ML20129E949

Rev 0 to Low Temp Overpressurization Protection (LTOP) Setpoint Calculation

ML20129E949
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	05/14/1996
From:	Evans D COMMONWEALTH EDISON CO.
To:
Shared Package
ML20129E920	List: ML20129E915 ML20129E949 ML20129E975 ML20129E983
References
22S-B-004E-189, 22S-B-004E-189-R00, 22S-B-4E-189, 22S-B-4E-189-R, NUDOCS 9610280213
Download: ML20129E949 (35)

Text

NEP 12h2ZI Rsvision 0 CALCULATION COVER SHEET l

Zion Calculation No.: 22S-8-004E-189

Title:

Low Temperature Overpressurization Protection (LTOP) Setooint Calculation ZION NUCLEAR STATION Project

Title:

I&C Setooint Proaram PURPOSE: The purpose of this calculation is to determine a minimum Reactor Coolant System (RCS) cressure to be used in the development of new Appendix G Heatup & Cooldown Curves.

CALCULATION TYPE: _ lS SR SOFTWARE USED: None PLANT DESIGN CHANGE NUMBEP.: N/A PROJECT NUMBER: 4950 RELATED/ REFERENCED CALCULATIONS:

22S-8-004E-166. Rev. 0 COMPONENT IDENTIFICATION DRAWING NUMBERS:

f(2)1PT-403 NUMBERS: M49. Rev. E (2)1PT-405

___(2)1 PXX-403

_ (211PXX-405 0

REMARKS:

CHRON # N/A REV.

REVISION APPROVED DATE NO.

O Originalissue Q,4 yg 9610280213 961022 PDR ADOCK 05000295 P

PDR

4 Exhibit C NEP-12-02 Revision 2 page 1 of 2 COMMONWEALTH EDISON COMPANY CALCULATION TITLE PAGE 1

CALCULATION NO. 22d 004E-189 PAGE NO.: 1 OF 8

@ SAFETY RELATED 0 REGL'LATORY RELATED 0 NON-SAFETY RELATED CALCULATION TITLE:

Low Temperature Over-Pressurization Protection (LTOP) Setpoint Calculation i

STATION / UNIT:

ZION /1&2 SYSTEM ABBREVIATION: RC EQUlPMENT NO.

PROJECT NO.

4950 1PT-403 1PXX-403 1PT-405 1PXX-405 2PT-403 2PXX-403 2PT-405 2PXX-405 REV: O STATUS: Approved QA SERIAL,NO. QQCHRON NO. N/A DATE:

N/A PREPARED BY: Chuck Hallett NM1 DATE:

5/9/96 REVISION

SUMMARY

Rev. 0 - INITIAL ISSUE ELECTRONIC CALCULATION DATA FILES REVISED: None (Name ext / size /date/ hour min / verification method / remarks)

DO ANY ASSUMPTIONS IN THIS CALCULA*/lON REQUIRE LATER VERIFICATION YES ONO @

REV'EWED BY: Steve McCarthy O N

DATE: 5 //3/94 REVIEW METHOD: peln.'lal 8%lw COMMENTS (C OR NC):

Ak--

APPROVED BY: Dan EwanQg DATE: 5l ti [t, Issued: 3/25/96 9

Exhibit D NEP-12-02 Revision 2 COMMONWEALTH EDISON COMPANY CALCULATION TABLE OF CONTENTS PROJECT 4950 CALCUI.ATION NO. 22S-B-004E-189 REV. NO. O PAGE NO. 2 DESCRIPTION PAGE NO.

SUB-PAGE NO.

TITLE PAGE 1

TABLE OF CONTENTS 2

1. PURPOSE / OBJECTIVE 3

2. METHODOLOGY / ACCEPTANCE CRITERIA 3

3. ASSUMPTIONS AND LIMITATIONS 4

4. DESIGN INPUT 4

5. REFERENCES 6

6. CALCULATIONS 8

7.

SUMMARY

AND CONCLUSIONS 8

_m w w...... w.... -... e v n v v m, m e

+

CALCULATION NO. 22S-B-004E-189 PROJECT NO.

