. This large amount of margin,2.932 Vdc or 29.3%
3 of Span, allows the operator sufficient time to perform the manual bypass of the High Log Power Trip without causing an inadvertent trip.
.2 Discussion of Results The setpoint for this bistable is currently set to permit manual bypass of the High Log Power trip and to automatically reinstate the DNBR/LPD trip at 10"% power increasing power. This bistable also automatically reinstates the High Log Power trip and permits manual bypassing of the DNBR/LPD trip when the bistable setpoint resets on l
decreasing power. The input range for the log channel is from 2 x 10-8% to 2 x 10+2% power while the output is from 0 to 10 volts. The l
output to input sensitivity is then i volt per decade. Both the High Log l
Power trip and the High Log Power bypass receive an input signal l
from the same detectors and signal conditioning electronics.
4 Since one of the functions of the bistable is to permit a bypass and automatically reinstate the High Log Power trip, the setpoint needs to SCE 26426 REV O 8/94 (REFERENCE SO123-XXIV 7.15)
i l
MES&L DEPARTMENT ICCN NO/
CALCULATION SHEET PREUfGCN NO.
PAGE 12 o l
CCN CONVERSION:
Project or DCP / FCN N/A Cale No. J.SBA-023 CCN NO. CCN-
[
Subject DNEULPD/ LOG POWER TRIP BYPASS Sheet No.
of l
REV ORIGINATOR DATE tRE DATE REV ORIGINATOR DATE IRE DATE 8
o
- o. ucou.a.
os-is-s3. E. ouinn oa-is.es i
i be set to ensure that this will occur prior to the High Log Power inp setpoint which is nominally set at 0.837% power plus the bistable uncertainty. Another aspect of the bypass setpoint is that sufficient t
difference between the High Log Power Trip Setpoint and the Bypass Setpoint must exist to allow the operator sufficient margin to perform the manual bypass without causing an inadvertent trip.
Another function of the bistable is to automatically reinstate and permit the bypass of the DNBR/LPD trip.
Parametric analysis have indicated that the lowest initial power level of 4
10 % suberitical core condition results in the closest and fastest approach to the fuel design limits during a CEA withdrawal transient.
Initially suberitical, zero power CEA withdrawal transients are l
terminated by the High Log Power trip. Analysis has also shown that, l
for CEA withdrawal transients initiated from a power level of 1E-5%
l l
and higher, the accident is terminated by either the DNBR/LPD trips or a high Pressurizer Pressure trip. From the accident analysis it can be seen that above 1E-5% power the protective function of the High Log Power trip is not required to protect the core once the neutron flux has l
been stabilized. However, it is important that the High Log Power Trip Bypass not be set any lower than a power level at which the core is to be considered unstable. Historically for SONGS 2/3, the power level at which neutron flux level is considered stabilized has occurred at approximately 10-5% power (Attachment B). This CCN N-1 uses a Lower Analytical Limit (LAL) of 1.48E-5% to ensure that the accident analysis limit is not exceeded. Also, the analysis considers that the DNBRILPD trips have been inserted above 4.1E-4% power. Although not a safety limit, the 4.1E-4% power serves as an Upper Operational Limit (UOL) when analyzing low power conditions. It further ensures sufficient margin for manual bypass operation.
Therefore, a bypass setpoint of 10"% for this trip function is acceptable from a safety analysis point. Also, as stated above, the bypass setpoint must be set such that the operator has sufficient time I
to manually bypass the High Log trip without causing an inadvertent trip. If the calculated uncertainties for the bistable are applied to the setpoint, sufficient margin must be allowed for the manual bypass operation. in the case where too small a margin exists, additional margin would have to be added to allow the operator to perform this 4
operation without causing an inadvertent trip.
SCE 26426 REV o 8/94 (REFERENCE SO123-XXIV 7.15)
NES&L DEPARTMENT ICCM NOJ 3
N4 CALCULATION SHEET PREuM CCN NO.
PAGE 13 o W CCN CONVERSION, Protect or DCP / FCN N/A Calc No. J SBAC CCN NO. CCN-Subject DNBtPD/ LOG POWFR TRIP BYPASS Sheet No, G,
l REV ORIGINATOR DATE IRE DATE REV ORIGINATOR ' DATE 1RE L
g 0
D. McQuade 03-19-93 E.Qumn 03 19-93
- L Based on the above, the present bistable increasing setpoint of 10"%
l is acceptable. This setpoint allows the operator sufficient margin for implementing the manual bypass without causing an inadvertent trip.
The decreasing setpoint, or reset of the increasing setpoint, will l
reinstate the High Log Power trip when it is required by the accident analysis to provide core protection for CEA withdrawal transients initiated from suberitical conditions.
2.2 Conclusions The existing setpoints for the High Log Power and DNB/LPD trip bypass are l
sufficiently conservative to meet its functional requirement. According to the Combustion Engineering Plant Protection System Setpoint Calculation (Reference 6.8), the High Log Power trip of 0.837% corresponds to 7.622 volts while the calibration procedure for the bypass bistable (Reference 6.5) indicates that the 10"% setpoint corresponds to 3.699 volts. There is approximately 3 decades of power between the two setpoints. This is sufficiently conservative to allow the operator time to perform the manual bypass while also automatically reinserting the High Log Power trip protection (on reset) when required by the safety analysis. In the case of the DNB/LPD l
trip bypass there is also sufficient margin between the bypass setpoint and the point at which the CPC's use actual neutron power to calculate the DNB/LPD trip.
2.3 Recommendations it is recommended that the following documents be revised to include this calculation as a reference:
DELETED l
SONGS Unit 2 & 3 Instrument index; Report No. 90010A The current setpoints are acceptable for the bistable to perform its l
intended function. It is recommended that the present setpoints not be t
revised.
{
2.4 Limitation and Verification This calculation should only be used for the purpose described in section 1.
SCE 26426 REV O 894 (REFERENCE SO123-XXIV-7.16)
NES&L DEPQRTMENT ICCM NO)
CALCULATION SHEET PREUM. CCN NC.
N4 PAGE 14 of CCN CONVERSION:
i Prom or DCP / FCl4 N/A Calc No J.SBAe CCN NO.
CCN-
[
Subject DNEtPD/ LOG POWER TRIP SYPASS Shoot No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE 1RE DATE 8
0 D. McQuede 0519-93 E.Qumn 0519-93 gy2 No special tests are required to confirm the results of this calculation.
This calculation does evaluate for seismic conditions.
This calculation does not apply to loop uncertainties which may result from harsh environmental conditions.
The parametric analysis of the CEA withdrawal transient assumed that 1E-5%
l would be the point at which the protection system would switch from the High Log Power Trip to the CPCs for protective action to prevent core damage tv this transient. This CCN N-1 uses a Lower Analytical Limit (LAL) of 1.48E-5%
to ensure that the acadent analysis limit is not exceeded. It also considers 4.1E-4% the point at which the switch has occurred by. Redsing the setpoints in this CCN N-1 may require reanalyzing the transient to assure satisfactory results.
2.5 Interfacing Calculations, Documents and Drawings Interfacing calculations, documents and drawings are listed in the calculation Cross-Index and section 6.0, references.
The Excore Nuclear instrumentation System Design Basis Document (reference 6.6) will require updating to include the decreasing (reset) trip setpoint for the 1E-4% bistable. AR 980602271 will track this updat:
Final Safety Analysis Report, Section 7.2, will be affected. Changes to this report will result from Licencing Proposed Change Number 498 (PCN-498).
Units 2 & 3 Technical Specifications, Table 3.3.1-1, Notes (a) and (d) are affected. Licencing Proposed Change Number 498 (PCN-498) will initiate and track this change.
SONGS 2/3 Instrument Index, SCE Dwg. 90010A Rev. 42, will require updating to include the trip setpoint allowable values and the decreasing l
(reset) trip setpoint for the 1E-4% bistable. AR 980602271 will track this j
update.
Update l&C Calibration Procedures SO23-il-5.1 thru 5.8 with calculation results. AR 980602271 will track this update.
4 2.6 Interfacing Organizations SCE 26-426 REV 0 854 (REFERENCE SO121XXN 7.15)
NES&L DEPAQTMENT JCCM NO1
'3
"^
CALCULATION SHEET PRELIM CCN NO.
PAGE 15 of CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J.SBAe CCN NO CCN.
[
Subject DN8/LPD/ LOG POWER TRIP BYPASS Sheet No.
of i
REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE l DATE g
i 0
D.McQuade 03-19-93 E.Qumn 03-19 93 0
$2 4
Per the requirement of NES&L SO123-XXIV-7.15, Sections 3,4, and 6 of this calculation have been sent to the responsible System Design Engineer and NGS Maintenance Engineering.
