ML20081K933
| ML20081K933 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 05/31/1991 |
| From: | ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY, ASEA BROWN BOVERI, INC. |
| To: | |
| Shared Package | |
| ML20081K928 | List: |
| References | |
| A-MPS-ER-004, A-MPS-ER-4, NUDOCS 9107020179 | |
| Download: ML20081K933 (25) | |
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- m.ns z, so. s u. es ON LOW TEMPERATURE OVERPRESSURE PROTECTION ANALYSIS FOR ARKANSAS NUCLEAR ONE UNIT 2 FOR 21 EFFECTIVE FULL POWER YEARS PREPARED FOR:
ENTERGY OPERATIONS, INC.
ARKANSAS NUCLEAR ONE UNIT ?
RUSSELLVILLE, ARKANSAS BY:
ABB COMBUSTION ENGINEERING NUCLEAR POWER COMBUSTION ENGINEERING, INC.
PLANT ENGINEERING SERVICES 1000 PROSPECT HILL ROAD WINDSOR, CT 05095-0500 MAY 1991 A-MPS-ER-004 CONIBHETRON ENGINEERING 9107020179 9w6W PDR ADOCK0500gG, P
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Entergy Operations, Inc. .
Arkansas Nuclear One - Unit-2 Low Temperature Overpressure Protection Analysis for 21 EFPY Report TABLE OF CONTENTS Section No. Title Roe N3.
1.0 INTRODUCTION
1-1.1 General 1 1.2- ANO-2 LTOP System 1-1.3 Objective 2 2.0 METHOD AND APPROACH 3 3.0 ANALYSIS ASSUMPTIONS 4
4.0 DESCRIPTION
OF ANALYSIS 9 4.1 Relief Valve Discharge -9 4.2 Peak Transient Pressure 9 4.3 Adequacy of Relief Valve Setpoint 10 4 '. 4 Oper, ting Limits 12 4.5 Analysis Results 14 5.0- CONCLUSION 19 6.0 IMPLEMENTATION OF RESULTS 20
7.0 REFERENCES
21 i.
l l:
L i
A-MPS-ER-004 Page ii
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LIST OF FIGURES Fioure No. Title Pse ib.
4-1 Operating Limits for Heatup up to 16 80*F/hr 4-2 Operating Limits for Heatup up to 17 100'F/hr 4-3 Operating Limits for Cooldown 18 A-MPS-ER-004 Page iii
Section 1.0
. INTRODUCTION 1.1 General The primary objective of low temperature overpressure protection (LTOP) systems is to preclude violation of applicable pressure-temperature (P-T)
~
limits during startup and shutdown conditions. These P-T limits are usually valid for a finite time period such as one cycle. 5 EFPY, etc. and are based upon the irradiation damage prediction at the end of the period.
Accordingly, each time new P-T limits are to become effective, the LTOP system needs to be re-analyzed and modified, if necessary, to continue its '
function.
1.2 ANO-2 LTOP System A typical LTOP system includes pressure relieving devices, alarms and a number of administrative and operational controls. At Arkansas Nuclear One - Unit 2 (ANO-2), LTOP is provided by two redundant valves connected to the top of the pressurizer. The valves (Tag Nas. 2PSV-4732 and 2PSV-4742) are safety relief valves, Model DB-32P/SP/54, orifice area 6.38 sq.
in., made by J. E. Lonergan Company. Each valve has the same opening setpoint of 430 psig and is capable of mitigating the design basis pressurization event which is a full safety injection initiation from water-solid conditions. '
Both valves have to be aligned to the RCS by the opening of the corresponding isolation (block) valves between 275'F and 270*F during cooldown, and isolated from the RCS between 275'F and 280'F, during heatup. An alarm circuit is provided to alert the operator if the RCS temperature drops to 270*F and any isolation valve is not fully open. (A description of the LTOP system is provided in Reference 1, Sections 5.2.2.4, 7.6.1.3 and 7.6.2.3.)