4950 PAGE NO. 3 l

1 PURPOSE / OBJECTIVE The p'trpose of this calculation is to determine a minimum Reactor Coolant System (RCS) pressure to be used in the development of new Appendix G Heatup & Cooldown Curves.

The minimum pressure will be based upon the existing Low Temperature Overpressurization Protection (LTOP) Power Operated Relief Valve (PORV) setpoints, the minimum head bolt up temperature of 65'F, and simultaneous operation of one Residual Heat Removal (RHR) Pump _

and one Reactor Coolant Pump (RCP). The minimum pressure will also account for instrumentation uncertainty, transmitter elevation static head and the American Society of Mechanical Engineers (A.S.M.E) Code Case N-514 maximum vessel pressure.

2.

METHODOLOGY / ACCEPTANCE CRITERIA 2.1 Methodology The RCS Heatup & Cooldown Curves are determined by analysis of reactor vessel weld properties, radiation exposure, etc. These curves represent operational limits for RCS pressure and temperature at low temperature operation, i.e. during heatup and cooldown.

The PORV setpoint ensures the operationallimit is never exceeded.

i A.S.M.E. Code Case N-514 [5.1.3] " Low Temperature Overpressure Protection Section XI, Division 1" states "LTOP systems shall limit the maximum pressure in the vessel to 110% of the pressure determined to satisfy Appendix G, para. G-2215 of Section XI, Division 1" Therefore the PORV setpoint value may be based on 110% of the Appendix G curve operationallimit. The Code Case N-514 maximum pressure is designated Pm..

i The Appendix G pressure limit refers to the pressure at the vessel beltline region, which region encompasses the center of the reactor core. The core centerline is the reference for all static and dynamic pressure corrections in this calculation.

The operational limit (Pw a m,n,.) is reduced by the following factors:

AP due to PORV overshoot (aPeonv).

AP between the transmitters and core center 1ine to account for dynamic head loss due to s

running the maximum permitted combination of RCPs and RHR pumps at 65'F (APm ).

static head effect due to differences between the core centertine and transmitter elevations (AP

).

instrument uncertainty (P-une%).

The Total Loop Errors calculated in Reference 5.2.1 are incorporated herein. Methodologies and references which pertain to incorporating the Total Loop Error are not repeated in this calculation.

2.2 Acceptance Criteria Not applicable REVISION NO.

r)

--- - - - - - - - -" - ~~~~'

i LummuNvveALlH hul3ON COMPANY

.I CALCULATION NO. 22S-B-004E 189 PROJECT NO.

4950 PAGE NO. 4 i-3 ASSUMPTIONS AND LIMITATIONS 4

None 4.

DESIGN INPUT -

4.1 Current LTOP setpoints

[5.4,1]

1PXX-403 407 psig 2PXX-403 407 psig 1PXX-405 407 psig 2PXX-405 407 psig P

is the bistable setting pressure where the Power Operated Relief Valves will open.

i P.,,,,,,, = 407 psig i

4.2 Transmitter Elevation Static Head The calibration of the RCS Wide Range Pressure Transmitters are not compensated for static -

head between their mounted elevation and the reactor core centerline [5.3.6, 5.3.7. 5.3.8, 5.3.9]. Three transmitters are mounted at 574' 2" and one at 574' 5"[5.4.1].

As depicted in Reference 5.4.2, the core centerline is at elevation 572' 9".

For purposes of conservatism, the largest static head will be used as the P. variable.

where p = 62.422 lbm/ft' at 65*F and 407 psig

[5.5.1]

A P,,; = (h _ _ - ha).p (572' 9"-574 '5"). 62422 %

ft*

a 144 in ft"

-1667 ft. 62422 h 1

(g3 1

2 144 in ft'

= -0.72 psi i

i 9

/

REVISION NO.

O

~

~

bvMMUINWVtAL I N RUlbON COMPANY CALCULATION NO. 22S-8-004E-189 PROJECT NO.