1 Other affected disciplines as identtiMd and documented on the Document l
Review Form (Design Verification Form for CCN N-1) SCE 26-422-1 are l
included in the review process.
i I
i j
j j
i 4
r=
SCE 26-426 REV O ELS4 (REFERENCE SO1:3 XXIV-7.15)
NES&L DEPARTMENT ICCN NO1
$3l CALCULATION SHEET PREuM CCN NO.
PAGE 16 of W CCN CONVERSION: [
Praject or DCP / FCN NsA Calc No. J-SBA 023 CCN NO CCN-Sub ect DN8/LPO4.OG POWER TRIP BYPASS Sheet No., _
c' t
l BATE g
REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE 0
D. McQuade 03-19-93 E,Qumn 03-19-93 0
$2 l
4 3.0 Assumptions 3.1 Assumptions Which Do Not Require Verification
.1 Radiation Error (Rei)
The effects for normal non-accident radiation doses for the device in this calculation is assumed to be included in the drift allowance per section 3.6.1.5 of reference 6.7.
.2 Drift Error (Da )
3 For devices with no vendor drift data specified, a drift value equal to the stated accuracy for a 30 month period will be applied. This is considered conservative based on engineering judgement, since it is assumed that actual drift values were so small as to be considered insignificant by the vendors or that the vendors encompassed drift data in other published specifications.
.3 Ambient Pressure Sensitivity (Pe,)
The components evaluated in this calculation are not sensitive to the ambient pressure variations exhibited at their locations.
.4 Power Supply Effect (Ps,)
The power supply effects are assumed to be included within the performance specification.
.5 Temperature Effect (Te3)
For the NT-4 bistable the specification for reproducibility stated by the manufacturer is assumed to include the effects of ambient temperature variations.
SCE 26-426 REV 0 8/94 (REFERENCE SO123-XXIV-7.15)
s WESal. DEPARTMENT ICCM NO1 3
N4 CALCULATION SHEET PREW CCN NO.
PAGE 17 of CCN CONVERSION.
Calc No. J-$8A423
[
CCN NO CCN-Subject DN8&PD4.OO POWER TRP BYPASS i
Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
C D. McQuade 03-19-93 E. Quenn 03-1W93 D
$2 4
.6 Area B Temperatures Per the UFSAR, the minimum normal temperature of the control room complex (including the control room cabinet area) is 70*F. The peak temperature for this area per table 0-1 of Reference 6.3 is 75'F. It is assumed that a i2.5'F control band exists about the minimum and peak temperatures yielding a 67.5*F to 77.5*F (10*F) temperature band. This 10*F temperature band will be used to calculate ambient temperature effects on equipment located in these areas.
3.2 Assumptions Which Require Verification There are no assumptions used in this calculation which require verification.
SCE 26-426 REV O 8S4 (REFERENCE SO123-XXIV.7.15)
NES&L DEPARTMENT ICCM NO1 55
~
CALCULATION SHEET PREUM. CCN NO.
PAGE 18 of W CCN CONVERSION: !
Propct or DCP / FCN N/A Calc No. J-SBA-023 CCN NO CcN-
, Subject DNBA.PD/ LOG POWER TRIP BYPASS Sheet No.
of j
REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 8
0 D. McQuade 03-19-93 E.Qumn 03-19 93 j43 4.0 Design input 4.1 The Upper Analytical Limit for the High Log Power Trip setpoint has been l
determined to be the Analytical Limit for the High Log Power Trip at 2% Power 1
less twice the TLU for the High Log Power Trip (Reference 6.8).
l 4.2 For increasing power, the point at which an operator may bypass the High Log l
3 Power Trip is a power level where the core is considered to stabilized and low power transients or excursions are unlikely. For decreasing power, the
)
i operator bypass will need to be reinserted prior to a power level where low power transients become increasingly difficult to control with the High Log Power Trip in bypass. The resulting value which meets both of these criteria will be 1E-5% RTP (Attachment B), which is defined as the Lower Operational
]
Limit (LOL).
4.3 The operating characteristics of the Excore Safety Channels are provided by the Operation and Maintenance Manual prepared by ABB/CE (reference 6.4).
4.4 The design input for this calculation is included in forms 1 through 4.
4.5 The data obtained from the Technical Specificati6hs is used for information j
and does not provide numerical input for the TLU calculation.
4.6 The attached Calculation Cross Index lists all reports and documents that provide numerical input for this calculation.
4.7 Where reference is made to the UFSAR this is the best source for the required data.
4.8 The Upper Operational Analytical Limit (UOL) and the Lower Analytical Limit (LAL) for the DNB/LPD/ Log Power Trip Bypass Setpoints are established at 4.1E-4% and 1.48E-5% Log Power respectively (Reference 6.14).
1 4.9 The DNBILPD/ Log Power Trip Bypass bistable trips on an increasing power.
The trip setpoint is adjustable. The bistable trip setpoint resets on a decreasing power at a fixed hysteresis of 0.1 V (Reference 6.4). The trip setpoint is referred to as the " increasing setpoint" and the reset is referred to as the " decreasing setpoint" 4.10 The PPS Cabinet Signal Calibration Uncertainty, abbreviated CUA in Section 8, Form 11, Sheet 2, is the combination of Calibration Uncertainty, Detector SCE 26-426 REV 0 M4 (REFERENCE SO123-XXIV-7.15)
NES&L DEPARTMENT ICCN NO) g)
"^
CALCULATION SHEET PREUM. CCN NO.
PAGE 19 of _4 4 i
CCN CONVERSION: !
Protect or DCP / FCN N/A Calc No. J-SBAC CCN NO CCN.
Subject DNatPtXOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE D/.TE REV ORIGINATOR DATE IRE DATE 8
h 0
D.McQuedo 03 19-93 E.Qumn 03 19-93
$2 4
i Sensitivity, Accuracy, and Neutron Flux Uncertainty. The resulting voltage is i0.345 V (see Section 4.2, 'High Logarithmic Power Level Setpoints' of Reference 6.8).
This uncertainty applies to the at-power calibration of the nuclear channel and other uncertainties in the nuclear detector and nuclear channel. It is taken as a design input.
The effect of the uncertainty is assessed by calculating the voltage for 100%
power, subtracting 0.345 V, and calculating the power for the resulting voltage. The calculation is:
The formulas are:
% Power = 2 x 10N-8) or, V = 8 Volts + log (% Power / 2) Volts Calculating voltage from 100% power:
V = 8 Volts + log (% Power / 2) Volts V = 8 Volts + log (100%/2) Volts = 8 Volts + 1.699 Volts V = 9.699 Volts @ 100% Power Subtracting 0.345 V:
New V = 9.699 V - 0.345 V = 9.354 V Calculating power from Voltage:
% Power = 2 x 10N-8)%
% Power = 2 x 10 (s254 83% = 2 x 22.594%
% Power = 45.189%
The difference between the two power levels is:
Difference = 100 % -45.189%
Difference = 54.811% Corresponds to Voltage Uncertainty of 0.345V As mentioned above, this uncertainty applies to the nuclear channel and its adjustment and is therefore taken as a design input.
SCE 26-426 REV 0 8/94 (REFERENCE SO123-XXIV-7.15)
NES&t. DEPARTMENT ICCM NO/
jj3 CALCULATION SticET PREuM. CCN NO.
PAGE 20 yjg,
CCN CONVERSION:
Pro'pect or DCP / FCN N/A Calc No. J-SBA E CCN NO. CCN-
[
Subject DNELtPD/ LOG POWER TRIP BYPASS
?M No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 5
0 D. McQuade 03 19-93 E.Qumn 03 19 93 N*l As used in this calculation, the value of 10.345 V is squared to produce 0.119 V2; this value is used as CUA in Section 8, Form 11, Sheet 2.
l 1
I i
SCE 2H26 REV 0 8/94 (REFFREPG S0123-XXN-7.15)
NES&L DEPARTMENT ICCN NOl y3 CALCULATION SHEET PREUM. CCN NO.
PAGE 21 of _%
CCN CONVERSION:
7 Protect or DCP / FCN N/A "alc No. J-SBA-023 CCN NO CCN-(
, Sub ect taetPo/ Loo PowtR TRP evPASS t
Sheet No.
of 5[ ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 8
c
- o. uco.a.oo ca-se-os
- e. ouinn
- o.,ts.es 1
FORM 1: LOOP / PROCESS DATA SHEET DATA REFERENCE Loop Number 2(3)JY-K099-1.-2.-3.-4 6.6 Service Description High Log Power Bypass 6.6 Technical 3.3.1, Table 3.3.1-1 6.2 Specification Upper Operational Limit 4.1E-4% Log Power Sec. 4.8, 5.4 Lower Analytical Limit 1.48E-5% Log Power Process Measurement Rod shadowing Sec. 5.2 Uncertainty (Pma)
Temperature Decalibration Azimuthal Tilt Normal Operation 100% Reactor Power G.4 Upper Limit Normal Operation 10 % Reactor Power 6.4 4
Lower Limit Applicable UFSAR CEA Withdrawal Transients 6.1 Events Low RCS Flow Cable Type N/A N/A
@r_sh Environ Only) i l
SCE 26 426 REV o &94 (REFERENCE SO123-XXIV 7.15)
=.
