ML20104B157
| ML20104B157 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/09/1992 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML20104B156 | List: |
| References | |
| NUDOCS 9209150013 | |
| Download: ML20104B157 (14) | |
Text
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r UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Application of-SOUTHERN CALIFORNIA )
EDIS0N COMPANY, U E , for a Class 103 ) Docket No. 50 362 License to Acquire, Possess, and Use )
a Utilization Facility as Part of ) Amendment Application Unit No. J of the San Onofre Nuclear ) No. 102 Generating Station )
SOUTHERN CAllFORNIA EDIS0N COMPANY, H R. pursuant to 10 CFR 50.90, hereby submit Amendment App Heation No. 102.
This amendment application consists of Proposed Change Number (PCN) 359 to ,
Facility Operating License No. NPF-15. PCN-359 is a request to revise San -
Onofre Unit 3 Technical Specification (TS) 3/4.4.8.1. " Pressure-Temperature --
Limits," TS 3.4.8.3.1, " Overpressure Protection Systems RCS Temperature 5302*F," and TS 3.4.8.3.2, " Overpressure Protection Systems-RCS Temperature
>302*F." The proposed change will revise the Reactor Coolant System (RCS)
Pressure-Temperature (P-T) limit curves and the Low Temperature Overpressure Protection (LTOP) enable temperatures to be effective until 8 effective full power years (EFPY) of operation, i
l l
9209150013 920909 FDR ADOCK 05000362 P PDR
_ a_.. - .-..m_._.._.._..a -
i i Subscribed on this 9#4 day of JCrrEMout 1992.
Respectfully subn.itted, SOUTHERN CAllf0RNIA EDISON COMPANY By: >
' Harold B. Ray Senior Vice Pres d t i
State of California County On 9 /9 /92of _p@uc L before me, 3444o M. he c4erW/MT44 /,"dbC-
- persorialli appeared # Meg 1> s. 4 4 y , personally known to me i to be the person whose name is subscribed to the within instrument and acknowledged to me that he executed the same in his authorized capacity, and.
- that by his signature on the instrument the person, or the entity upon behalf i, of which the person acted, executed the instrument.
WITNESS my hand and official seal. _ _ _ _ _ ___ _ _ _
i Signature M *Al s d. N ' U k WGAYAAWC CArW
~/ NWey Puhte Cedhrnio ORAMGE COUNTY o Mr OswNeon ertes t thunh 31,1996 James A. Becletto Attorney for Southern
, California Edison Company 1 NY By: A. N . 4b W N{a s A. Beotetto \
r f
DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CHANGE !!PF-15-359 This is a request to revise Technical Specifications 3/4.4.8.1, " Pressure-Temperature Limits," 3.4.8.3.1, " Overpressure Protection Systems-RCS :
Temperature 5302*F," and 3.4.8.3.2, " Overpressure Protection Systems-RCS !
4 Temperature >302*F," and associated Bases for San Onofro Unit 3. ;
Existina Saecifications Attactment A - Unit 3 Technical Specifications and Bases Proposed SoecificatJ. pas s
Attachment B - Unit 3 Technical Specifications and Bases k
DESCRIPTION Technicai Specification (TS) 3/4.4.8.1, " Pressure Temperature Limits," TS 3.4.8.3.1, " Overpressure Protection Systems-RCS Temperature-5302*F," and .
3.4.8.3.2, " Overpressure Protection Systems-RCS Temperature >302*F," provide the limiting conditions for operation, actions, and surveillance _ requirements :
for tFe Reactor Coolant System'(RCS) overpresvare protection systems.
The proposed chance revises TSs 3/4.4.8.1 and associated-Bases based on 1)-the test results and analysis of ~the first_ irradiated surveillance: capsule from >
San Onofre Unit 3, and 2) updated surveillance capsule material properties evaluated in-response to Generic Letter (GL)-92-01, Revisionsi , " Reactor Vessel Structural Integrity, 10 CFR 50.54(f)." ;The Unit 3 surveillance
- capsule was removed in-May 1990 after 4.33 Ef fective full- Power Years '(EFPY)-
of operation. The proposed change revises existing Figures 3.4;2, 3.4-3, 3.4-4, and 3.4-5 and adds new figures 3.4-6 and 3.4-7 for Remote Shutdown cooldown <
l operation. These'two-new figures account for the difference _in Total loop Uncertainties (TLUs) for pressure between shutdown instruments on'the Remote Shutdown panels and shutdown instruments in the Control Room. The TLUs for temperature for both the Remote Shutdown instruments.and the Control Room: ,
shutdown instrument; re ident" cal.