4950 PAGE NO. 5 l

4.3 PORV Overshoot The PORV Overshoot is the difference between the maximum RCS pressure reached while the PORV strokes open in response to a pr' essure excursion and the PORV setpoint.

The maximum RCS pressure reached is determined from data in Reference 5.2.4:

Setpoint PORV Open Maximum RCS Assumed Stroke Time Pressure Reached psig seconds (Pw) psig 400 2

442 4

450 500 2

542 4

548 The current LTOP Se'. point is 407 psig

[4.1]

The PORV Open Sttoke time is 3.4 seconds

[5.3.2, 5.3.3, 5.3.4]

It is first necessary to determine the maximum RCS pressure reached at 2 and 4 seconds fcr 407 psig through interpolation Max RCS Press @ 2 seconds = 542-442 * (407-400) + 442 500-400

=.449 psi

~

Max RCS Press @ 4 seconds =

• (407-400) + 450 500-400

45686 psi The maximum RCS pressure reached at 3.4 seconds is interpolated Max RCS Press @ 3.4 seconds

.8649 ('34-2) + 449 4-2

= 4545 psi l

AP

=P- % -P.

ov

= 454.5.- 407

= 47.5 psi 4.4 RCP/RHR Pump Operation Induced AP errors APpo,n, represents the dynamic headioss between the core centerline and the RCS hot legs.

Pump operations between 65'F and 70*F are limited by Reference 5.3.5 to one RCP and one RHR pump. AP errors induced by this pump combination is 22.6 psi [5.2.3].

AP,,,n, = 22.6 psi REVISION NO.

0 4

vvooviuoucut a ti culOUN LUMPAN Y CALCULATION NO. 22S-B-004E-189 PROJECT NO.

4950 PAGE NO. 6 i

4.5 Instrument Uncertainty The total loop uncertainty as calculated in Zion Calculation 22S-B-004E-166, "COMS/LTOP Pressure instrument Loop Accuracy Calculation"[5.2.1]

is 42.3 psi.

P.nno une.n% = 42.3 psi i

5.

REFERENCES.

5.1 METHODOLOGY 5.1,1 TID-Ell &C-10. " Analysis of instrument Channel Setpoint Error & Instrument Loop Accura Rev.0 5.1.2 TID-Ell &C-20, " Basis for Analysis of instrument Channel Setpoint Error & Loop Accuracy" Rev.0 5.1.3 American Society of Mechanical Engineers Cases of ASME Boiler and Pressure Vessel Code Case N-514, February 12,1992 5.2 CALCULATIONS 5.2.1 22S-B-004E-166 Rev. O, "COMS/LTOP Pressure Instrument Loop Accuracy Calculation" 5.2.2 Westinghouse Letter CWE-93-181, dated 10/4/93 " Commonwealth Edison Company Zion i

Units 1 & 2 Evaluation of COMS Analyses" 5.2.3 " Ibid., page 11, Table 3: Pressure Differentials Zion Units 1 and 2 5.2.4 lbid., page 16, Table 4: Pressure Overshoot Due to Mass injection Transients Zion Units 1 and 2 (Current Values) 5.3 ZION STATION PROCEDURES o

5.3.1 NEP 12.02, Rev. 2 " Preparation, Review, and Approval of Calculations" 5.3.2 PT-27A1-ST, Rev 4 " Pressurizer PORV and Block Valve Stroke Time Test With RCS Less Than 320*F" 5.3.3 PT-27A2-ST, Rev. 3 " Pressurizer PORV and Block Valve Stroke Time Test With RCS Greater Than 320*F" 5.3.4 PT-27A3 ST, Rev.'O " Pressurizer PORV and Block Valve Stroke Time Test With RCS Less Than 200*F" 5.3.5 GOP-1, Rev.10 " Plant Heatup" 5.3.6 IMTS-1P-403, Rev. O " Reactor Coolant Wide Range Pressure Transmitter" REVISION NO.

0 i

s e

~~

~ "~~ ~

COMMONWEALTH EDISON COMPANY CALCULATION NO. 22S-B-004E-189 PROJECT NO.