NES&L DEPARTMENT ICCM NO1 of {&
}
CALCULATION SHEET PREUM. CCN No.
PAGE 22 CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-
[
4 Subject DNB/LPOlt 00 POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR I DATE IRE DATEl
[
o
- o. wou.a.
os to-os
- e. ouinn os-19-os FORM 2: INSTRUMENT DATA SHEET (DEVICE 1)
DATA REFERENCE Tag Number 2(3)JY K099-1,-2,-3,-4 6.6 Manufacturer General Atomic Company 6.4 Model Number NT-4 Bistable 6.4 l
Location Control Room 6.11 Service Description High Log Power Trip 6.6 Bypass Quality Class ll 6.11 Environmental NO 6.11 Qualification input Range, Min.
OV 6.4 Input Range, Max.
10 V 6.4 Output Range, Min.
OV 6.4 Output Range, Max.
13 V 6.4 Surveillance /
S023-il-5.1 through 5.8 6.5 l
Calib. Procedure Calibration Interval 31 Days 6.5 Setting Tolerance iO.01 V 6.5 Allowance (St,)
Setting Tolerance 0.025 V 6.8 Allowance (Sto)
SCE 26-426 REV o 8/94 (REmaet #o123-XXIV-7.15)
NESSL DEPARTMENT ICCM NO/
of[%
3 CALCULATION SHEET PREW CCN NO.
PAGE 23 CCN CONVERSION:
erolect or DCP / FCN N/A Calc No. J-SBA-023 CCN NO CCN-
, Subject DN8/LPD/_ LOG POWER Trip BYPASS Sheet No.
of REV ORlWATOR DATE tRE lDATE REV ORIGINATOR DATE IRE DATE 8
0 D.McQ 03-19-93 E.Qumn 03 19-93
${h 2
FORM 3: MAKE/MODEL DATA SHEET (Device 1)
DATA REFERENCE Type Bistable 6.4 i
Manufacturer General Atomic Company 6.4 Model NT-4 6.4 Accuracy (Aa,)
i 0.5% = i0.05 V 6.4.
Drift (Da,)
- 0.5% = 0.05 V 6.4. 3.1.2 Calibration AF/AL N/A N/A Data Analycic (Dan,)
Ambient Temperature i 0.2% = 0.02 V 6.4, 3.1.5 Sensitivity (Te,)
Ambient Pressure N/A 3.1.3 Sensitivity (Pe,)
i l
Power Supply N/A 3.1.4 Sensitivity (Ps,)
Radiation N/A 3.1.1 Sensitivity (Re,)
Seismic Uncertainty N/A 6.13 (Se,)
Static Pressure N/A N/A
_ Sensitivity (Sspz)
Readability N/A N/A (Rd,)
i Reset Hysteresis (BH) 0.1 V 6.4 i
SCE 25 426 R EV J SS4 (REFER ENCE SO123-XXIV-7.1$)
I
NES&L DEPARTMENT ICCN NOl l'PAGE 3
CALCULATION SHEET PREUM. CCN NO.
N'l j
24 c. W d
CCN CONVERSION.
Project or DCP / FCN N/A Cal: No. J-SBA E CCN NO. CCN-Subject DNB/LPD/ LOG POWER Trip BYPASS Sheet No.
of i
REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 8
l 0
D. hkounde 03 19-93 E. Quinn 03 19-93
$2 4
FORM 4: ENVIRONMENTAL CONDITIONS DATA SHEET Area B6: Cabinet Area of Control Room DATA REFERENCE l
Normal Temperature 70 *F 12.5 6.1 i
Minimum, *F Table 9.4-4 3.1.6 Normal Temperature 75 *F 2.5 6.1 Maximum, *F Table 9.4-4 3.1.6 Normal Radiation
< 1.0E4 RAD TID per 40 yrs 6.3 Value, gamma Rads Table 0-1 Normal Pressure o psig 6.3 Minimum, psig Table 0-1 l
Normal Pressure O psig 6.3 Maximum, psig Table 0-1 Accident Temperature 80*F (Cabinet Area) 6.3 Maximum. *F Figure C-5 Accident Radiation
< 1*10' Rad 6.3 Value, Rads gamma Accident Radiation
< 1*10 Rad 6.3 d
Value. Rads beta Accident Pressure o psig 6.3 Maximum, psig Table 0-1 g
w SCE 26-426 REV O 8/94 (REFERENCE SO123-XXIV 7.15)
NES&L DEPARTMENT ICCM No1 g ~p CALCULATION SHEET PREUM CCN NO.
PAGE 25 of 4CL CCN CONVERSION:
Project or DCP / FCH N/A
_ Calc No. J-SBAE CCN NO. CCN-
[.
Subject DNeulPD/ LOG POWER TRP BYPASS Sheet No.
of l
REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE 1RE
- DATE, g
0 D. McQuade 03-19-93 E. Quinn 03-19-93 5.0 Methodology 5.1 This calculation will determine the instrument uncertainty and associated i
setpoints for the DNB/LPD/ LOG Power Bypass. This calculation is performed l
consistent with the requirements of SCE Design Standard, JS-123-103C, Rev O and Revision 2 for CCN N-1 (reference 6.7).
l l
The input uncertainties associated with the 10 % bistable input are identical d
to those associated with the input to the High Log Power trip. These functions receive their input from the same Excore circuits, and therefore, any uncertainties associated with the input signal will affect both functions the same way. As such, the setpoints of the 10"% bistable will consider the l
uncertainties associated with the bistable only.
5.2 Process Measurement Uncertainties The excore instruments are susceptible to decalibration due to process measurement effects. The effects to be considered are those that affect the power shape of the core (rod shadowing, radial xenon distribution, and burnup), and those that affect the number of neutrons arriving at the detectors from the core (temperature shadowing and boron shadowing of water in the reactor vessel downcomer).
In this calculation, only the power being immediately produced by the fission and delayed neutrons is assumed to produce a signal at the detectors. The effect of other neutrons associated with sources that do not reflect the instantaneously change in power level, for instance photo neutrons resulting from the decay of fission products or neutrons from neutron sources, are ignored because at the bistable setpoint, the number of these neutrons is smaller than the fission neutrons by many orders of magnitude.
The bistable setpoint is based on the power being produced by fissions because the nuclear instruments are used to control the existing core power.
Even though the calibration of the log power channels is based on core average thermal power, the setpoint is not based on core thermal power, which is a combination of the power being produced by fissions and decay heat. Decay heat can be considered a reflection of power that was produced in the past. At the bistable setpoint, core thermal power due to decay heat GCE 26426 REV 0 8/94 (REFERENCE SO123-XXIV-7.15)
NES&L DEPARTMEMT ICCN WOJ CALCULATION SHEET PREUM CCN NO.
PAGE 26 of _
CCN CONVERSION:
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of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 8
0 D. McQuade 03 19-93 E.Qumn 03 19-93
$2 4
can be expected to be a nearly constant source of heat that is several orders of magnitude greater than the power being produced by fissions.
The detectors, which are located outside the reactor vessel, produce their signals from neutrons produced mainly in the outermost assemblies. These neutrons are produced mainly by fission, and the number of fissions is directly proportional to the amount of power being produced by fissions within an assembly.
Changes in the core power shape are important because the core power shape determines the power of the outermost assemblies relative to the average core power level. The core power shape is changed by insertion of control rods (called ' rod shadowing), the radial concentration of xenon, and burnup. The number of neutrons reaching the detectors is also affected by the density of water in the downcomer of the reactor vessel. The effect of boron concentration will not be considered separately from the temperature effects because the neutrons arriving at the detectors are high-energy, whereas the high cross section of boron absorbs thermal (Iow energy) neutrons. Each effect is discussed also below.
The first three effects considered below are in conjunction with the core power shape:
5.2.1.
Rod Shadowing Core power shape is affected by the position of the control rods, and core power around the rods is depressed by insertion of control rods. If the control rods are inserted in the region of the core that supplies neutrons to detectors, there is a reduction in the number of neutrons to the detectors. This effect is called ' rod shadowing'. The nuclear detectors can be expected to be increasingly shadowed as the rods are inserted.
in practice, the rods can be expected to be nearly fully withdrawn during the calibration at full power, for zero rod shadowing. It is possible for the reactor to be significantly rodded at low power levels.