The proposed change also revises the Shutdown Cooling System (SOCS) .
OPERABILITY temperature in_TSs-3.4.8.3.1 and 3.4.8.3.2 for RCS. overpressure' .o
- prctection -based on:thet Low Temperature Overpressure Protection -(LTOP) range in TS Table 0.4-3. This-SDCS Relief Valve (LTOP)-0PERABILITY7 temperature is based on4 the methodology recommended- by NUREG-0800, Branch Technical Position RSB.5-2, Revision.1, "Overpressurization Protection'of Pressurized Water Reactors While Operating at Low Temperatures ~" .
l The proposed pressure temperature (P-T) limit curves and LTOP OPERABILITY ;
L temperature shall- be effective'until-8 EFPY of plant operation.. The specific- -
L changes to'the above-TSs are as follows:
l u
j'
-1.
L -
o
-.-.;e_~-.,,..~.,-.v,~+,,.., , o.,., . .,-.,,u,-.,n_..n.,-.,,,. n n.,w_,~ ..,---n .,.,_,.,,,e.,,,- , , . . , --,..w;,.,,,
TS INDEX
- 1. INDEX Page V, Section 3/4.4.0 - RCS temperctures changed from 5302*F to 5265*F, and from >302*F to >265af.
- 2. INDEX Page XVil:
- NORMAL OPERATION" to the title of this Figure.
- b. Figure 3.4 Replace "C00LDOWN" with " SONGS 3," change
" LIMITATIONS" to " LIMITS, replace "0-5 YEARS" with " MAXIMUM ALLOWABLE HEATUP RATES-(8 EFPY)," and add " NORMAL OPERATION" to the title of this Figure,
- c. Figure 3.4 Add " SONGS 3 COOLDOWN" before "RCS," change "4-8 EFPY" is changed to "8 EFPY," and add " NORMAL-0PERATION" to the title of this Figure. ,
"(8 EFPY)," and add " NORMAL OPERATION" to the title of this Figure.
- e. Add " Figure 3.4 6 SONGS 3 COOLDOWN RCS PRESSURE / TEMPERATURE LIMITATIONS.FOR 8 EFPY -REMOTE 3HUIDOWN OPERATION." This figure is proposed to be located on Page 3/4 4-31b.
- f. Add " Figure 3.4-7 SONGS 3 RCS PRESSURE / TEMPERATURE LIMITS MAXIMUM ALLOWABLE C00LDOWN RATES (8 EFPY) REMOTE SHUTDOWN OPERATION."
This Figure is proposed to be located on Page 3/4 4-31c.
- g. Relocate Index Figures 5.6-1, " UNITS 2 - AND 3 FUEL MINIMUM-BURNUP VS. INITIAL ENRICHMENT FOR-REGION 11 RACKS," 5.6-2, " UNIT 1 FUEL MINIMUM BURNUP VS. INITIAL ENRICHMENT FOR REGION 11 RACKS," and 5.6-3, " FUEL STORAGE PATTERNS FOR REGION 11 RACK' from XVll to Page XVila.
- 3. INDEX Page XVila - This page.now includes Index Figures 5.6-1, 5.6-2, and 5.6-3 as discussed in. Item 2.g above.
TS 3.4.8.1 The proposed change revises the existing P-T limits in Figures 3.4-2 and 3.4-4 based on the fluence at 8 EFPY. The proposed change also revises the LTOP enable temperatures in Table 3.4-3. The specific changes are as follows:
- 1. Add new Figures 3.4-6 and 3.4-7 to the LCO.. These new Figures provide P-T limits for Remote Shutdown cooldown operation.
- 2. Increase the required.RCS cold leg temperature from 153*F to 180*F to.
permit the maximum heatup rate of 60*F/hr in TS 3.4.8.1.a.
2
- 3. Increase the RCS cold leg temperature from 126"F to 175*F to permit the maximum cooldown rate of 100*F/hr in TS 3.4.8.1.b.
- 4. Delete the LIMITING CONDITION FOR OPERATION heading on page 3/4 4-28a.
This existing Leading is deleted because it is inappropriate for the Surveillance Requiremants section of the TS. This cl.ange is editorial. ,
- 5. In Surveillance Requitement 4.4.8.1.2 the changes are:
- a. In the second sentence of the first paragraph, replace 'and 3.4-3" after " Figures 3.4-2r with "through 3.4-7." This change makes the TS reflect the correct Figures.