4950 PAGE NO. 7 5.3.7 IMTS-1P-405, Rev.1 " Reactor Coolant Wide Range Pressure Transmitter" 5.3.8 IMTS-2P-403, Rev.1 " Reactor Coolant Wide Range Pressure Transmitter" 5.3.9 iMTS-2P-405, Rev. O " Reactor Coolant Wide Range Pressure Transmitter" 5.4 ZION STATION DRAWINGS 5.4.1 Comed instrument Database (IDATA), Specific Data Sheet, and Supplemental Data Sheet for the following instruments:

1PT-403 Rev. D 1PXX-403 Rev. B 1PT-405 Rev. D 1PXX-405 Rev. B 2PT-403 Rev. C 2PXX-403 Rev. B 2PT-405 Rev. C 2PXX-405 Rev. B 5.4.2 M-9 Rev. E " General Arrangement Sections A-A & B-B Zion Station Unit No.1 & 2" 5.5 MISCELLANEOUS 5.5.1 A.S.M.E. Steam Tables J

h e

REVISION NO.

0

CALCULATION NO. 22S-B-004E-189 PROJECT NO.

4950 PAGE NO. 8 6.

CALCULATIONS This calculation will determine the minimum pressure to be used by Westinghouse to d new Appendix G Heatup/Cooldown curves cased upon the current LTOP setpoint.

The new RCS pressure will be designated as Pwo j

4 Per A.S.M.E. Code Case N-514 the LTOP system shall limit the maximum pressure in the vessel to 110% of the Appendix G Curve, therefore; Pm = 110% Pwo The LTOP setpoint is derived by; P,_, = P,,, - SP_ - APav-AP_ -P _ u _

t by substitution:

P,., = (110% F, o

) - AP, - APoy-AP_ -P _ %

2 i

p.o -. _ P_ + AP, + APa,+AP_ +P _ u 4

11 0 Substituting the design input values:

P.o-.

407 psig + (-0.72 psi) + 47.5 psi + 22.6 psi + 42.3 psi 4

1.10

= 47153 psig Ro'unded Pw a c,. = 472 psig 7.

SUMMARY

AND CONCLUSIONS The minimum acceptable Appendix G Curve Pressure, bdsed upon the current LTOP setpoint is 472 psig @ 65'F.

FINAL PAGE REVISION NO.

O

~

ee

Attachment C Westinghouse letter CWE-93-181, dated October 4,1993 i

h e%

Westinghouse Energy Systems 33 355 Electric Corporation

• *E' 4" Sea '530 C355 CWE-93-181 October 4.1993 Mr. E. A. Broccolo Commonwealth Edison Company Zion Nuclear Station 101 Shiloh Boulevard Zion. IL 60099 Commonwealth Edison Company Zion Units 1 & 2 Evaluationof COMS Analyses

Dear Mr. Broccolo:

The purpose of this letter is to transmit the report regarding the Cold Overpressure Mitigating System (COMS) at the Zion Station units.

If you have any questions or require further information on this' matter, please contact me.

Very truly yours, WESTINGHOUSE ELECTRIC CORPORATION

(~

~. -

C_..Y.fW}s_j,\\fl=L.-

N B. S. Ifumphries, Manager Commonwealth Edison Project Domestic Customer Projects Attachment N

Mr. E. A. Broccolo CWE-93-181 Page 2 October 4,.1993 cc:

Station VETIP Coordinator J. A. Johnson Zion K. A. Aingei Zion D. B. Wozniak Zion M. E. Lohmann Zion N. P. Mueller Energy Center S. M. DiTommaso Energy Center K..Wi Norris.

Zion 6

I ll

1 ZION UNITS 1 AND 2 REVISED COMS PORV SETPOINT ANALYSIS OCTOBER 1993 i

?