J In Revision 0 to this calculation, the expected value for rod shadowing was 13.5%, and in order to ensure conservatism, the value that is actually used was conservatively chosen to be a two-sided i23%.
The factor for rod shadowing therefore becomes:
sCE 26-426 REV 0 8.WREFERENCE SO123-XXIV-7.15)
NES&L DEPARTMENT ICCM NOJ PAGE, jt7_ of %g CALCULATION SHEET PREuM. CCN NO.
CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBAE13 CCN NO. CCN.
f Subsect DN8/LPD/ LOG POWER TRIP SYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D. McQuade 03 19-93 E.Qumn 03 19-93 D
$2 4
F oos = 123%
R 5.2.2.
Radial Xenon Power Shift The wide range instrument channels are calibrated and calibration checked at full power, with a radial power distribution that can differ from the distribution at the power leve:s where the bistable is used. This transient effect is most pronounced if the core has been at high power levels prior to a trip, and a reactor startup is timed so criticality occurs at the peak of the xenon build-in and decay curve. Startups can be expected to occur when the xenon concentration is at its peak, approximately 16 to 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> following a trip.
The radial power distribution changes because, for example, at high power before a trip the middle of the core can be operating at a higher than average power and be producing more fissions. The greater number of fissions produce.s more xenon atoms after a trip, when xenon builds-in. The greater number of xenon atoms depresses the power in the middle of the core, which shifts power to the periphery if the core is brought critical with appreciable xenon still in the core.
Conversely, the pre-trip power shape at high power can have the flux in the middle of the core depressed and result in a relatively low post-trip peripheral power shape.
A value of i10% is chosen by engineering judgement for the change in signal due to xenon redistribution at the bistable setpoint following a trip from high power.
Fxtnoy = 10%
The radial xenon power shift is independent of rods and core burn-up and depends on the basic physics of xenon build-in and decay.
5.2.3.
Core Burn-Up The wide range channels are normally calibrated once every cycle at the beginning of each cycle. The radial power shape changes from beginning to end of cycle as fuel and burnable poisons are consumed. The change due to shape has been calculated to be t10% (Section 8.2.5 of Reference 6.16).
- CE 26-426 REV 0 8/94 (REFERENCE SO123-XXIV 7.15)
NES&L DEPARTMENT ICCN NO1 j3 n,,
CALCULATION SHEET PREUM. CCN NO.
PAGE 28 of W CCN CONVERSION:
Protect or DCP / FCN N/A Calc No. J-SBA423 CCN NO. CCN-Subject DNB/LPDi00 POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D. McQuede 03-19-93 E. Quinn 03-19-93 0
$2 4
FBURNUP = 10%
Because the net effect of the changes due to rod shadowing, radial xenon power shift, and core burn-up are independent, they will be treated as the Sum of Root Sum Squared (SRSS):
Net Effecteo,,e,,c., = ( (Faoos) + (pX NON
+
BURNUP Net Effectc,,en.c., = ( (123%)2 + (t10%)2 + (110%)2 )os =
( 729% )
- Net Effeetc.,,en,ci, 27 %
=
5.2.4. Temperature Shadowing.
The neutrons from the core pass through water in the reactor vessel downcomer which attenuates and scatters some of the neutrons and thereby reduces the neutron signal at the detectors. Decreasing the temperature of the water increases the density of the water and results in fewer neutrons reaching the detectors. This effect is called ' temperature shadowing' and is an effect that has been measured.
The temperature limits for actuation of the bypass and the reset are assumed to be the analysis temperature limits for criticality at 0% power. The Reload Ground Rules for Cycle 10, Unit 2, (Reference 6.15), which reflect present and future operation of the plant, specify a Transient Analysis (TA) temperature range Tcold of 520*F to 560*F in RGR Figure 111-2 for 0 power, a range of 40*F. The new reduced operating limits for criticality, by Technical Specifications, are a Tcold of 522*F to 558'F.
Temperatures outside the limits for criticality will not be considered because the bypass is a manual operation and is operated under close observation and carefully controlled conditions. It would be operated only under Mode 2 conditions, with the reactor at very low power level.
The reset is enabled following a reactor trip. The range of normal operation following a reactor trip is also assumed to be within the limits for criticality.
The instruments could be calibrated at, for instance, the highest temperature and then used at the lowest. The maximum increase or decrease in sCE 26-426 REV O 8/94 (REFERENCE SO123 XXW-7.15)
NES&L DEPARTMENT TCCN NO1 7
"*l CALCULATION SHEET PREUM. CCN NO.
PAGE 29 o %,
j CCN CONVERSION:
j Protect or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-
/
Sub)ect DNBiPD/ LOG POWFR TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
o o+cou.a.
os.io-sa E. ownn o3.is-s3 temperature to the limits would be 40'F.
The uncertainty of the CPC cold leg instruments of i3.0*F (Section Vill, item Vlli.001 of Reference 6.15) must be added to the change of 40*F, for a total that will be taken to be i43*F.
The measured temperature shadowing effect is approximately 0.6%/*F. For i
conservatism, the temperature shadowing effect will be assumed to be 0.8 of signal / *F.
The temperature shadowing uncertainty is the temperature shadowing effect multiplied by the change in signal, or:
Tssu = 0.8% indication / *F x i43 *F Tssu = iM.4%
5.2.6 Summing The Effects The four effects listed above are independent and the sum of the effects will be taken as the SRSS:
)
Net = ((Net Effecte,e%)2 + ( Tssu f )"
Net = (( 27% ) + ( 134.4% )2 )o.s = (1912.36 % ) 5 Net = i43.7%
1 Revision 0 of this calculation used an uncertainty of 53.4%, which will be used in CCN N-1. The difference between 53.4% and i43.7% is 9.7%, a margin that is reserved in this calculation to ensure that the Process Measurement Effects are conservative and satisfies the intent of a margin of at least iO.5%
as required in the Calculation Standard (Reference 6.7, Revision 2).
5.3 Calculation of 10"% Bistable Process Measurement Effects The Net effect in Section 5.2.5 must be converted to a voltage from a percentage of full scale. The resulting voltage applies to the entire scale, at full power or at the bistable setpoint of 10"% power. There is one decade per volt for 10 decades of full scale, from 2 x 10-8% power to 2 x 102 3CE 26426 REV o 8/94 (REFERENCE SO123-XXIW7.15)
NES&L DEPARTMENT 3CCie NOl p
CALCULATION SHEET PREUM. CCN NO.
PAGE 30 of A CCN CONVERSION:
Profoct or DCP / FCN N/A Calc No. J-SBA-023 CCN NO.
CCN-Subject ONa/LPD/ LOG POWER TRIP BYPASS t
Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE E
O D. M ""-
03-19 93 E. Qwnn 03-19 93
.h
$2 4
power.
The basic equation for the log power channels is:
% Power = 2 x 10N 8)
Where V = Volts signal Rearranging: V = 8 + Log (% Power / 2)
The Voltage at 100% power is:
V oos = 8 + Log (100 / 2) = 9.699 V 3
The decalibration of 53.4% is calculated from 100%.
The percent power at the decalibration is 100% - 53.4 % = 46.6%
V 3% = 8 + Log ( 46.6 / 2) = 9.367 V The difference in voltages is:
V,,,,,,,,,,n = V,oos - V.3%
33,,,,n = 9.699 V - 9.367 V V,,,,uo,,,,, = 0.332 V decalibration Thus, the decalibration is 0.332 V, or 0.332 decade, and applies to any part of the instrument range.
5.4 Conversion of Engineering Units 5.4.1 Because the wide range excore is a logarithmic channel, the calculations will be performed in volts, and then converted to a percent power value for the log scale. In determining the allowable setpoints for this bistable, two cases were examined. For a decreasing power, the point at which the High Log Power Trip should NOT be in bypass becomes the basis. The High Log Power Trip cannot be bypassed at a power level which the low power transients are difficult to be controlled without the High Log Power Trip in place. Typically, SONGS 2/3 is considered stabilized for increasing power 3CE 26-426 REV O 8/94 (REFERENCE SO123-XXIV-7.15)
l WES&L DEPARTMENT ICCN No1 g3 CALCULATION SHEET PREUM CCN NO.
PAGE 31 of %
i CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-S BA-023 CCN NO. CCN-
[
Subject DNBAPD&OG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE 1RE DATE g
0 D. McQuade 03 19-93 E.Qumn 03-19-93 l
4 at approximately 10 % RTP.