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. . _ . . . . . . - - . - . . _ _ =
The above provisions, in combination with Technical Specification heatup tnd cooldown limitations (Reference 2, LCO 3.4.9.1) comprise the ANO 2 LTOP system which provides assurance that the Technical Specification RCS P-T limitations for 0 to 10 years of full power operation (Reference 2, Figure 3.4-2) will not be violated it, the case of the design basis pressurization event.
The licensing and ' design bases for _ the existing ANO-2 LTOP system are provided in Reference 3 which modifies the original LTOP analysis contained in Reference 4.
1.3 Obiective ,
In the anticipation _ of the plant approaching the end of the operating-period for which the current P-T limits are applicable, Entergy Operations initiated this effort. The scope included a development of Appendix G and LTOP P-T limits, both based upon the irradiation damage prediction at 21 effective full power years (EFPY), and a new LTOP analysis.
- In an attempt to- maintain adequate operating flexibility, Entergy L Operations established certain targets .%r the LTOP analysis. As a L . result, the objective of the analysis was to demonstrate that the targeted l relief valve setpoint and heatup and cooldown limitations provide
! assurance that l
(1) the applicable LTOP P-T limits are not exceeded during the design basis pressurization event, and (2) the applicable Appendix G P-T limits yield a sufficient RCS operating window.
l L The following sections document the method, assumptions and results of the i LTOP analysis.
A-MPS-ER-004 Page 2 l
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Section 2.0 METHOD AND AFPROACH In order to meet the objective, stated in Section 1.3, the analysis was performed in two steps.
First, the peak transient pressure in the design basis pressurization event and the applicable LTOP P-T limits were graphically compared to verify whether the latter are located above the former. If this is the case, as it was in the subject analysis, the applicable P-T limits would not be exceeded during the design basis pressurization event. As a result, the targeted her'.up and cooldown limitations are met.
The peak transient pressure was determined based upon the targeted relief valve setpoint, a conservative valve discharge model, and mass input into the RCS during the design basis event. The applicable LTOP P-T limits were composite limits for each targeted rate that consisted of the most limiting portions calculated for either a corresponding ramp rate, or a step change at half the rate in a half hour.
Next, composite operating curves for heatup and cooldown that consisted of the Appendix G P-T limit curves for the targeted rates and the relief valve setpoint were generated and evaluated to demonstrate that a sufficient RCS operating window existed. Note that an RCS operating window is a pressure range between the applicable RCP operating curve and either the relief valve setpoint, or the applicable Appendix G P-T limits, whichever is more limiting.
A-MPS-ER-004 Page 3
x, i Section 3.0 ANALYSIS tSSUMPTIONS
.This section presents the major assumptions-that were utilized in the subject LTOP analysis. Also included are the relief valve- setpoint and heatup/cooldown limit targets established by Entergy Operations.
(a) Relief Valve Setooint The relief valve opening setpoint target is 450 psig, per Reference 5.
(b) Heatuo/Cooldown Limits The heatup rate target is 80'F/hr at all temperatures, per Reference 5.
The cooldown limit-targets are as follows:
Etta Temoerature Rance 100'F/hr T, > 230* F 60*F/hr. 150'F s T, s 230*F 25'F/hr T, < - 150
- F The above cooldown limit targets per Reference 6 supersede the original targets per Reference 5.
(c) Reference P-T Limits
" The LTOP P-T. limits for 21 EFPY that were developed in the course of this effort and provided in Reference 7 are used as the basis for the verification of the adequacy of the relief valve setpoint per Item (a) above.
A-MPS-ER-004 Page 4 l
Similarly, the Appendix G P-T limits for 21 EFPY that were also developed l in the course of this effort and provided in Reference 17 are used as the basis to verify that a sufficient operating window is available.