- b. In the third senten,:e of the same paragr?.ph, replace " based on the greate. of the following:" after "Teniperature" with 'in accordance with Regulatory Guide 1.99, Revision 2, " Radiation Embrittlement of Reacts.r Vessel Materials," M1y 1988.' -
- c. Delete SR 4.4.8.1.2.a and 4.4.8.1.2.b.
The existing SR 4.4.8.1.2 specifies that 1) surveillance data should be used to 1) recalculate the Adjusted Reference Temperature (ART) and update the RCS pressure-temperature limit curves, and 2) the ART should be recalculated based on the greater of the actual shift _(ART) of the limiting plate determined from surveillance data or the predicted shif t (ART) of the limiting weld determinc.d from Regulatory Guide 1.99 Revision 2.
The existing TS 4.4.8.1.2 dots not accurately reflect the guidance of Regulatory Guide 1.99 Revision 2 on the use of surveillance data to determine the ART. P39ulatory Guide 1.99, Revision 2 specifies that when two or more credible surveillance data sets become available, the ART should be calet. lated based on the surveillance data and the Regulatory Guide 1.99 methodology and the greater of the two ART values from this calculation should be used. The method of calculating ART applies to both vessel beltline plates and welds as long as the surveillance data are credible (as defined in Regulatory Guide 1.99, Revision 2). Hence, the revised TS 4.4.8.1.2 simply specifies that the surveillance capsule analysis results will be used-to update the RCS pressure-temperature limits in accordance with Regulatory Guide 1.99, Revision 2. This change clarifies that no deviations from this guidance are intended.
- 6. Revise Figures 3.4-2 through 3.4-5 based on-the test results and analysis of the Unit 3 surveillance capsule withdrawn in May 1990 and updated material properties evaluated in response to GL 92 01,
- i. Add "HEATUP," change "4-8" to "8,". and add " Normal Operation" in the title so that it reads " SONGS 3 HEATdp RCS 3
'l
i 4
l 2
PRESSURE / TEMPERATURE LIMITATIONS FOR 8 EFPY Normal Operation."
l 11. Inservice Test Curve - Change the Lowest Service Temperature
- (LST) from 202*F to 208'F. The allowable inservice test RCS i pressure at the LST is decressed from 1650 psia at 202*F to 1054 psia at 208'F.
! tii. Heatup Curve - Revise the 60*F/HR heatup curve based on the revised calculations. For the portion of the curve above the LTOP alignment temperature, all segments of the curve 3 have shifted to the right, i.e., toward a lower allr~ed i
pressure at a given temperature.
iv. Core Critical Curve - Revise the curve corresponding to the change in the 60*F/HR heatup curve (i.e., 40*F above and
> parallel to the Heatup Curve). Change the minimum indicated
] RCS temperature from 256*F to 248'F, which is equal to the
- LST of 208'F + 40*F shift above the 60*F/HR heatup curve.
J. Change the " Indicated Pressurizer Pressure (Psia)" scale in Figure 3.4-2 to start at "15 )sia" instead of "0" psia. The existing Figure 3.4-2 shows tie 86*F Minimum Boltup i Temperature-(MBT) line intersecting the "0" psia line. This
- configuration also applies to Figure 3.4-4.
3' Th6 proposed Figures 3.4-2 and 3.4-4 correct the existing TS which shews the 862F MBT line intersecting the "0" psia
- line._ The MBT should intersect the pressure which is equivalent to atmospheric pressure (15 psia) that exists in
' the RCS when the head is detensioned. Therefore, the
" Indicated Pressurizer Pressure (Psia)" scale is changed to commence at "15 psia" instead of "O psia."
- b. Figure 3.4-3: SONGS 3 RCS PRESSURE / TEMPERATURE LIMITS MAXIMUM ALLOWABLE HEATUP RATES-(4-8 EFPY)
- i. Change "(4-8 EFPY)" to "(8 EFPY)," and add " Normal Operation" in.the title to differentiate this curve from the
, remote shutdown allowable heatup rate curve, ii. Decrease the maximum heat-up rate from 22'F/HR to 14*F/HR at the indicated RCS boltup temperature of 86*F.
iii. Increase the required RCS cold leg temperature from 153*F to .
180*F to permit-the maximum heatup rate of 60*F/hr.
- i. Add "C00LDOWN," change "4-8 EFPY" to "8 'iFPY," and add
" Normal Operation" to the title.so that it reads " SONGS 3 4
'T
COOLDOWN RCS PRESSURE / TEMPERATURE LIMITAT10llS FOR 8 EfPY.
Normal Operation."