For an increasing power, the power level at which the High Log Power Trip can be bypassed is a power level that the neutron flux level is considered to be stabilized. When evaluating an increasing signal for this function, the High Log Power Trip must also be considered. The High Log Power Trip setpoint is 0.837% power. The High Log Power Trip TLU has been subtracted again to be conservative in accounting for the High Log Power Trip bistable uncertainty. This trip function must be bypassed in order to bring the reactor to full power. The voltage used in the calculation for this power level was derived as follows:
%PWR = 2 x 10**) (Base equation for log channel)
Let (v-8) = X 0.351 = 2 x 10*
0.1755 = 10*
Log 0.1755 = X Log 10 l
X =-0.7557 If X =-0.7557, then (v-8) = -0.7557 l
l V = 7.244 volts 4
Similarly, the 10 % RTP voltage used in the calculation was derived as follows:
% PWR = 2 x 10**)
4 10 = 2 x 10*
f 5 x 10 = 10*
4 4
Log 5 x 10 = X Log 10 i
i BCE 26-426 REV 0 8/94 (REFERENCE SO123-XXIV-715) 4
NES&L DEPARTMENT ICCN NO1 Q
CALCULATION SHEET PRELIM. CCN NO.
PAGE 32 of -5Q CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBA-073 CCN NO. CCN-
[
Sutgect DNB4.PfMOG POWER TRIP BYPASS Sheet No.
of REV ORIGNATOR DATE 1RE DATE REV ORIGINATOR DATE IRE DATE 8
0 D. McQuade 03 19-93 E. Quinn 03-19-93 X =-5.301 If X =-5.301, then (v-8) = -5.301 V = 2.699 volts 4
CCN N-1 establishes an Upper Operational Limit and Lower Analytical Limit for the DNB/LPD/ Log Power Trip Bypass Setpoints as set forth in Design input 4.8.
The above derived voltages are not directly used in CCN N-1. The voltages for the new limits used in CCN N-1 are derived as follows:
% PWR = 2 x 10(d) or V = 8 + Log (%PWR/2)
For the Upper Operational Limit of 4E-4% Power -
V = 8 + Log (4E-4%/2)
V = 4.301 Volts
]
For the Lower Analytical Limit of 1.5E-5% Power -
V = 8 + Log (1.5E-5%/2)
V = 2.875 Volts 5.5 Word Processing Disclaimer
{
This document was produced using Wordperfect 5.1. All computations were performed and verified with a hand-held calculator. Wordperfect did not perform any computations in this design calculation.
BCE 26-426 REV 0 8/94 (REFERENCE SO123-XXIV.7.15)
i i
NES&L DEPARTMENT ICCN NO/
"'I CALCULATION SHEET PREuM. CCN NO.
PAGE. 33 o.1 CCN CONVERSION: /
Profect or DCP / FCN N/A Calc No. J-SBA423 CCN NO CCN-(
Sutnoct ONatPD/ LOG POWER TRIP SYPASS Sheet No.
of REV ORIGINATOR DATE 1RE DATE REV ORIGINATOR DATE IRE DATE g
o
- o. -
os. sus E. omnn os.io-os 6.0 References 6.1 SONGS 2&3 Final Safety Analysis Report (FSAR), Rev. 8, and Revision 13 i
for CCN N-1.
6.2 Unit 2 Technical Specifications (Amendment 104) and Unit 3 Technical Specifications (Amendment 95), and TS Amendments 127 and 116, respectively, for CCN N-1.
6.3 Environmental Qualification Topical Report, Design Bases Document, DBD-SO23-TR-EO, Rev. O.
6.4 Safety Channel - Operation and Maintenance Manual, Prepared for Combustion Engineering Inc. for San Onofre Nuclear Generating Station, Units 2 & 3, General Atomic Company, July 1983. SO23-941-45.
6.5 Surveillance Requirement, Nuclear Instrumentation Safety Channel; SO23-11-5.1 thru 5.8.
6.6 Excore Nuclear instrumentation System Design Bases Document; DBD-SO23-470, Rev. O, and Revision 3 for CCN N-1.
l 6.7 SCE Setpoint Methodology Standard, JS-123-103C, Rev. O, and Revision 2 for CCN N-1.
6.8 CE-NPSD-570-P Rev. 03-P, Plant Protection System Setpoint Calculation, (SO23-944-C50-0). SO23-944-C50-3 for CCN N-1.
l 6.9 1992 Design Basis Document Program Plan, Rev. 6, February 92, page B2.
6.10 Letter from U.S. NRC dated 1/12/90, NRC Inspection of SONGS Units 2/3, Report NO. 50361 and 362/89-200.
6.11 SONGS Electronic Data Base - PEDM, Verified 8-29-86.
6.12 SONGS Units 2 & 3 CPC and CEAC Data Base Listing. CE NPSD-337-P, Rev. 00-P, Dated January 1986.
ECE 26-426 REV o S/94 (REFERENCE SO123-XXN-7.15)
NES&L DEPARTMENT ICCN MO1 g3 N4 CALCULATION SHEET PRELIM. CCN NO.
PAGE 34 of 1 CCN CONVER$10N:
Project or DCP / FCN N/A Calc No. J-SBA-023 CCN NO CCN-Sutgect DN8/LPDS.OG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE tRE DATE 5
0 D. McQuade 03 19-93 E. Quinn 03-19-93 0
$2 4
6.13 Test Report, Seismic Testing of Safety Channel Electronic Chassis Type ELE 304-3000, Report NO. E-115-539, dated February 1976 6.14 SCE Nuclear Fuels Management Calculation NFM-2/3-TA-0008.
l 6.15 Unit 2 Cycle 10 Reload Ground Rules, RGR-U2-C10, Revision 0 l
6.16 Neutron Flux Level Startup Channel Removal Signal, J-SEA-023, Revision 0
1 r,CE 26-426 REV 0 BS4 (REFERENCE SO123-XXN-7.15)
NES&L DEPARTMENT ICCN NOJ CALCULATION SHEET PREuM. CCN NO.
N4 PAGE 35 ofk CCN CONVERSION:
f Propet or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-
/
Subpct DNS/LPO&OG POWER TRP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g l o
o.ucou os. ism E. ou.nn ossem 7.0 Nomenclature 7.1 Safety Functions (Reference 6.9)
Those systems, structures or topical issue functions that directly or indirectly support one or more of the following plant nuclear safety performance goals:
1)
Maintain reactor coolant pressure boundary integrity.
2)
Provide capability to shutdown the reactor and maintain the safe shutdown condition.
3)
Prevent or mitigate the consequences of accidents which could potentially result in off-site exposures comparable to 10CFR Part 100 guidelines.
The term " safety related" applies to the prevention or mitigation of the consequences of postulated accidents that could cause undue risk to the health and safety of the public. Important-to-safety relates to " plant safety".
7.2 Additional terms used in this calculation:
AV,- Allowable Value for increasing setpoint l
AV,- Allowable Value for decreasing setpoint l
CPC - Core Protection Calculator l
DNB(R) - Departure from Nucleate Boiling (Ratio) l ELFP - Effective Linear Full Power LOL - Lower Operational Limit (section 4.2) l LPD - Local Power Density l
UOL - Upper Operational Limit l
3CE 26-426 REV o 8/94 (REFERENCE 50123-X)UV-7.tS)
NES&L DEPARTMENT ICCMNOJ S ')
CALCULATION SHEET PREuM. CCN NO.
N^
PAGE 36 oT %,
CCN CONVERSION:
P,rotect or DCP / FCN N/A Cat % J-SBA@
{
CCN NO CCN-Subtect DNS/LPD/ LOG POWER TRIP BYPASS Sheet No of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
o o ucu.*
os.ie es E. ouinn os.is-es 8.0 Calculations 8.1 Design Basis of 10"% Bistable Setting The withdraw of CEAs from suberitical or low power conditions adds reactivity to the reactor core, causing both the core power level and the core heat flux to inctcase together with corresponding increases in reactor coolant temperatures and reactor coolant system (RCS) pressure. The withdraw motion of CEAs also produces a time dependent redistribution of core power. These transient variations in core thermal parameters result in the system's approach to the specified fuel design limits and RCS and secondary system pressure limits, thereby requiring the protective action of the reactor protection systems.
At subcritical and low power conditions, the normal reactor feedback mechanisms do not occur until power generation in the core is large enough to cause changes in the fuel and moderator temperatures. The reactivity insertion rate due to the CEA withdraw rate and the rod worth determines the rate of approach to the fuel design limits. Parametric analyses have indicated that the lowest initial power level of 10-8%
subcritical core condition, results in the closest and fastest approach to the fuel design limits during the CEA withdrawal transient. Initially suberitical, zero power CEA withdrawal transients are terminated by the High Log Power Trip while those initiated from a power level just above the High Log Power trip bypass of 1E-5% power are terminated by the CPC low DNBR l
(VOPT) trip or the high LPD trip. Parametric analysis has shown that at power levels above 1E-5%, reactivity feedback mechanisms prevail and l
provide a dampening effect on the severity of the transient.