This approach was first proposed in Reference 8 in response to an Entergy Operations' request, was included in the list of analysis assumptions, Reference 9, and was consequently concurred with by E01 in Reference 5.
The P-T limit curves for cooldown that are used in the LTOP analysis are composite curves that consist of the most limiting pressure values calculated assuming either a ramp rate per Item (b) above or a step change at half the rate in a half an hour. (See Reference 6.)
(d) Means for LTOP The sole means for LTOP is the two existing relief valves, Tag Nos 2PSV-4732 and 2PSV-4742. Both valves are required to be aligned to the RCS for LTOP between the minimum boltup temperature and the LTOP enable temperature. Only one valve however is assumed to mitigate the design basis pressurization event, due to the single failure criteria per Reference 10.
This assumption is consistent with that used in Reference 4. The assumption was listed in Reference 9 and was consequently concurred with by E01 in Reference 5.
(e) Relief Valve Discharae Model It is assumed that during a pressurization event the relief valve remains closed until valve inlet pressure reaches 10% accumulation above tha opening setpoint, at which point the valve opens instantaneously, l
l A-MPS-ER-004 Page 5 l .
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This is.a conservative assumption since it results in valve opening delay which, in -turn, yields a greater opening pressure. 'Thus the lowest available valve inlet pressure value is. at 10% accumulation.
This assumption is a result of a comparison between the flow characteristics assumed in the original LTOP analysis, Reference 4 and the information provided in Reference 11, as was proposed in Reference 9.
(f) Relief Valve Back Pressure Relief valve back pressure used to calculate flow ratt is 100 prig,-per.
' Reference 12.
(g) Desian Basis Event The existing design basis pressurization event, mass addition due to a full safety injection initiation is assumed as the basis in establishing the peak transient pressure. The existing mass input _ from simultaneous operation of two HPSI and three' charging pumps (1600 gpm, per Reference 4)
L is however re evaluated due to a change in the relief valve setpoint.
This assumption is based on Item 14 in Reference 9 and reflects E0!'s comment provided in Reference 5.
(h) Inlet Pinino Pressure Droo L
'The existing relief valve inlet piping pressure drop, i.e. between the pressurizer and theLvalve inlet (30 psi, per Reference 4) is assumed .in the calculation of the peak transient pressure in the pressurizer since the as-built-inlet piping, per References 13 and 14 is essentially similar to that assumed in the original analysis, Reference 4, and provided in References 15 and 16.
i A-MPS-ER-004 Page 6
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(i) LTOP Enable Temoeratures An LTOP enable temperature identifies the upper temperature limit at which the LTOP system (relief valves) must be actuated (i.e. aligned to the RCS) during cooldown, or at which the LTOP system can be disabled during heatup. The subject LTOP enable temperatures, T, are as follows:
P-T Limit Basis T, per Reference 7 T, for Use in the Analysis Heatup at 100*F/hr 225.l'F 226*F Heatup at 80*F/hr 209.4*F 210*F Cooldown at 100'F/hr 206.5'F 207'F The above temperatures include temperature instrumentation loop uncertainty of 30'F.
l (j) Press'Jrizer Fluid Conditions l
At the.beginning of the design basis event the pressurizer is assumed to L be filled with saturated water at a pressure equal to 90% of the valve opening setpoint, which is recommended by the manufacturer as the maximum operating pressure with the relief valves aligned for LTOP (see Reference 11).
This assumption reduces water subcooling during valve discharge which, in turn, reduces discharge flow rate and thus increases the peak transient pressure, which is conservative for the purposes of this analysis.
(k) RCP Start with Steam Volume
-During an RCP start event with (a) secondary-to-primary temperature difference of s 100*F, (b) pressurizer steam volume of 2 800 cu ft, and A-MPS-ER-004 Page 7
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(c) initial pressurizer pressure at 5 300 psia, transient pressure does not exceed 365 psia-for at least 10 minutes from the initiation of the event.