Revised PORV COMS (Cold Overpressure Mitigation System) setpoints have been determined for Zion Units 1 and 2. De setpoints have been developed over a range of PORV stroke times for various Effective Full Power Years (EFPY) of operation for both units 1 and 2. Major assumptions in their development are provided below.

t This COMS setpoint analysis has been performed in response to a nonconservatism identified after the previous setpoint development had been completed. He pressure difference from the reactor vessel midplane, where Appendix G Limits are defined, and the wide range pressure transmitter had not been considered which resulted in a higher RCS pressure at the midplane than that transmitted to actuate the PORVs. Rus, the potemial existed for violation of Appendix G Limits. This new analysis accounts for the pressure difference between the pressure transmitter and the reactor midplane. (See Table 2 of this document). As this nonconservative pressure difference is proportional to the number of reactor coolant pumps and residual heat removal pumps (RHRP) in operation, unique groups of setpoints are determined for 1,2 and 4 operating reactor coolant pumps, as well as 1 and 2 operating residual heat removal pumps.

Single setpoints for operating with reactor vessel exposures of 14, 20, 25 and 32 EFPY are presented over a range of primary PORV opening stroke times between 1 and 10 seconds.

i These maximum allowable setpoints are bounded by the steady state Appendix G limit at 85 deg F, without margin for instrument channel uncertainty either in the setpoint or the pressure temperature limit.

He evaluation does not consider the pressure limit associated with the number one reactor coolant pump seal limit.

4 Setpoints are generally evaluated following a comprehensive parametric analysis of Reactor Coolant System behaviour during one of two design transients under water solid conditions. The first is a mass injection transient characterized by loss of letdown, due to the spurious isolation of the residual heat removal system, concurrent with the failure of the charging flow controls to full flow. The second is a heat injection transient, resulting from the start of a reactor coolant pump when there is temperature asymmetry between the Steam Generators and the rest of the Reactor Coolt.nt System, the Steam Generators operating at the higher temperature. This causes heat transfer from the secondary to the primary side of the system.

The COMS Setpoint program for both Zion units is independent of RCS temperature, so that the single setpoint value is defined by the most limiting value of the pressure / temperature (Appendix G) limit at 85'F. Previous COMS analyses for Zion Units 1 and 2 have confirmed the dominance of the mass injection event at low temperatures (generally less than 150 deg F).

Therefore, overpressures caused by the mass injection transient form the basis for setpoint determination in this COMS/ evaluation (see Table 4). This is consistent with the 1990 Zion mm,nnen.umn 1

COMS setpoint evaluation which accounted for signal delays anticipated in the Eagle 21 digital protection system then being installed in both units for which the heat injection event was not-reanalyzed.

Assumptios;s and initial conditions of the mass injection design transient begin on page 12 of this report followed by limiting mass mjection rates. While the heat injection transient was not analyzed to account for Eagle 21 implementation, relevant assumptions and results of the 1986 COMS analyses are included for information along with the setpoint pressure overshoots. (See Tables 5 and 6). The Zion maximum charging flow for a single centrifugal charging pump is provided in Figure 7 and is consistent with the previous COMS analyses.

Maximum allowable setpoints for Zion Units 1 and 2 are provided in Tables 1 and 2. Figures 1-6 illustrate the maximum allowable setpoints versus PORV stroke time, for each vessel exposure period and number of RCPs and RHRPs in operation.

o 3407M SMD/Lts/1Cf3 2

I;

TABLE 1: ZION UNITS 1 AND 2 MAXIMUM ALLOWABLE LTOPS PORV SETPOINTS 1 RHRP PUMP IN OPERATION EFPY SETPOINTS (PSIG)

(Stroke Time) 1 PUMP 2 PUMPS 4 PUMPS 14 EFPY Stroke Time 1s 428 421 384 2

424 417 381 4

416 409 372 6

407 400 362 8

399 391 354 10 389 381 343 20 EFPY Stroke Time 1s 420 413 376 2

416 409 373 4

408 401 364 6

399 391 354 8

390 383 345 10 380 373 334 25 EFPY Stroke Time 1s 417 410 373 2

413 406 370 4

405 398.