The uncontrolled CEA withdrawal from subcritical conditions resulted in a power spike. The minimum DNBR calculated for this event was greater than the design limit. The peak linear heat generation rate was calculated to be 25.5 kw/ft which is in excess of the steady state acceptable fuel centerline melt limit of 21kw/ft. However, the fuel center line temperature was less than 4900*F and, thus, the fuel is not predicted to melt. Since the power increase for this transient was so fast, a power spike of over 60%
power, the instrument uncertainties on the trip bypass setpoint would not affect the results of the transient. Based on eng neering judgement, no instrument uncertainties were needed in deterrnining the bypass setpoint.
sCE 26426 REV O 8/94 (REFYRENCE SO1~3-XXN-7.15)
l NES&L DEPARTMENT ICCN EO)
CALCULATION SHEET PRELWA CCN NO.
PAGE 37 of _
CCN CONVERSION:
Protect or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-Sub ect DNEAPD4 OG POWER Trip BYPASS t
Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE "g
0 D. McQuade 0119-93 E.Qumn 03-19-93 O
g W4 2 This CCN N-1 uses a Lower Analytical Limit (LAL) of 1.48E-5% to ensure that the accident analysis limit is not exceeded. Also, the analysis considers that the DNBPJLPD trips have been inserted above 4.1E-4%
power. Although not a safety limit, the 4.1E-4% power serves as an Upper Operational Limit (UOL) when analyzing low power conditions. It further j
ensures sufficient margin for manual bypass operation.
8.2 Setpoint Selection The primary functions of the 10"% bistable setpoints are to permit a manual l
bypass of the High Log Power trip and the DNBR/LPD trip functions and to automatically reinstate these trip functions when required. In the c.ase of the High Log Power trip the bistable setpoint must meet two requirements. The setpoint for enabling the High Log Power trip must be set at a point were the protection this function provides is required to protect the reactor against CEA withdrawal transients. Parametric analysis has shown that this protection is required for CEA withdrawal transients initiated from power levels below 1E-5% power. The setpoint must also allow for l
sufficient margin between the bypass setting and the High Log Power trip setpoint to allow the operator sufficient margin to perform the manual bypass without causing an inadvertent unit trip. With the present bistable setpoint, approximately three decades of reactor power separates the bistable trip setpoint and the High Log Power trip setpoint. Experience has shown that this is sufficient margin for the operator to perform the manual bypass prior to reaching the trip setpoint.
8.2.1 Basis For Setpoint 10"' increasing
- 1. Bypass permissive, High Log Power - The bistable action permits the high log power trip to be bypassed. This function is not significant from a nuclear safety perspective since failure to bypass the high log power trip would result in a reactor trip as power was increased. It is recognized that inadvertent reactor trips present challenges to safety systems and should be avoided. This is accomplished by administrative controls and establishing the bypass setpoint below the high log power trip setpoint.
DCE 26426 REV 0 8/94 (REFERENCE SO123-XXN 7.15)
. =.
NES&L DEPARTMENT ICCM NO/
$j CALCULATION SHEET PREUM. CCN NO.
PAGE 38 of h CCN CON'ERSION:
j Project or DCP / FCN N/A Calc No. J-S BA-023 CCN NO CCN.
/
Subject DNB/LPD/ LOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 8
0 D.McQuade 03-19-93 E, Quinn 03 19 93
$2 4
- 2. Auto bypass cancel, DNBR/LPD trips and Low Reactor Flow trips -
This bistable action is safety related. If this " Auto Bypass Cancel" action fails, The safety functions (DNBR/LPD and Low Reactor Coolant Flow trips) are prevented from operating in a mode where they are credited by the accident analysis. Though the High Log Power Level trip might protect the reactor by being active in this mode (it is normally bypassed), that cannot be credited because it is not analyzed.
10"% Decreasing
- 1. Auto Bypass Cancel, High Log Power Level trip - This bistable action is safety related. If this " Auto Bypass Cancel" action fails, the safety function (High Log Power Level trip) is prevented from operating in a mode where it is credited by the accident analyses.
- 2. Bypass Permissive, DNBR/LPD and Low Reactor Coolant Flow Trips - This bistable action permits these trip functions to be bypassed. This function is not significant from a nuclear safety perspective since the failure to bypass would result in a reactor trip once the shutdown or part length CEAs were inserted or a reactor coolant pump was secured.
8.3 TLU Calculation for the High Log Power Bypass Setpoint The following forms 5-11 contain data for the High Log Power Bypass bistable. The TLU is calculated for this bistable.
SCE 26-426 REV O 8/94 (REFERENCE SO123-XXN-7.15)
NES&L DEPARTMENT ICCN NO/
N^
53 CALCULATION SHEET PREUM. CCN NO.
PAGE 39 m ga_.
CCN CONVERSION:
/
Project or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-4 Subject DNB/LPO/ LOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D. McQuade 03 19-93 E. Quinn 03 19-93 6
$2 4
' FORM 5: NORMAL CONDITIONS ENVIRONMENTAL ALLOWANCE Tag Device 1 Temp. Min.
67.5' F Temp. Max.
77.5'F Temperature i 0.2% ELFP Sensitivity Temperature i 0.2% ELFP Effect Te, SUM of Te 's
- 0.02 v n
for common location Square of 0.0004 v sum Te,2 SUM OF SQUARES, TE 0.0004 v2
=
n l
Press Min.
O psig i
Press Max.
O psig Pressure N/A Sensitivity Pressure N/A Effect Pe.,
SUM of Pe 's N/A n
for common Location Square Pe,2 N/A SUM OF SQUARES, PE =
N/A n
DCE 26-426 REV O 8/94 (REFERENCE SO123-XXIV.7.15)
NES&L DEPARTMENT ICCM NO1 53 CALCULATION SHEET PRELIM. CCN NO.
"'I PAGE 40 of %
CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBAM CCN NO. CCN-Subject DN8/LPD/ LOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
o
- o. m.o.
o>1na E. ouinn c3ina 0
y W4 2 FORM 6: ACCIDENT CONDITIONS ENVIRONMENTAu ALLOWANCE Tag Device 1 Temp. Min.
67.5'F l
Temp. Max.
77.5
- F Temperature N/A Sensitivity Temperature N/A Effect Te, SUM of Teis N/A for common location Square of N/A sums Te 2 SUM of Squares, TEg =
N/A Press. Min.
O psig Press. Max.
O psig Pressure N/A Sensitivity Pressure N/A Effect Pe, SUM of Pe/s for N/A common location Square Pe 2 N/A SUM OF SQUARES, PE, =
N/A SCE 26426 REV O 8/94 (REFERENCE SO123-XXIV-7.15)
4 WES&L DEPARTMENT ICCM Wof 53 CALCULATION SHEET PREUM CCN NO.
PAGE 41 of R N.1 CCN CONVERSION:
q Project or DCP / FCN N/A Calc No., J.SBA-023 CCN NO. CCN.
Subject DN8/LPD/ LOG POWER Trip BYPASS Sheet No.
of REV ORIGINATOR DATE tRE DATE REV ORIGINATOR DATE IRE DATE g
0 D. McQuade 03-19 93 E. Quenn 03 19-93 D
$g8 FORM 7: SElSMIC ALLOWANCE Tag Device 1 Max. Seismic N/A Acceleration 1
Seismic N/A Sensitivity Seismic N/A Effect (Se)
Square N/A SUM OF SQUARES, SEISMIC ALLOWANCE, SA =
N/A RADIATION ALLOWANCE Tag Device 1 Max. Total
<1.0E4 Rad Integrated Dose Radiation N/A Sensitivity i
Radiation N/A Effect SUM of N/A common I
locations Square N/A SUM OF SQUARES, RADIATION ALLOWANCE, RA =
N/A ECE 26-426 REV 0 8/94 (REFERENOC SO123-XXN-7.15)
NES&L DEPAR'.4 ICCN NO/
$3 CALCULATION SHE.0T PRELIM. CCN NO.
PAGE 42 of
_EG_,.
CCN CONVERSION:
Propet or DCP / FCN N/A Ci No. J-S B A-023 CCN NO. CCN-
/
Subject DNB.t.PO/ LOG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE
'h, iTE REV ll ORIGINATOR DATE IRE DATE 8
I,Mio-e3
,3 o
o.ucou.a.
os is-s3 E.oumn 1
J.
