ML18093A343
| ML18093A343 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 09/02/1987 |
| From: | Public Service Enterprise Group |
| To: | |
| Shared Package | |
| ML18093A342 | List: |
| References | |
| NUDOCS 8709090222 | |
| Download: ML18093A343 (16) | |
Text
REVISED PAGES TECHNICAL SPECIFICATIONS
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TABLE 2.2-1 REACTOR TR!P SYSTEM INSTRUMENTATION TRIP SETPOINTS FUNCTIONAL UNIT
- 2. Power R*ange, Neutron Flux
- 3. Power Range, 'Neutron Flux, High Positive Rate
- 4. Power Range, Neutron Flux, High Negative Rate *
- 5. Intermediate Range, Neutron Flux
- 6. Source Range, Neutron Flux
- 7. *overtemperature AT
- 8. *overpower AT
- 9. Pressurizer Pressure--Low
- 10. Pressurizer Pressure--High
- 11. Pressurizer Water Level--High TRIP SETPOINT Not Applicable Low Setpoint - < 25% of.RATED THERMAL POWER -
High Setpoint - < 109% of RATED THERMAL POWER
< 5% of RATED THERMAL POWER with
- . a time constant > 2 second
< 5% of RATED THERMAL POWER with a time constant > 2 Second
< 25% of RATED THERMAL POWER
~ 105 counts per second See Note 1 See *Note 2
~ 1865 psig
~ 2385 psig
~ 92% of instrument span
?
- 12.,loss of Flow
~ 90% of design flow per loop*
- Design flow is 87,300 gpm per loop.
ALLOWABLE VALUES Not Applicable Low Setpoint - < 26% of RATED THERMAL POWER -
High Setpoint - < 110% of RATED THERMAL POWER
< 5.5.% of RATED THERMAL POWER with a time constant ~ 2 second
< 5.5% of RATED THERMAL POWER with a time constant ~ 2 second
< 3()%.of RATED THERMAL POWER
~ 1.3 x 105 counts per second
- See Note 3 See Note,4
?_ 1855 psig
~ 2395 psig
~ 93% of instrument span
~ 89% of design flow per loop~
- ~ '
I
<=
- z
-I N
I \\0 Note 2:
TABLE 2.2-1 (Continued)
REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS NOTATION (Continued)
Overpower AT ~ AT0[K4-K5 ( t3S l T - K (T-T")-f (AI)]
l+t s 6
- 2 3
where:
ATO =
T
=
T"
=
K4 =
Ks =
KG =
t 3S l+t3S -
t 3 =
s =
f 2(AI) =
Indicated AT at RATED THERMAL POWER Average temperature, °F Referenc~ Tavg.at RATED THERMAL POWER< 577.9°F
- l. 080
- 0. 02/°F for.increasing average temperature and 0 for decreasing average temperature
- 0. 00119/°F for T > T"; K = 0 for T < T" 6
The function generated by the rate lag controller for Tavg dynamic compensation Time constant utilized in the rate lag controller for Tavg t 3 = 10 secs.
Laplace transform operator, Sec-1.
0 for all Al Note 3:
The channel's maximum trip point shall not exceed its computed trip point by more than
- :3 ~.l pe~.cent:.
Note 4:
'l'he channel's maximum t:rip point: shall not: exceed it:s computed t:rip point: by more t:han 3.0 percent:.
~.
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I U1 TABLE 2.2-1 REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS FUNCTIONAL UNIT
- 2. Power Range, Neutron Flux
- 3. Power Range, Neutron Flux, High Positive Rate 4.*Power Range, Neutron Flux, High Negatiye Rate
- 5. Intermediate Range, Neutron Flux
- 6. Source Range, Neutron Flux
- 7. Overtemperature AT
- 8. *overpower *AT
- 9. Pressurizer Pressure--Low
- 10. Pressurizer Pressure--High TRIP SETPOINT Not Applicable Low Setpoint - < 25% of RATED THERMAL POWER.-
High Setpoint - < 109% of RATED THERMAL POWER
< 5% of RATED THERMAL POWER with a time constant > 2 second
< 5% of RATED THERMAL POWER with a time constant ~ ~ Second
~ 25% of RATED THERMAL POWER
~ 105 counts per second See Nate 1 See Note 2
~ 1865 psig
_:: 2385 psig
- 11. Pressurizer Water Leve 1--Hi gh
< 92% of instrument span
- 12. loss of Flow
~ 90% of design flow per loop*
- Design flow is 87,300 gpm.per loop.