This is; a result of an original analysis that was aimed at preventing lifting of the relief valves during RCP start events. (See Reference 4, Section 4.2.1.) Note that the original-relief valve setpoint was 350 psig (365 psia).
It is assumed that applicable Appendix G P-T. limits will not be exceeded during- an RCP start (provided that the above limitations on initial pressure, pressurizer level and secondary-to-primary temperature difference are met), as long as these Appendix G limits are greater than 365 psia.
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Section
4.0 DESCRIPTION
OF ANALYSIS 4.1 Relief Valve Discharoe Using the data and assumptions per Section 3.0, Items (a), (d), (e), (f) and (j), liquid discharge through the relief valve was detcrmined, using the guidance provided in the "Special Water Sizing" section of Reference 11 that applies to less than saturated high temperature liquids which flash to vapor at relief etnditions.
At the valve inlet pressure equal to 10% accumulation above the targeted setpoint of 450 psig (i.e. at Pini,, - 510 psia), the discharge flow rate was calculated to equal 1615 gpm. This flow rate is for water, initially at saturation at P - 420 psia (see Section 3.0, Item j). For comparison, for water at 70*F, the discharge flow rate is 1920 gpm.
Taking into account the relief valve inlet piping pressure drop (Section 3.0, item h), pressurizer pressure corresponding to Pini,, - 510 psia i s Pp ,,
540 psia. Thus, at Pp ,, - 540 psia, a single relief valve is capable of relieving 1615 gpm of water.
4.2 Peak Transient Pressure This section determines the mass input flow rate in the design basis event at Pp ,, - 540 osia and the peak transient pressure. Per Section 3.0, Item g, the design basis pressurization event is mass addition from 2 HPSI and 3 charging pumps. A charging pump's capacity is 44 gpm and is independent of RCS pressure (Reference 4, Appendix A, Table 1). As for HPSI pump capacity, it is a function of RCS pressure.
Assuming that a reference point for RCS pressure is at the cold leg elevation where the HPSI pumps' injection takes place, RCS pressure that corresponds to Pp ,, 540 psia is equal to 548.9 psia, where the A-MPS-ER-004 Page 9 i
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- ed 4 -- 4a'A -- he-m-4 4 4A h4 L-- a--- J -- 4---L- -+ J-ha m. A difference is attributed to the static head due to a difference -in the elevations between the pressurizer level and the cold leg centerline. The
- flow induced pressure drop between the reference injection point and the surge line is not taken into account in calculating the RCS pressure.
This is conservative, since it reduces the RCS pressure against which HPSI pumps deliver which, in turn, increases HPSI pump flow rates into the RCS, At P,c - 548.9 psia, 2 HPSI pumps' input flow rate into the RCS is 1372 gpm, as determined from Figure 2 of Reference 4. Therefore, a total 2 HPSI + 3 charging pump's input into the RCS is equal to 1504 gpm, at Pp ,,= 540 psia.
A comparison of the above flow rate with'a single valve discharge capacity (1615 gpm, Section a.1) indicates that at P,,, 540 psia valve capacity exceeds mass input during the design basis event. Consequently, an equilibrium between mass input and valve discharge would occur at a pressure, lower than 540 psia.
That lower, equilibrium pressure should be considered to be the peak transient pressure, if available. Consistentwithitem(e),Section3.0, however pP ,, - 540 psia is conservatively assumed to represent the peak transient pressure in the design basis event.
4.3 Adecuacy of Relief Valve Setooint The peak transient pressure determined in Section 4.2 was evaluated along with the applicable LTOP P-T limits (Section 3.0, Items (b), (c), and (i))
to verify the adequacy of the- targeted relief valve setpoint for LTOP.
The results of this evaluation are sumarized below:
(1) A heatup rate of up to 100*F/hr can be utilized at any RCS temperature, with a corresponding LTOP enable temperature of 226'F.