361 6

395 388 351 8

387 380 342 10 377 369 331 32 EFPY Stroke Time 1s 413 406 369 2

409 402 366 4

401 393 357 6

391 384 346 8

383 376 338 10 373 365 326 3407M SMD/LE3/1093 3

TABLE 2: ZION UNITS 1 Ah3 2 MAXIMUM ALLOWABLE LTOPS PORY SETPOINTS 2 RHR PUMPS IN OPERATION EFPY SETPOINTS (PSIG)

(Stroke Time) 1 PUMP 2 PUMPS 4 PUMPS 14 EFPY Stroke Time 1s 425 418 381 2

421 414 378 4

413 406 369 6

404 3%

359 8

395 388 351 10 386 378 339 20 EFPY Stroke Time is 417 410 373 2

413 406 370 4

405 398 361 6

395 388 351 8

387 380 342 10 377 369 331 25 EFPY Stroke Time 1s 414 4'j7 3"O 2

410 403 307 4

402 394 358 6

392 385 347 8

384 377 339 10 374 366 328 32 EFPY Stroke Time 1s 410 403 366 2

406 399 363 4

398 390 354 6

388 381 343 8

380 372 335 10 369 362 323 3487M Sie/L28/1093 4

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l TABLE 3: PRESSURE DDTERENTIALS ZION UNITS 1 AND 2 P

i i

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Number of RCPs Delta P Delta P Delta P 1RHRP 2 RHRPs No RHRP 3

1 22.6 psi 25.5 psi 21.6 2

30.0 33.0 29.0 4

65.7 68.6 64.7 1

I

%e contributions of 1 and 2 RHRPs to the total delta P value are.97 psi and 3.89 psi, respectively.

4 l

s Assumptions:

1 i

Pressure drops were calculated between the mid core elevation in the reactor vessel downcomer region and the wide range pressure transmitter off of the RHR line, which is used as input to the

{

j Cold Overpressure Mitigation System at Zion Units 1 and 2. Other assumptions are as follows:

)

t j

1) 0% power RCS temperature of 70 'F RCS pressure of 500 psia j

2)

Steam generator tube plugging of 4.0%

(lower tube plucging yields the highest pressure drop) j 3) 102% of best estimate flow with 4 RCPs in operation. 100% of best estimate-i flow with I and 2 RCPs in operation 4)

Elevation difference between the middle of the core and the pressure transmitter is -1.14 feet.

5)

Averaged reactor coolant pump coefficients applied to each case i

i t

34stm sen.asnes s 11

i i

SPECIFICATIONS FOR MASS INJECTION TRANSEENT i

)

A parametric study was performed using constant mass injection rates between 100 gpm and 600 gpm. This range was sufficiently extensive to envelope RCS mass injection rates associated with the maximum possible injection rates from one charging pump following letdown isolation for the range of setpoints considered.

]

The mass injection design basis transient results from a sudden loss of letdown concurrent with i

the failure of the charging pump speed control to full flow. The allowable charging configuration with the LTOPS enabled, below an RCS temperature of 320 jeg F, is limited by technical 4

specification to a maximum of one charging pump aligned for ejection into the RCS.

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System /Opemting Pammeters i

a.

Temperatures Reactor Coolant System temperature is equal to 85 deg F.

1 b.

Reactor Coolant System Volume The RCS volume is conservatively assumed to be 12598.1 cubic feet for Zion Units 1 and 2.

c.

Initial Reactor Coolant System Pressure The initial RCS pressure is 200 psi less than the setpoint pressure.

d.

Reactor Coolant System Relief Capability The transient is analyzed for actuation of one power operated relief valve.

(Failure of one pressurizer PORV is assumed).

Power Operated Relief Valve Characteristics e.

1.

System behavior was analyzed for RCS pressure setpoints of 400,500,600 and 700 psig.

2.

Consistent with previous COMS methodology for Zion Units 1 aia 2.

PORV stroke times were assumed as follows:

24snaissenasness 12 w

1 Oornine Semke Tbne Clasine Simke Time f

1.0 s 0.97 s i

1.5 1.45 2.0 1.94 2.5 2.42 3.0 2.91 1

4.0 i

3.88 5.0 4.85 6.0 5.82 8.0 i

l 7.76 i

10.0 9.70 l

i

3. C, = 50 gpm/P" i

f i

j f.