- 11. Change the LST from 202*F to 208PF, The allowable inservice test RCS pressure at the LST is decreased from 1200 psia at 202*F to 680 psia at the new LST of 208'F.
iii. Change the pressure scale to start at 15 psia. The existing Figure 3.4 4 shows the pressure scale starting at 0 psia.
iv. Increase the required RCS cold leg temperature from 126'F to 175'F to permit the maximum cooldown rate of 100*F/HR.
- d. Figure 3.4-5: SONGS 3 RCS PRESSURE / TEMPERATURE LIMITS MAXIMUM ALLOWABLE COOLDOWN RATES (4-8 EFPY)
- 1. Change "(4-8 EFPY)" to "(8 EFPY)," and add " Normal Operation" in the title to read " SONGS 3 RCS PRESSURE / TEMPERATURE LIMITS MAXIMUM ALLOWABLE C00LOOWN RATES (8 EFPY), Normal Operation.""
ii. Decrease the inaximum allowable cooldown rate from ,0af/HR to 7.8'F/HR at the 86*F minimum boltup tomperature with the -
head tensioned.
iii. Increase the required RCS cold leg temperature from 126af to 175af to permit the maximum cooldown rate of 100*F/HR.
- 7. Add Figure 3.4-6, " SONGS 3 000LDOWN RCS PRESSURE / TEMPERATURE LIMITATIONS FOR 8 EFPY, Remote Shutdown Operation," and Figure 3.4-7, " SONGS 3 RCS PRESSURE / TEMPERATURE LIMITS MAXIMUM ALLOWABLE C00LDOWN RATES (8 EFPY),
Remote Shutdown Operation."
These two new curves that are added to TS 3.4.8.1 are the result of an analysis which determined that the TLUs for pressure for the Remote Shutdown panel instruments are higher than the TLus for pressure for the Control Room shutdown instruments. T!.ese new curves will account for the Remote Shutdown instrument TLUs. The TLUs for temperature for both the Remote Shutdown instruments and the Control Room shutdown instruments are identical.
- 8. .le 3.4-3: Low Temperature RCS Overpressure Protection Range
- a. Decrease the Low Temperature Overpressure Protection (LTOP)
OPERABILITY temperatures from 302*F to 265'F for heatup and from 267*F to 249'F for cooldown during normal operations,
- b. Add LTOP OPERABILITY temperature of 249af for remote shutdown cooldown operation. Indicate heatup operations are not performed from the Remote Shutdown panels.
5
JS 3.4.8.3 1 Revise the LTOP OPERABILITY temperature in the title from 5302*F to 5265'F.
TS 3.4.8.3.2 Revise the LTOP OPERABILITY temperature in the title from >302*F to >265'F.
BASES to TS 3/4.4.8 Revise the associated Bases to TS 3/4.4.8, " Pressure / Temperature Limits," to document the basis for these TS changes and update Table B 3/4.4-1, " Reactor Vessel Toughness" based on material properties evaluated in the July 6, 1992 SCE respo,ise to GL 92-01, Revision 1. The revisions to TS 3/4.4.8 Bases are as follows:
- 1. On Page B 3/4 4 7 In the first sentence of the first paragraph, add "for normal operation" after " limit curves," change " Figures 3.4-2 and-3.4-3" in the parenthesis to " Figures 3.4-2 and 3.4-4," and add "and the cooldown limit curve for remote shutdown operation (Figure 3.4-6)" after the parenthatical "(Figures 3.4-2 and 3.4-4)." Add a new second sentence to the first paragraph to read "The limit curves for Remote Shutdown operation are determined using the Total Loop Uncertainties (TLUs) for temperature and pressure for the Remote Shutdown Panel instruments in which the pressure TLUs are higher than those for the Control Room shutdown instruments." In the last sentence of the first paragraph, change "3.4 3" to "3.4-4" and add "for normal operation and Figure 3.4-6 for Remote Shutdown operation" after "3.4-4."
In the first sentence of the second paragraph, change "have been" to "w6re," and add " prior to reactor startup" after " tested." In the second sentence, add "ano the updates in response to Generic letter 92-01, " Reactor Vessel Structural Integrity,-Revision 1" after "these tests." In the fourth sentence, change " Table 5.2-5" to Table "5.2-6."
In the fifth sentence, add " limit curve (Figure 3.4-2)" after "heatup,"
"the" before "cooldown," and replace " Figures 3.4-2 and 3.4-3" with
" Figures 3.4-4 and 3.4-6."
In the first sentence of the third paragraph, add "50" after "10 CFR."
This change makes the Unit 3 consistent with Unit 2.
In the last paragraph, change " Figures" to " Figure," ud delete 3.4-3.