ALLOWABLE VALUES Not Applicable Low Setpoint - < 26% of RATED THERMAL POWER -
High Setpoint -
~ 110% of RATED THERMAL POWER
< 5.5% of RATED THERMAL POWER with a time constant ~ 2 second
< 5.5% of RATED THERMAL-POWER with a time const_ant ~ 2 second
< 30% of RATED THERMAL POWER 5
~ 1.3 x 10 counts per second See Note 3
- See Note *. 4*
> 1855 psig
< 2395-psig
_:: 93% of instrument span
~ 89% of design flow per loop*
- 1.
(/)
)>
r-l"Tl 3:
c z.....
-f N
N I \\0 Note 2:
TABLE 2.2-1 (Continued)
REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS NOTATION (Continued)
Overpower AT ~ ATO[K4-K5 *r t3S J T - K (T-T")-f, (AI)]
l+t s 6
2 3
where:
ATO =
T =
T" =
K4 =
Ks =
KG. =
t 3S
- l+t3S -
t3 =
s
=
f 2CAI) =
Indicated AT at RATED THERMAL POWER Average temperature, °F Reference Tavg at RATED THERMAL POWER< 577.9°F
- l. 080 0.02/°F for increasing average temperature and 0 for decreasing average temperature 0.00119/°F for T > T"; K = 0 'for T < T".
6.
The function generated by the rate lag controller for Tavg dynamic compensation Time constant utilized in the rate lag controller for Tavg
- t = 10 secs.
3 Laplace transform operator, Sec*1.
0 for all AI Note 3:
The.channel's maximum trip point shall not exceed its computed trip point by more than
- 3.;,1.pe:r:cer.i:t.,
--*~of:e '4':.* Tb,e 'cb.~n~el Is maximllm. ti'ip poin~,shaii :I_lOt -exceed its ~omputed trip*, point:, by -more than.
- 3.. o JS~rcent. - - * - -
- ~
~,,
REVISED PAGES LICENSING REPORT S-87-05
3.3 Electronic Modifications:
Each of the three T-hot RTDs per loop will be wired up to a low voltage amplifier (MV/I) and the three signals then averaged to produce one T-hot signal which will replace the loop's T-hot signal of the existing system.
The added electronics will be identical to the existing 7100 electronic hardware now used.
Figure 5.1 shows the concept and outlines the added modules required.
3.4 System Accuracy:
By retention of the mixing concept at the hot leg scoops, the sampling performed by the existing system, and therefore the process measurement accuracys will be preserved.
Secondly, the impact of the electronic modifications is considered minor.
The same rack functional checks and calibration accuracy requirements will be maintained.
Thirdly, the proposed WEED RTD has an overall sensor accuracy which is an improvement over the existing RTD's.
3.5 ALARA Benefits:
A 3000 man-rem dose savings is projected over the remaining life of the two plants as a* result of this modification assuming a 40-year Operating License.
The estimated dose of approximately 150 man-rem associated with the demolition and installation work of the RTD proposed modifications is accounted for in the overall dose savings.
This ALARA and cost benefit analysis takes into account the reduced radiation levels, reduced outage time, increased accessibility in the loop compartments, installation/demolition doses, maintenance requirements and the plant's reliability over the life of the plant. Rev. 1
4.3 Crossover Leg:
The return for the bypass loops is a 3" nozzle in the crossover leg.
This connection will no longer be used.
A 3" schedule 160 buttweld cap will be installed on this connection to close it off. (Figure 4-3) 4.4 RVLIS Connection:
Currently the Reactor Vessel Level Instrumentation System (RVLIS) taps off the bypass loop in two of the four hot legs.
Since the bypass loops will be eliminated, the RVLIS connection must be moved to the hot leg pipe.
A new penetration will be made in the hot leg at the same elevation as the previous connection to the bypass loop.
The hole size of the new penetration will be the same as exists at the current connection.
This will provide the same flow restriction in the new system as exists in the current system.
(Figure 4-4) 4.5 Inspection Welding and Hydrostatic Test Requirements:
4.5.1 Hot Leg & Cold Leg Thermowells and RVLIS Penetration.
The following requirements are applicable to the 12 hot leg RTD Scoops, 4 cold leg connections and 2 new RVLIS penetrations.
- 1.
Liquid penetrant inspect all accessible field machined surfaces in accordance with the 1974 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
- 2.