A-MPS-ER-004 Page 10
For the target heatup rate of up to 30'F/hr, the LTOP enable temperature is 210'F.
(2) A cooldown rate of up to 100'F/hr can be utilized above 230*F, as targeted in Section 3.0, item (b). This rate can also be utilized above 207'F which is the LTOP enable temperature during cooldown.
NOTE 1: The reference step change P-T limits are only available' at t,c, 2 230*F. If these limits are available at t,c, < 230'F, a lower than 230'F temperature limit for the 100*F/hr rate could be realized.
(3) A cooldown rate of up to 60*F/hr can be utilized above 150'F, as targeted in Section 3.0, Item (b).
NOTE 2: The reference step change P-T limits are only available at t,c 2 150*F. If these limits are available at ties < 150*F, a lower than 150*F temperature limit for the 60'F/hr rate could be realized.
(4) A cooldown rate of up to 25'F/hr can be utilized at any RCS temperature.
Thus, a single LTOP relief valve, with a setpoint of 450 psig when aligned to the RCS below the LTOP enable temperature provides assurance that the applicable LTOP P-T limits are not exceeded during the design basis event.
The heatup and cooldown limitations targeted by Entergy Operations are thus met with a significant margin.
A-MPS-ER 004 Page 11
4.4 Operatino limits Operating limit curves were developed to evaluate the RCS operating window and also to provide operating guidelines during heatup and cooldown conditions.
Each curve is a composite curve that consists of appropriate Appendix G P-T limits and the relief valve setpoint of 465 psia. It extends from the minimum boltup temperature of 70*F to a temperature corresponding to the intersection between this curve and the safety valve setpoint of 2500 psia.
The curves identify operating pressure l'imits for normal evolutions during heatup, cooldown, or isothermal conditions, including RCP starts with a steam volume in the pressurizer. Exceeding these limits during normal evolutions will result in violation of Technical Specification P-T limits (i.e., Appendix G limits), or in relief valve actuation. It must be noted that having the relief valves assigned the function of protecting the LTOP P-T limits implies that the Appendix G P-T limits which are more restrictive may be exceeded, but only in the case of an inadvertent pressurization event in the RCS.
The operating limit curves were developed for heatup up to 80'F/hr, heatup up to 100*F/hr and cooldown, as detailed below.
The coeratina limit curve for heatuo uo to 80*F/hr (the taraet limit) extends up to 328'F (see Figure 4-1). The curve mostly consists of the 80'F/hr Appendix G heatup limits, except between 175'F and 210'F where the reitef valve setpoint of 465 psia (450 psig) is more limiting.
l The curve's most limiting (the lowest) pressure is 394 psia (at 130'F),
l i.e. greater than the 365 psia peak transient pressure per Section 3.0, Item (k). Accordingly, the first idle RCD can be started at any temperature, provided the limitations in Item (k) are met.
A-MPS-ER-004 Page 12 1
The operatina limit curve for heatuo un to 100'F/hr extends up to 342*F (see Figure 4-2).
NOTE: This curve is provided as an option. A heatup rate up to 100*F/hr can be utilized at all RCS temperatures and may be used by E01, if desired, instead of the target rate of 80'F/hr.
The curve mostly consists of the 100*F/hr Appendix G heatup limits, except between 196*F and 225'F where the relief valve setpoint of 465 psia (450 psig) is more limiting.
The curve's most limiting (the lowest) pressure is 369 psia (at 140*F),
i.e. greater than the 365 psia peak transient pressure per Section 3.0, item (k). Accordingly, the first idle RCP can be started at any temperature, provided the limitations of Item (k) are met.
The operatino limit curve for cooldown extends up to 291'F. (See Figure 4-3). The curve consists of the following limits:
(1) Appendix G P-T limit for 25'F/hr cooldown between 70*F and 125'F, (2) Relief valve setpoint of 465 psia between 125'F and 207'F, (3) Appendix G P-T limit for 60'F/hr. cooldown between 207'F and 230*F, and (4) Appendix G P-T limit for 100'F/hr cooldown between 230*F and 291*F.