Neither the existing nor the proposed Figure 3.4-3 show the criticality or the inservice leak and hydrostatic testing pressure-temperature limit lines. This change is made to. correct the description of the reference.
-2. Add a new Page B 3/4 4-7a for the text overflow from Page B 3/4 4-7 which resulted from the above changes. The changes.to the-existing text i in this page are:
4 6
?
l.. the second sentence of the first paragraph of the new page, change
" Figures 3.4-2 and 3.4-3" to " Figures 3.4-2, 3.4-4, and 3.4 6." Add a new third paragraph to read: The Low Temperature Overpressure Protection (LTOP) enable temperatures are based upon the recommendations of NUREG- ,
0800 3 ranch Technical Position (BTP) RSB 5-2, Revision 1, 1 "0verpressurization Protection of Pressurized Water Reactors While j
- Operating at Low Temperatures." BTP RSB 5-2, Revision 1 defines the j enable temperature as "the water temperature correspondi q to a metal '
temperature of at least RT + 90*F at the beltline location (1/4t or 3/4t) that is controlling ,in the Appendix G limit calculations."
4 ;
- 3. On Page B3/4 4-8, Table 83/4.4-1, " Reactor Vessel Toughness," the l changes are:
l i in Rows 4, 5, and 6 under the " Temperature of Charpy V-Notch 9 30 ft-lb" column, change "32" to "40," "36" to "40, and "32" to "40,"
- respectively. Under the " Temperature of Charpy V-Notch 9 50 ft-lb"
- column, change "62" to "70," "64" to "70," and "100" to "80,"
- respectively. Under the " Minimum Upper Shelf CV energy for Longitudinal Direction-f t lb" column, change "115" to "118," "110" to "116," and "90"
- to "92," respectively, in Row 7 under the " Drop Weight Results" column, change "-20" to "-10."
In Rows 7 and 9 under the " Temperature of Charpy V-Notch 9 30 ft-lb" column, change "56" to "110" and "44" to "6U," respectively. In Rows 7
- and 8 under the " Temperature of Charpy V-Notch 9 50 ft-lb" column,
- change "100" to "135" and "66" to "70," respectively.
l l In Rows 7, 8, and 9 under the " Minimum Upper Shelf Cv energy for Longitudinal Direction-ft lb" column, change "95" to "94," "113"-to "115," and "101" to "105," respectively.
BASIS FOR AND ACCEPTABILITY OF THE RE0 VEST i The new Unit 3 P-T limits in this proposed change were found_to be more i restrictive than what is currently being used at Unit 3 based on 1) the test results and analysis of the Unit 3 surveillance capsule withdrawn after 4.33 EFPY, and 2) updated material properties in our response to the March 6,'1992, i Generic Letter 92-01, Revision 1, " Reactor Vessel Structural Integrity,10 CFR 50.54(f)." Therefore, Unit-3 administrative procedures will_ be revised to require use of the new P-T limits in this license amendment request.
1 The existing Unit 3 TS RCS P-T limits were ' calculated using the fluence for 8 EFPY which were based upon the test results and.cnalysis of the first surveillance capsule withdrawn from Unit'2 in September 1987 after 2.85 EFPY, The existing LTOP enable temperatures (302*F for heatup and 267af for cooldown) were-calculated in accordance with Branch Technical Position (BTP)
RSB 5-2 Revision 0, "0verpressurization Protection of Pressurized Water Reactors While Operating at Low Temperatures," based upon 10 CFR 50 Appendix G limits at an RCS pressure equal to _the pressurizer safety valve. setpoint, i.e., P500 psia.
7 l
The proposed Unit 3 P-T limits were calculated using 1) the fluence for 8 EFPY from the test results and analysis of the first surveillance capsule withdrawn from Unit 3 in May 1990 after 4.33 EFPY, and 2) updated material properties evaluated in response to GL 92-01, Revision 1. The proposed Unit 3 P-T limits on the RCS for normal heatup and cooldown, inservice tests, and remote shutdown cooldown are valid through 8 EFPY because the limits conform to the requirements of Appendix G and H to 10 CFR Part 50. The Unit 3 surveillance program also conforms to the requirements of A)pendix H to 10 CFR 50.
Therefore, these P-T limit changes are accepta)1e.