4' FORM 8: cal.lB' A. TION ALLOWANCE Tag Device 1 m,-4m input Cal Device Accuracy ll s.1.5%_ELFP. 0.05 v Output Cal Device Accuracy N/A Setting Tolerance for 0.1% ELFP Increasing Setpoint (St,)
0.01 V Decreasing Setpoint (St )
0.25% ELFP 0.025 V Sum of Squares for 0.026 to ELFP increasing Setpoint (CA,)
0.0026 V Sum of Squares for O.0313% f.LFP Decreasing Setpoint (CA.,)
0.00313 V l
SUM OF SQUARES, CAllBRATION ALLOWANCE (CA,) =
0.0026 V (increasina) 2 SUM OF SQUARES, CALIBRATION ALLOWANCE MA,) =
0.00313 V2 (decreasing)
POWER SUPPLY ALLOWANCE Tag D e vic Q, _
Min. Voltage N/A Max. Voltage N/A
\\
Power Supply Sensitivity N/A Power Supply Effect N/A SUM of common Supplies N/A,,
Square
,NL SUM OF SQUARES, POWER SUPPLY ALLOWANCE, PSA u N/A 3CE 26 426 REV o 8S4 (REFERENCE SO123-XXN 7.15)
[
5 e-
NESSL DEPARTMENT ICCM NO1 j
CALCULATION SHEET PRELIM. CCN NO.
PAGE 43 o%
CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN-
/
i Subject DNR/LPD/ LOG POWER TRIP BYPASS Sheet No of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
C D. McQuaos 03 19-93 E.Qumn 03-19-93 6
$2 4
l FORM 9: DRIFT /AF-AL ALLOWANCE Tag Device 1 Calibration 31 DAYS Interval i
Drift Rate 0.5% ELFP Drift over 10.5% ELFP Cal Interval 0.05 v Squares 0.0025 v l
SUM OF SQUARES, DRIFT ALLOWANCE, DA =
0.0025 v2 l
FORM 10: CABLE LEAKAGE ALLOWANCE 1
DescriptionNalue Reference Remarks Cable Leakage N/A l
(Ci) l l
Terminal N/A l
Block Leakage (Ti)
Penetratim N/A l
Leakege (Pi)
Splice N/A Leakage (Si)
Sealing N/A Leakage (Di) i SCE 26-426 REV 0 8/94 (REFERENCE SO123-XXN 7.15) n
..-w
NES&L DEPARTMENT ICCN t001 63 CALCULATION SHEET PRELIM. CCN NO.
PAGE 44 of _%_
CCN CONVERSION:
Project or DCP / i' N N/A Calc No. J-SBA-023 CCN NO. CCN-Subpct DNB/LP*4.oG POWER Trip BYPASS Sheet No.
of REV ORIGl*.ATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 5
0
- 0. Mcomoe 03-19-93 E.Qumn 03 19-93
$2 4
FORM 11, SHEET 1: CALCULATION
SUMMARY
(for the High Log Power Bypass Value) 1.
PROCEEE AT T AWANCE (PA) (from Fom 1)
PA = (Pma)#
0.110 V l
2.
ACCUPACY AT.T AWANCE (AA) (from Form 3)
AA = ( Aat ) 3 j
l I
AA = ( 0.05 V )
AA =
0.0025 V l
3.
MTECELLANEOUS ALLOWANCE (MA)
MA = (Mai) 2 MA = ( N/A )
i MA =
N/A 4.
ENVIRONMRMTAL ALTMWANCE (EA) (from Forms 5, 6 & 7) i 4A.
Normal Conditiens ( EA.,)
0.0004 Y
+ N/A + N/A EA,, =
0.0004 v2 i
1 sCE 26426 REV ? M4 (REFERENCE So123-XXIV 7.15)
NES&L DEPARTMENT ICCN NO1 CALCULATION SHEET PRELIM. CCN NO.
PAGE 45 o CCN CONVERSION:
{
f Project or DCP / FCN N/A Calc No J-SBA-023 CCN NO. CCN-Subject DNB/LPD/ log POWER Trip BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
O D. Mcouade 03-19-93 E.oumn 03 19-93 b{D E
FORM 11, SHEET 2: CALCULATION
SUMMARY
5.
CALISF,hTION AT.TAWANCE (CA) (from Fon es SA.
ds-red calibration allowances for an increasing setpoint,
)
i CA = AA + TS 3 2
CA:
=
0.0026 v 5B.
Squared calibration allowances for a decreasing setpoint, CA, = AA + ST.
2 CA =
0.00313 V 3
6.
PPS CABINET SIGNAL CALIBRATION UNCskTAINTY CUA = Squared log power level signal processing uncertainty { Reference 6.8; Calibration Error: RSS(A,B,C,D) = +/-0.345} (See section 4.10) l 2
CUA =
0_119 V 1
7.
DRIFT AT.TAWANCE (DA) (f rom Form 9)
DA = Squared drift allowances from Form 9 DA =
0.0025 V2 8 '.
POWER SUPPLY AT.T AWANCE (PSA) (from Form 8)
PSA = Squared power supply allowances from Form 8 l
PSA =
0
(
l i
SCE 26426 REV O 8/94 (REFERENCE So123-XXN-7.15) aw <
~ _ _ _.
l l
NES&L DEPARTMENT ICCN NO1 3
fS1 CALCULATION SHEET PXELIM. CCN NO.
PAGE 46 o __
CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBA 023 CCN NO. CCN-Subject DNBA.PO! log POWER Trip BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D. McQuade 03 19-93 E. Quinn 03 19-93 D
$2 4
FORM 11, SHEET 3: CALCULATION
SUMMARY
9.
CIRCUIT LEAKAGE AT T.nWANCE (La) (from Form 10)
La - Ci + Ti + Pi + Si + Di La =
N/A
+
N/A
+
N/A
+
N/A
+
N/A i
La =
N/A 10.
TOTAL LOOP UNCERTAINTY (TLU ) for Normal Environment Conditions 2
TLU is the total loop uncertainty for the DNB/LPD/ Log Power Trip Bypass l
2 I
NOTE:
IN DETERMINING TLU, THE CALIBRATION ALLOWANCE FOR THE DECREASING 2
SETPOINT (CAe) IS USED BECAUSE IT IS CONSERVATIVE AND ELIMINATES THE NEED TO CALCULATE A SEPARATE TLU FOR THE INCREASING AND DECREASING SETPOINTS, j
THUS SIMPLIFYING THE CALCULATION.
M
= 1 V 2
l 2 = 1/
l 0.0004
+ _Q.00313
+
0_110
+
0_0025
+ 0.119 TLU t
2 =
l o 23gog l
TLU2 =
0.485 v NOTE: ANY TERMS, OR PORTIONS OF TERMS, UNDER THE RADICAL WHICH ARE I
BIASES SHOULD BE MOVED FROM UNDER THE RADICAL AND ADDED TO THE TOTAL LOOP UNCERTAINTY.
)
SCE 26-426 REV 0 8/94 (REFERENCE So123. XXIV 7.15)
NES&L DEPARTMENT ICCN NOJ 63 CALCULATION SHEET PIELIM. CCN NO.
PAGE 47 of 1,
CCN CONVERSION:
Proiect or DCP / FCN N/A Calc No. J-SBA-023 CCN NO. CCN- [
SubpCt DNBtPDioG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D. Mcounde 03-19-93 E. ouinn 03-19-93 D
{$
FORM 11, SHEET 4: CALCULATION
SUMMARY
11.
TRID SETDOIPTP 11A.
FOR INCREASING SETPOINT:
TSpi = 1E-4% Log Power, or
]
TS,i = 8 + Log (% PWR/2 )
TS,i = 8 + Log (1E-4%/2) l l
TS,i = 3. 699 V 11B.
FOR DECREASING (RESET) SETPOINT:
Note: The decreasing setpoint is the reset of the increasing setpoint, and is based on the fixed hysteresis of the bistable.
TS
= 7.944E-5% Log Power, or g
TS,a = 8 + Log (% PWR/2 )
TS,a 8 + Log (7.944E-5%/2)
=
TS,a = 3.599 V 12.
MARGIN
- 12A, MARGIN FOR INCREASING SETPOINT:
l Margin is calculated to be the difference between the Upper Operational Limit and the Trip Setpoint t TLU.
2 MARGINi = UOL - TS, - TLU2 MARGINi = 4.212 V -
3.699 V -
0.485 V MARGIN = 0.129 V 1
ECE 26-426 REV O W94 (REFERENCE So123-XXN-7.15)
I l
l
NES&L DEPARTMENT ICCN NOJ
)
CALCULATION SHEET PRELIM. CCN NO.
PAGE 48 oA CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBAE j
CCN NO. CCN-Subject DNIVLPD/ log POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE g
0 D.McQuade 03-19-93 E. ouenn 03-19-93 D
{$
FORM 11, SHEET 5: CALCULATION
SUMMARY
12B.
MARGIN FOR DECREASING SETPOINT:
l Margin is calculated to be the difference between the Lower Analytical Limit and the Trip Setpoint 2 TLU2 minus hysteresis.