As was indicated earlier (see Item (2), Section 4.3), a cooldown rate of up to 100*F/hr can be utilized above 207'F. Furthermore, the most limiting Appendix G P-T limits for cooldown at 60*F/hr and 100*F/hr are nearly identical between 207'F and 230*F. Accordingly, utilizing a cooldown rate of up to 100*F/hr down to 207'F (instead of 230*F) will not result in a more restrictive operating limit curve.
A-MPS-ER-004 Page 13
The curve's most limiting (the lowest) pressure is 349 psia (at 70'F),
i.e. below than the 365 psia peak transient pressure per Section 3.0, Item (k). Accordingly, the first idle RCP can be started at temperatures above 85'F (at which the curve's lowest limit equals 365 psia), provided the limitations of Item (k) are met.
Evaluation of the operating limit curves for heatup and cooldown indicates that with-the new Appendix G curves for. selected heatup and cooldown rates and the new, raised relief valve setpoint, the new operating pressure limits yield an adequate RCS ope *ating window for the operating period ending at 21 EFPY.
4.5 Analysis Results The results of the analysis documented in this report are as follows:
- 1. The applicable LTOP. P-T limits will not be exceeded in the case of the design basis pressurization event if:
(a) both relief valves, Tag Nos 2PSV-4732 and 2PSV-4742 are aligned to the RCS between the minimum boltup and LTOP enable temperatures; (b) each valve's opening setpoint is s 450 psig; (c) LTOP enable temperatures are 2 210*F for heatup at 5 80*F/hr (2 226*F, at s 100'F/hr) and 2 207'F, for cooldown; and finally A-MPS-ER-004 Page 14
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-(d) RCS heatup and cooldown rates are maintained as follows:
Heatuo: s 100'F/hr, at all RCS temperatures Cooldown:
s 100'F/hr , at t,c, > 207'F s 60*F/hr , at t,e, > 150*F s 25'F/hr , 'at t,c, > 70'F
- 2. Operating limit curves, Figure 4-1 (or 4-2) and 4-3 provide the operating pressure limits that should be adhered to during startup and shutdown evolutions. Failure to maintain RCS fluid conditions below and to the right of these curves will result in violation of Technical Specification P-T limits (i.e., Appendix G limits), or in relief valve actuation.
Figure 4-1 provides the operating lim n curve for heatup at-s 80*F/hr, while. Figure 4-3 provides the operating limit curve for cooldown. If heatup at s 100'F/hr is selected for implementation, Figure 4-2 should be used.
- 3. - RCP starts with a steam volume in the pressurizer _are allowed at any temperature,-except' at s 85'F during cooldown, provided pressurizer steam : volume is 2 800 cu . _ft, . initial : pressurizer pressure 'is s 300 psia and secondary-to-primary temperature difference is s 100*F.
A-MPS-ER-004 Page 15
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. o:r Section.
5.0 CONCLUSION
The results of the analysis presented in Section 4.5 indicate that the objective stated in Section 1.3 is met. More specifically it has been demonstrated that the = relief valve setpoint and heatup/cooldown limitations targeted by Entergy Operations, when implemented along with valve alignment requirements, will provide assurance that th'e applicable LTOP P-T limits are not exceeded during the design basis pressurization event.
Furthermore, while adequate LTOP is provided, plant operational flexibility is-not significantly impaired, ,
Section 6.0 contains the recommendations for the implementation of the results-of this- analysis.
f s
A-MPS-ER-004 Page 19
.* .e
, ;; .Section 6.0 IMPLEMENTATION OF 4,.SULTS The following describes the recomended steps that may need to be taken in order to implement the LTOP analysis results:
- 1. Modification of the valve to raise the valve opening setpoint.
- 2. Verification of valve adequacy for higher pressure service.