The proposed LTOP enable temperatures were calculated in accordance with BTP RSB 5-2, Revision 1. BTP RSB 5-2, Revision 1 defines the LTOP enable temperature as "the water temperature corresponding to a metal temperature of at least RT g 90*F at the beltline location (1/4t or 3/4t) that is controllingIn+theAppendixGlimitcalculations." This calculational basis changes the LTOP alignment temperature from 302*F to 265'F. Changing the RCS temperature at which LTOP must be aligned from 302*F to 26PF would not change the results of the most limiting energy addition transient which is driven by the differential temperature between the RCS and the steam generator rather than the RCS initial energy. The energy addition transient analysis accounts for a Reactor Coolant Pump (RCP) start with a temperature difference of 100*F between the RCS and the steam generator. Lowering the LTOP enable temperature would not change the existing 100*F differential RCP start limitations in TSs 3.4.1.3, " Hot Shutdown ." and 3.4.1.4.1, " Cold Shutdown-Loops Filled."
Therefore, the oroposed TS for the LTOP system is bounded by the original analysis and, as such, the LTOP change is acceptable.
This proposed chance is consistent with design assumptions for RCS pressure-temperature ocarational requirements, satisfies the stress limits for cyclic operations, and complies with the requirements of 10 CFR 50 Appendix G.
DISCUSSION The maximum allowable Reactor Coolant System (RCS) pressure at any temperature is based upon the stress limitations for brittle fracture. TS 3/4.4.8.1,
" Reactor Coolant System-Pressure Temperature Limits," provides operational constraints in all modes of reactor operation to ensure that the most stress limiting location in the reactor vessel is not susceptible to brittle failure as a consequence of reactor operations. . The neutron-induced embrittlement of the reactor vessel wall also affects the temperature below which '.uw-Temperature Overpressure Protection (LTOP) is required. LTOP is provided by the Shutdown Cooling System (SDCS) Relief Valve. The SDCS Relief Valve must be aligned below the specified temperature to provide. assurance that the reactor vessel wall will be operated in the ductile region in accordance with 10 CFR 50 Appendix G during both normal operation and overpressurization.
events due to equipment malfunction or operator error. The existing TSs require alignment of the SDCS relief valve below the temperature corresponding to the-P-T curve pressurizer relief valve setpoint of 2500 psia.
1 The existing Unit 3 TS RCS P-T limit curves in TS 3/4.4.8, Figures 3.4-2 and
/
3.4-4, were originally valid.until 8 EFPY at an Adjusted Reference Temperature 8
.J
(ART)) of 92.4*F at the controlling 1/4t vessel location based on the fluence and test results from the Unit 2 surveillance capsule specimen withdrawn after 2.85 EFPY of operation. The existing LTOP enable temperatures are 302*F for heatup and 267'F for cooldown. These temperatures correspond to the allowable temperatures at tb9 pressurizer safety valve setpoint, i.e., 2500 psia, on the 60*F/hr TS heatup and cooldown curves, respectively.
The proposed Unit 3 P-T limit curves in TS 3/4.4.8, figures 3.4 2, 3.4-4, and 3.4-6 are valid unti; 8 EFPY with an ART of 141.4*F at the controlling 1/4t vessel location. This 141.4*F ART was based on the updated fluence projections from the Westinghouse Report WCAP-12920, " Analysis of the Southern California Edison Company San Onofre Unit 3 Reactor Vessel Surveillance Capsule Removed from the 97* Location," March 1991, and from updated material propertias evaluated in our response to GL 92-01, Revision 1. The proposed change will revise the existing Unit 3 P-T limits for heatup and cooldown in Figures 3.4-2 and 3.4 4. The proposed change also adds P-T limits for "-nte Shutdown cooldown operation (Figure 3.4-6). Figure 3.4-6 incorporate difference in TLUs for pressure between shutdown instruments on the A.. .e Shutdown panel and those shutdown instruments in the Control Room. The TLUs for temperature for both t'io Retrote Shutdown instruments and the Control Room shutdown instruments are identical.
The proposed amendment changes the LTCP enable temperatures from 302*F to 265*F for heatup and 267*F to 249'F for cooldown during normal operations, and provides an LTOP enable temperature of 249'F for Remote Shutdown operation.
These proposed LTOP enable temperatures are based upon the recommendations of NI' REC-800 BTP RSB 5 2, Revision 1. These proposed LTOP temperatures also represent the most limiting enable temperatures for normal heatup, normal cooldown, and emote shutdown cooldown operations. Below these LTOP enable temperatures, the SDCS Relief Valve must be aligned during heatup operations and cooldown operations from either the Remote Shutdown panels or the Control Room.
The Minimum Boltup Temperature (MBT), which is used for administrative control, remains at 86*F as presently indicated in TS 3.4.8.1.d. The flux seen in the reactor vessel flange and adjacent regions results in a negligible RTm shift. Therefore, the MBT does not change with time.