Welding to be in accordance with the 1974 edition with I summer 1975 addenda of Section XI of the ASME B&PV Code.
(Root Pass-GTAW, Fill-GTAW, or SMAW).
- 3.
Liquid penetrant inspect weld pass in accordance with the 1974 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
- 4.
Liquid penetrant inspect final weld pass in accordance with the 1974 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
- 5.
Weld material to be supplied in accordance with ASME Section II with additional requirement of ASME Section III NB-2400 (1983 edition). Rev. 1
4.5.2 Crossover Piping The following inspection and welding requirements are applicable to capping of the 3" Crossover piping at four locations.
- 1.
Liquid penetrant inspection all field macined surfaces in accordance with the 1974 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
- 2.
Welding to be in accordance with the 1974 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
- 3.
Liquid penetrant inspect final weld pass in accordance with the 1974 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
- 4.
Liquid penetrant inspect final weld pass in accordance with the 1~74 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
- 5.
Radiographically inspect the completed weld in accordance with the 1974 edition with summer 1975 addenda of Section XI of the ASME B&PV Code.
In addition, UT baseline will be performed.
- 6.
An open butt weld configuration will be used with helium as purge gas with approved water soluble dams for purge gas sealing.
- 7.
Weld material to be supplied in accordance with ASME Section II & additional requirement of ASME Section III NB-2400
( 19 8 3 edition)
- 4.5.3 Hydrostatic Test Requirements Hydrostatic testing of all nozzles will be done during inservice in accordance with 1974 edition with summer 1975 addenda of the ASME Section XI IWB 5000. Rev. 1
4.6 Analysis of RCS Penetrations:
The thermowells are pressure boundary parts which completely enclose the RTD.
They will be machined from a solid bar of SB-166, a nickel-chromium-iron alloy and will be shop hydrotested to 1.25 times the RCS design pressure.
The external design pressure and design temperature will be the reactor coolant system design pressure and temperature.
The RTD therefore will not be part of the pressure boundary.
For both the hot leg and cold leg, the nozzle, thermowell, and the entire thermowell/nozzle assembly will each be analyzed to the ASME B&PB Code,Section III, Class 1.
The analysis of the entire assembly will consider the weight of the RTD, the RTD head assembly and an assumed length of the cabling.
The effect of the seismic and flow induced loads will also be considered.
Seismic response spectra specific to Salem will be used.
Flow induced vibration will also be evaluated.
The crossover leg connection will be analyzed to the same requirements as the hot and cold leg connections.
Since the connection will be capped and have no piping loads, stress levels will be lower than what exists in the current system.
The change in the RVLIS piping and the new connection to the hot leg will be analyzed in accordance with ASME Section III Class 1. Rev. 1
Based on an RTD head temperature of 160°F, the RTD will have a qualified life of 13 years.
The temperature at the RTD head has been conservatively determined to be less than 160°F.
The limiting component is the head potting compound.
If a lower head temperature is demonstrated, the qualified life can be increased.
The RTD has a 40 year qualified life with head temperature of 120°F.
The 4-wire dual RTD will be qualified by similarity to the tested 3-wire RTD.
The design and the technique of construction will be similar.
Dual element RTDs have been supplied and are in use at other operating plants including Waterford Steam Electric Station Unit-3.
The RTDs are provided with Resistance vs. Temperature (R vs T) calibration curves which are accurate to a specification of + 0.05°F at 554°F.
The RTD drift is specified to be within +1°F over a five (5) year period.
The accuracy of the WEED RTD considering calibration accuracy, repeatability, and drift is tabulated in Table 5-1.
The Weed RTD has the fastest response time of any available thermowell mounted RTD.
It is the best available qualified RTD for this application in terms of accuracy and drift.
The RTD calibration is performed by immersion in ice and oil baths whose temperature is monitored by a standard RTD calibrated to NBS standards.
The RTD/thermowell response time is measured by plunge method by causing a step change from ambient room temperature to elevated temperature.
All RTDs must meet a specified response time requirement and will, therefore, be interchangeable.
The dual element design provides an installed spare wired up to the Hagan instrument racks for use when the primary element failure is detected.
For this reason both elements of each RTD will be tested by Loop Current Step Response (LCSR) for in-situ response time after installation. Rev. 1 I.
.f N
N O"'.
I TABLE 5 -
1 WEED RTD ACCURACY*
ACCURACY (INCLUDES HYSTERESIS AND REPEATABILITY)
DRIFT (@ 22.5 MONTHS)
TOTAL UNCERTAINTY
- More conservative numbers were used for PSE&G setpoint analyses.