Note: BH denotes Bistable Hysteresis for Bistable Reset (from Form 3).
l MARGIN, = TS, - BH - TLU - LAL MARGIN, =
3.699 V 0.100 V -
0.495 V -
2.969 V MARGIN,=
0.245 V 12C.
MARGIN TO LOG POWER TRIP (High Log Power Trip Setpoint, Ref. 6.8)
Margin is calculated to be the difference between the High Log
}(
Power Trip Setpoint TLU and the Upper Operational Limit.
MARGIN;, = (Log Power TS, - TLU ) - UOL t
MARGIN,= ( 7.622 V -
0.379 V ) -
4.312 V]
t MARGIN;, =
2.932 V 13.
ALIDWABLE VALITE Surveillance or Calibration Procedure Reference :
6.5 Note: Values for DA and ST must be relative to the referenced l
procedures.
13A.
FOR INCREASING SETPOINT:
AV TS,i + /
t =
+ MARGIN AVi=
1.699 V + /
2 8
0.0025 V +
0.0001 V
+ 0.129 V AVi=
3.918_V or 1.51E-4% Power Avi =
3.975 V or 1.5E-4k Power rounded down l
l ECE 26-426 REV O &S4 (REFERENCE So123-XXIV.7.15) l
~
I NES&L DEPARTMENT ICCM NO1 3
CALCULATION SHEET PRELIM. CCN NO.
PAGE 49 of CCN COMVERSION:
I Protect or DCP / FCN N/A Calc No. J-S BA-021 _
CCN NO. CCN-Subject Drea.PO&OG POWER TRIP BYPASS Sheet No.
of REV ORIGINATOR DATE 1RE DATE REV ORIGINATOR DATE 1RE DATE E
0 D.McQuade 03-19-93 E.Quirm 03 19-93 st t 1
FORM 13, SHEET 6: CAL Q TION
SUMMARY
13B.
FOR DECREASING SETPOINT:
AV. = TS.. - BH - /
MARGIN AV =
3.699 V - 0.1 V -
v' 2
2 O 0025 V +
0.000625 V
- 0.245 V i
AV = _2_/21 V or 3.972E-51 Power l
o Av. = M1V or 4E-5% Power rounded up l
a
)
I l
l i
3CE 26-426 REV 0 8/94 (REFERENCE SO123-XXN-7.15)
NE::&L DEPARTMENT ICCM NO3 2
M-1 CALCULATION SHEET PRELIM. CCN NO.
PAGE 50 of _\\
CCN CONVERSION:
Project or DCP / FCN N/A Calc No. J-SBAE CCN NO. CCN-
/
Subpct DNB/LPD/ LOG POWER Trip BYPAf S Sheet No.
of REV ORIGINATOR DATE IRE DATE REV ORIGINATOR DATE IRE DATE 8
0 D. McQuade 03-19-93 f.,Qumn 03-19-93 D
f Simplified Block Diagram FIGURE 1 NI LOG CHANNEL i
NI LOG CHANNEL 1
i COUNT l RATE i
~
PPSMI LOG
/
PWR TRIP l
q PREAMP LPDOBNMI p
p gg CETECTOR
{
LOG BYPASS
,0 "O
ASSEMBLY l
{
10E 4%
l i
l
- CE 26-426 REV O 8/94 (REFERENCE SO123-XXIV-7.15) l
Si d 53 cw/
Attachment A Pagel/2 j
DNBR AND LPD PENALTT FACTOR LEAST
- DIMENSIONLESS SIGNIFICANT BITS FOR Sci.I TTPES 0 AND 1 DLSB(1-2) 1 2 329 0.0078125 0.0625 LLSB(1-2 ) 1 2 331 0.03125 0.25 RPC FIAG TIMER SETPOINT IN CPC
- SECOND (ADDRESSABLE CONSTANT)
TCBSP 1
1 333 0.0 CPCB EXECUTION TIME
- 7COND DTB
'i 1 334 0.1
!XIAT TIME DI CChiPARING BOTH CEACS FOR RFCS
- SP.COND TBOTH 1
1 335 0.5 PUMP DEPENDENT FILTER COEFFICIENTS FOR
- PEP.CENZ PoliER DYNAMIC THEINAL PoliER CAI4ULATION
/ DEGREE F
'APD(1-6) 1 6 382 0.0 0.0 0.0 0.0 0.0 0.0 APD( 7-9 )
1 3 388 0.0 0.0 0.0 I
SIGNAL BIAS FACTOR
- COUNTS OFFSTTC 1
1 397 200.0 0FFSTIE 1
1 398 200.0 f
0FFSTFE 1
1 399 0.0 d
0FFSTD 1
1 400 0.0 MODULE 2-COLD LF.G TEMPERATURE. FILTER COEFFICIENTS
- DIMENSIONLESS A'. '41F 2 410 -3.1567 3.1867 A.3F,A28 i
2 412 0.9700 -0.3924 A15,A3S 1
2 414 0.4350 0.9574 TEMPERATIRE SEADOWING FACTOR COEFFICIENIS :, IEG F**-1 C1 C2 1
2 416 0.0015 0.0080 ERECE ON MAIIMtBf COLD-IZG TEMFERATURE
- DEGREE F TCERE 1
1 418 0.0 ERROR, ON MINIMIBf COLD-IZG TEMPERATURE
- DEGREE F TCHER 1
1 419 0.0 NEITIRON FLUE-TO-1BERMAL POWER CALIB CO STANT (ADDRESSABLE CONSTANT)
- DIMENSIONLESS
~
KCAL i
1 420 I J ~~~~ ~~~
TEMPERATURE SHADOWING REFERENCE TEMPERTURE : DEGREE F (ADDRESSABLE CONSTANT)
TCREF 1
1 421 557.0
'{
CE NPSD-337-P REVISION 00-P PAGE 14
$ Of $$
1 6CHJ J-SBA-023 l
PCCN /N ; Attuhment A Page 24 i
i ii MODULE 4 t
PART LENGTH ROD ACTIVE LENGTH
- PERCENI 0F CORE HEIGHT PLROD 1
1 900 50.0 l
I NUMBER OF COLUMNS IN THE l'CS AND FPR TABLES: DDiENSIONESS NCOL 1
1 901 3.0 1
i I
NUMBER OF CEA REGULATING GEOUPS
- DDfENSIONLESS NREO 1
1 902 6.
I CONSTANT TO DEFINE PARTI' TION OF T"E
- DDfENSIONLESS i
1 903 2.
MULTIPLIERS FOR THE FPR PLANAR RADIALS
- DDfENSIONLESS
}
TABIZ (ADDRESSABLE CONSTANI)
ARM 1-ARMS 1 5 905 1.0 1.0 1.0 1.0 1.0 MULTIPLIERS FOR THE FCS SEADOWING FACTORS : DDENSIONLESS i
TABLE (ADDEASSABLE CONSTANT)
AM2-AM 5 1 4 912 1.0 1.0 1.0 1.0 1
=
CEA SHADOWING FACTORS
- DDfENSIONLESS i
-)
UNRODIED - PL101 PL2 - SB7tDOWN UNRODDED h
REG.6 l
REG.6+5 REG.6+5%
I; REG.6+5 M+3 i
REG. 6+5M+3+2 i
REG.6+5M+3+2+1
- FCS(1-3) 1 3 918 1.00 1.05 1.00 (4-6) 1 3 921 1.075 1.135 1.00 (7-9) 1 3 924 1.00 1.00 1.00 (10-12') 1 3 927 1.00 1.00 1.00 (13-15) 1 3 930 1.00 1.00 1.00 j
(16-18) 1 3 933 1.00 1.00 1.00 i
(19-21) 1 3 936 1.00 1.00 1.00 1
1 i
~
i i
I
(\\,
CE NPSD-337-P REVISION 00-P PAGE 24
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J-ssA -02 3
[84] From: DICK BOCKHORST 3/18/93 1:05PM (852 bytes: 13 in)
M MM LS I e To: JOHN W O'BRIEN
Subject:
Criticality point
. Fr(,um:................................ Forwarded-----------------------------5 MIKE MCDEVITT at AWS3 3/18/93 10:48AM (704 bytes: 13 in) lTo:. DICK BOCKHORST at MESA cc: DAVID RAMENDICK, MIKE MCDEVITT
Subject:
Criticality point
............................... Me s s a g e C on t e n t s - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
l
- Dick, l
l l
In response to your question regarding the point where we go critical, the answer is that we typically go critical no higher than 1 x 10-5 %
power.
There are variables which cause this to change from one l
startup to the next, but as a rule we do not expect criticality l
comming above 1x10-5 percent power.
L I have confirmed this with Dave Ramendick.
Mike Mcdevitt i
i i
O
[
(,
s 4
1 1
- -..,