The effect of the reactor closure flange on P-T limits has been analyzed and determined not to impact the P-T limits. The material correlations in the analysis were based on copper and nickel content in accordance with Regulatory Guide 1.99, Revision 2 " Radiation Embrittlement of Reactor Vessel Materials,"
May 1988.
1 Allowable temperatures for various heatup and cooldown rates for operation from 265'F and below were calculated using an RCS pressure of 450 psia. This 450 psia RCS pretsure envelops the maximum RCS pressure which could be reached during a postulated overpressurization event- for which the LTOP system (SDCS Relief Valve) is aligned. This ensures that with the SDCS Relief Valve aligned from 265*F and below, the proposed heatup and cooldoen limits will bound all pressure conditions.
9
__ ~ __ . . _ _ _ _ _ _ _ - _ _ _. _ __
RCS hestup rates with the reactor head bolts tersioned and the RCS cold leg temperature equal to the minimum boltup temperature of 86*F are limited to 14*F/hr. The intersection of the RCS pressuro 9f 450 psia with the 4PF/hr heatup curve provides the temperature (147.4*F) at which the heatup iate can be increased to 40*F/hr. The temperatures foi- which higher heatup rates are allowed are determined in a similar manner. This methodology determines the j minimum RCS temperature required for discrete heatup rate values. A l continuous curve of allowable RCS heatup rates versus RCS coolant temperatures 4 is provided in Figure 3.4-3. The minimum temperature at which the heatup rate !
of 60*F/hr is permitted is 180*F.
The core critical limit curve in Figure 3.4-2 is in accordance with 10 CFR 50 Appendix G, which requires the reactor vessel temperature to be 40*F above the heatup P-T limit when the core is critical. The Lowest Service Temperature (LST) in Figure 3.4-2 is calculated in accordance with ASME Section.111, Article NB-2332(b), which requires an LST of RT , + 100*F for piping, pumps,-
and valves. Our calculations, inc;uding instrument uncertainties, arrived at an LST of 208'F. Below this LST, 20 percent of the system hydrostatic test pressure cannot be exceeded. Inservice test allowable P-T limits assume hydrostatic pressure tests and RCS inservice leak tests are conducted at isothermal conditions. However, allowance for a 10*F/hr temperature deviation was accounted for in the analysis. Inservice testing is not conducted from the Remote Shutdown panel.
For the RCS P-T limits in Figure 3.4-4, the RCS pressure is decreased from 1200 psia at the LST of 202*F to 680 psia at the new LST of 208'F. The 100*F/hr cooldown curve intersects the 450 psia RCS pressure at 175*F. Below this temperature allowable cooldown rates, based upon an RCS pressure of 450 psia, are provided as a function of RCS temperature in Figure 3.4-5. These cooldown rates range from 7.8'F/hr at 86*F to 100*F/hr at 175'F.
Remote Shutdown cooldown operational limits are depicted in new figures.3.4-6 and 3.4-7. Figure 3.4-6 provides the P-T limits and Figure 3.4-7 provides the allowable cooldown rates for Remote Shutdown operation to be effective until 8
- EFPY, The new Figures 3.4-6 and 3.4-7 provide more conservative limits
! because they include TLus for pressure for the shutdown instru.nents on the Remote Shutdown panel that have been found by analysis to be higher than the TLus for pressure for the Control Room shutdown instruments. The temperature TLUs for both the Remote Shutdown instruments and the Control doom shutdown l instruments are identical.
- The results of the transient analysis, i.e., the mass addition transient and l the energy addition transient analyses in the Updated Final Safety Analysis Renort (UFSAR) Section 5.2.2.11.2', " Design and Analysis," have been reviewed and approved by the NRC. Because there has been no LTOP system hardware or relief pressure setpoint modifications, the previous analyses are valid until 8 EFPY, The UFSAR will be revised to reflect the 1) revised LTOP enable temperatures for heatup and cooldown operations from the Control Room, 2) LTOP l enable temperature for cooldown from the Remote Shutdown Panel, and 3) updated material properties evaluated in our response to GL 92-01, Revision 1.
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[ SAFETY ANALYSIS:
i The proposed change described above shall be deemed to-involve a significart
- 5azards consideration if there is a positive finding in any of the following
_ areas: ,
3 h 1. Will operation of the' facility in accordance with this proposed change
!. involve a significhnt-increase'in the probability or consequences of an j accident previously evaluated?
l Response:- No.
I To compensate forlimits any increase in the reactor vessel- RT* ' onships are caused-by neutron irradiation, on pressure-temperature.relati ;
i periodically changed in accordance with 10 CFR $0,' Appendix G. -This :
! allows the materials for the pressure retaining components of- the.
reactor coolant pressure boundary to stay within their stress limits-
[ during any condition of normal l operation, including anticipated.