- 3. Revision of Technical Specification LCO 3/4.4.9 to include revised heatup and cooldown rates and a new Figure 3.4-2. Revision of the corresponding Bases.
- 4. Development of a new technical specification dedicated to LTOP.
- 5. Revision of SAR, Sections 5.2.2.4, 5.5.13.2, 7.6.1.3 and 7.6.2.3 to include the new relief valve setpoint and LTOP enable temperatures. Note
- that no wording change is required.
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- 6. Revision of the following operating procedures:
l l
- 2103.02, Filling and Venting the RCS
- 2102.002, Plant- Startup
- 2102.10, Plant Shutdown and Cooldown NOTE: Other procedures may also need to be revised as appropriate.
1.
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Section
7.0 REFERENCES
- 1. Arkansas Nuclear One - Unit 2, Safety Analysis Report, Amendment No. 8,
- 2. Arkansas Nuclear One - Unit 2, Technical Specifications, Original Issue.
- 3. Letter A-CE-6549, '" Revised Cooldown Curves," F. C. Sernatinger (CE) to D. R. Sikes (AP&L), 7 September 1977.
- 4. Letter A CE-6352,
- Low Temperature Overpressure Protection for Arkansas Nuclear One - Unit 2," F. C. Sernatinger (CE) to D. R. Sikes (AP&L),
16 June 1977.
- 5. Letter ANO-91-2-00192, " Development of ANO-2's Pressure Temperature and LTOP Limitations," K. M. Head (E01) to C. D. Stewart (ABB CE),
1 March 1991.
- 6. Conversation Memorandum, " Appendix G P-T/LTOP P-T Limits," K. Head (E01) to N. Zavacky and P. Hijeck (both ABB CE), 2 April 1991.
- 7. Final Report on Low Temperature Overpressure Protection Pressure-Temperature Limits for Arkansas Nuclear One Unit 2 for 21 Effective Full Power Years, ABB CE Report No. A-MPS-ER-003, May 1991.
- 8. Letter A-MP. 0001, " Proposal for AN02 Low Temperature Overpressure Protection P-T Limits and LTOP Evaluation," C. D. Stewart (ABB CE) to C. H. Turk (E01), 15 January 1991.
- 9. Letter A-MPS-91-006, " Analysis Assumptions for ANO Unit 2 Pressure
! Temperature Limit Development and Low Temperature Overpressure Protection Evaluation", C. D. Stewart (ABB CE) to K. Head (E01),12 February 1991.
A-MPS-ER-004 Page 21 l
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- 10. Branch Technical Position RSB 5-2, "Overpressurization Protection of Pressurized Water Reactors While Operating at Low Temperatures," Rev.1, November 1988.
- 11. Lonergan Safety Relief Valves, Manufacturer's Handbook,1986.
- 12. Lonergan Drawing No. A2895, " Composite Drawing DB-30/SP-S4, Safety Relief Valve for Nuclear 5ervice, Rev. D.
- 13. Bechtel Drawing 2GCB-514-1, "Large Pipe Isometric, Reactor Coolant System", Rev. 4.
- 14. Bechtel Drawing 2BCA-14-1, "Large Pipe Isometric - Reactor Building, Reactor Coolant System", Rev. 13.
- 15. Letter BCL 2-1144, " Reactor Coolant Overpressurization Relief System,"
E. H. Smith (Bechtel) to F. C. Sernatinger (CE), 31 May 1977.
- 16. Letter BCT 2-00, "R.V. Low Temperature Overpressuri:ntion (LTOP),"
E. H. Smith (Bechtel) to F. C. Sernatinger (CE), 25 May IS/7. (Telex).
- 17. Final Report on Reactor Vessel Appendix G Pressure-Temperature Limits for Arkansas Nuclear One Unit 2 for 21 Effective Full Po,ter Years, ABB CE Report No. A-MPS-ER-002, May 1991.
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