+0.3 F
+0.4 F
+0.7 F
7.0 SYSTEM FUNCTIONAL IMPACT The narrow range RTD temperature outputs are used for a number of purposes including reactor trips, Engineered Safety Features (ESF) actuation, and control functions.
These are discussed in Section 8.0.
7.1 System Accuracy:
The accuracy of the proposed system is an improvement over the existing system because of the following~
Hot leg scoop mixing has been retained as discussed in Section 4.1.
The replacement RTD has a improved accuracy over the existing RDF RTD's.
The accuracy of the new RTD's is discussed in Section 5.3.
Since the new RTD's will not be in contact with primary fluid and will be provided with a quick disconnect at the head, they can readily be removed.
Little, if any, decontamination would be required to allow transport to a testing facility to recalibrate the RTD's *
- Each hot leg RTD will be wired to a MV/I before averaging the three signals to obtain the loop's T-hot.
By having three parallel path T-hot RTD's, the error associated with the T-hot RTD's is reduced to 1/(3' compared to a single RTD.
The impact of the T-hot electronics (Figure 5-1) has been evaluated as very minor.
The existing overall channel functional checks and calibration accuracy requirements will be maintained.
The impact of rack drift has been considered in the evaluation.
There is no change to the cold leg's electronics; and therefore, no impact to the accuracy other than the increase obtained from a more accurate RTD. Rev. 1
The net result of the proposed modification is a slight improvement in the accuracy of the temperature related functions over the accuracy now achievable with the existing RDF RTD's in the bypass system.
PSE&G reviewed the impact of the proposed rnodif ications against the Salem setpoint study to verify that the accuracy requirements of the temperature related functions are met.
Salem presently assumes a 3-1/2% error in primary flow determination.
For Unit 2 this is controlled through Technical Specification 3.2.3.
For Unit 1, it is controlled through PSE&G procedures.
This allowance continues to be conservative.
PSE&G intends, as a separate effort, to demonstrate that a significantly reduced allowance error is acceptable.
7.2 Response Time Impact:
This rnodif ication will impact the following Technical Specification (T.S.) instrumentation response times:
Table 3.3-2 item #7 - Overternperature 6. T: add 1. 75 seconds.
Table 3.3-5 item #5 -
Stearn flow high with low-low T-AVG:
add 1.75 sec.
However, as discussed below although these T.S. 's times are affected, there is no change to any design bases since the total system response time remains unchanged.
The above Technical Specification response times do not include a 2.0 second delay, which is analytically established, to account for the existing RTD bypass loop thermal lag and travel time.
With the proposed system, this component is reduced by 1.75 seconds to 0.25 seconds.
The 0.25 seconds accounts for the transient time and thermal lag of the hot leg mixing scoop. (
Rev. 1
/
With the proposed system, the response time for the RTD's will be determined with the,,RTD's in the thermowells (using loop current step response methodology); therefore,-the thermal lag associated with the thermowell will be included in the RTD/thermowell is 1.75 seconds slower than the existing direct immersion RTD's response time.
Tabulating the overtemperature delta-T response time components.
Direct Immersion RTD Combined RTD/Thermowell Electronics/Electrical Subtotal (T.S. Response Time)
Loop or Scoop transient and thermal lag Total System Response Time Existing 3.0 sec.
N/A
- 1. 0 sec.
, 4.0 sec.
2.0 sec.
6.0 sec.
Proposed N/A 4.75 sec.
1.0 sec.
5.75 sec.
0.25 sec.
6.0 sec.
The affected ESF time responses are similarly tabulated in Tables 7-1 and 7-2.
In all cases, the total response time remains unchanged.
These times bound best estimate response times.
The allocated time for RTD/thermowell includes a 10% error allowance for LCSR testing.
Since the total system response time remains unchanged, no other evaluations/analyses are required to demonstrate the acceptability of changing the aforementioned T.S. times.
The time allocated for RTD/thermowell is conservative.
The specification prepared for the Salem plants requires that both elements be less than 4.0 seconds.
Typical test results for the same model Weed RTD in CE thermowells have demonstrated that times less than 4.0 seconds are realistic.
Similarly, the time allocated for electronics/electrical delay is conservative.
PSE&G has reviewed the time response tests performed during the last refueling for each unit for the electronics involved.
The ac~ual electronic/electrical delay is approximately'1/2 second~
'.. Rev. l
.. *~ ~
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