[ operational occurrences and: system hydrostatic tests, over its service '
! lifetime.
! The updates to-Figures 3.4-2, 3.4-3,E3.4-4, and.3.4-5 incorporete the: <
i changes to the P-T limits analyzed using conservative fluence-vglues.
i The new P-T 1imit curves (Figures 3.4_-6;and 3.4-7) for Remote Shutdown
! cooldown operation incorporate.the nigher TLUs for-presc for shutdown s
, instruments on the-Remote < Shutdown panel ac compared ts pressure
- - TLUs for Control Room shutdown instruments.- The tempei e TLUs for
[ both the Remote Shutdown instruments and the Control Room shutdown
! instruments are identical. These updates maintain ~ margins o.f safety l against nonductile failure of the . reactor pressure vessel.besed on the
[ results of the Unit 3 surveiliance_ capsule analysis and the updated material properties evaluated in response: to GL- 92-01, Revision 1=,
Therefore, the proposed change will not_ involve a sign)ficant; increase in the probability or consequences of any accident-previously evaluated, o
l The change'to the LTOP enable temperatures is in accordance with NUREG-
[ 800 BTP_ RSB-52, Revision 1. The results of the most limiting energy;
- addition transient which is driven by the differential temperature ~ -
j between the RCS and the. steam generator,is not changed by this revision-
- to the LTOP.- ' As such-the proposed change Lis: bounded by.the original: -
F analysis. Therefore, the proposed LTOP enable temperature change will L not involve a significant increase _in the probability or consequences!of U
nny accident-previously evaluated.
I 2. Will operation of the facility in accordance with this proposed change-create the possibility of a new or_different kind of accident from any
- . accident.previously evaluated?-
l Response: No.
L -
- j. The proposed change incorporates the change in reactor vessel RTuor'from
-different irradiation stages to reflect _the . accumulation.of fast.. neutron I
exposure. Any increase-in RTuor due to irradiation is compensated for
- i. 11 L
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by limiting pressure-temperature relationships in accordance with 10 CFR 50 Appendix G to ensure pressure-retaining components of the reactor coolant pressure boundary stay within their stress limits over their service lives. Therefore, the pro)osed change will not create the possibility of a new or different (ind of accident from any previously evaluated.
The proposed LTOP enable temperature changes will not create the i possibility of a new or different kind of accident from any previously
. evaluated.- All LTOP desigr basis energy Mdition and mass addition transients have been previously evaluated aiid remain bounding. The proposed changes do not result.in any system configuration changes which would affect the capabil ty of the SDCS Relief Valve to respond to design basis transients. Operation of the plant in accordance with TSs 3.4.1.3, " Hot Shutdown," and 3.4.1.4.1, " Cold Shutdown-Loops Filled,"
remain uachanged.
- 3. Will opention of tr 'acility in accordance with this proposed change -
invalve a sigt4f h....t reduction in the margin of safety?
Response: i;o.
1, 4
The purpose of the P-T limit curves is to limit thermal stresses induced by the normal load tran> Ents, reactor trips, and unit startup and shutdown operations. The proposed revision to the P-T limit curves 4 incorporates the effects of neutron-induced embrittlement in the pressure-retaining component materials to preserve the margin of safety requireu by 10 CFR 50, Appendix G. Therefore, the proposed change will j net involve a significant. reduction in the margin of safety.
The proposed LTOP enable temperatures of 265aF .for heatup, 249af for normal and Remote Shutdown cooldown meet the recommendations of'NUREG-800 Branch Technical Position RSB 5-2, Revision 1. .The proposed LTOP enable temperatures will assure the SDCS Relief Valve will be aligned to the RCS-system to mitigate the con equences of low temperature overpressure events. Furthermore, the maximum RCS pressure used in the analysis bounds the' worst case scenario of _the postulated overpressurization event. Hence, it is assured that the P-T limits will not be' exceeded by overpressurizati v transients. Therefore, the proposed change'will not involve a significant reduction in~ the margin
- of safety.
f SAFETY AND SIGNIFICANT HA7ARDS CONSIDERATION DETERMINATION Based on the above Safety Analysis, it is concluded that: (1) the proposed change does not constitute a significant hazards consideration as defined by 10 CFR 50.92; -(2) there is a reasonable assurance that the health and safety of the public will riot be endangered by the proposed change; and (3) this action will not result in a condition which significantly alters the impact'of the station on the environment as described in the NRC Final Environmental Statenient .
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