Pressure Signal Transmission Characteristics He time delay from reachipg the setpoint presssure in the reactor coolant system l

until PORV motion is 1.15 maaA This does not include any delay from the surge withstand circuit identiSed by Commonwealth Edison as recently being j

installed with the Eagle 21. He 1990. Analysis shows that RCS pressure is

)

increasing at a rate of approximately 28 psi per second when the PORVs open i

during a mass injection transient of 400 gym. An additional delay of J.D.(fifty) 1 milliseconds would result in a pressure increase of only 1.4 psi. Herefore, an j

' additional delay of 5-10 milliseconds estimated by Rick Mason of CECO would j

have a negligible effect on'the results of the analysis.

I.

1 Results of the Mass Irjection Transient analysis are presented.in Table 4 which summarizes

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setpoint pressure overshoot and maximum RCS pressure reached for each case analyzed.

SPECIFICATIONS FOR HEAT 1NJECTION TRANSEENT j

While the design basis heat injection transient is not required for this particular setpoint evaluation, the assumptions are described below for informational purposes. These specifications apply to a 1986 COMS analysis, before Eagle-21 implementation.

j He transient results from the start of a reactor coolant pump with the existence of 50 deg F temperature asymmetry between the steam generator secondary side water and the water in the j

reactor coolant system. No credit is taken for residual heat removal system's relief valves.

t j

24stuimen.asness 13

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4 4

i 2

1 J

i j

a.

Temperature

1. Temperature asymmetry between primary and secondary side = 50 deg F.

2. Steam Generator (heat source) temperature = 120,150 and 200 deg F.

4 b.

Reactor Coolant System Volume The RCS volume is conservatively assumed to be 12598.5 cubic feet.

4 i

c.

Initial RCS Pressure i

l Initial RCS pressure is 315 psia, at least 100 psi less than any PORV setpoint pressure

]

used for the parametric study.

j f

d.

Pressurizer PORV Characteristics i

l 1.

System behavior was analyzed for RCS pressure setpoints of 400,500,600 and j

700 psig.

j i

I l

2.

Consistent with previoas COMS methodology for Zion Units 1 and 2, PORV

~

stroke times were usumed as follows:

l Ooenine Stroke Time Closine Stroke.Zime, t

i 1.0 s 0.97 s i

1.5 1.45 2.0 1.94 i

2.5 2.42 3.0 2.91 4.0 3.88 5.0 4.85 6.0 5.82 8.0 7.76 10.0 9.70 j

3. C, = 50 i

24e7msmiusnos 14~

4

. - _=-.- -.

1 Steam Generator Design e.

1.

Steam Generator tube heat transfer surface area = 51,500 square feet.

3 2.

Steam Generator type = Standard Model 51.

i f.

Pressure Signal Transmission Characteristics 4

h With the exception of the Eagle 21 contribution, the signal delay is the same as that for the mass injection case.

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TABLE 4: PRESSURE OVERSHOOT DUE TO MASS INJECTION TRANSIENTS i

ZION UNITS 1 AND 2 (CURRENT VALUES) 4 Setpoint Mass Injection PORY Stroke Time Maximu'.n RCS Assumed Rate Open Close Pressurce Reached' Rs)

&d i

400 psig 389.8 gpm 1.0 s 0.97 s 438 psig 2.0 1.94 442 4.0 3.88 450 3

3 6.0 5.82 459 8.0 7.76 467 10.0 9.73 476 500 psig 376.6 gpm 1.0 s 0.97 s

$36 psig 2.0 1.94 542 4.0 3.88 548 6.0 5.82 555 8.0 7.76 563 10.0 9.73 569 600 psig 369.6 gpm 1.0s 0.97 s 635 psig 2.0 1.94 638 4.0 3.88 645 6.0 5.82 651 8.0 7.76 659 10.0 9.73 664 700 psig 359.5 gym 1.0 s 0.97 s 733 psi 2.0 1.94 736 4.0 3.88 742 6.0 5.82 748 8.0 7.76 755 10.0 9.73 761

• Setpoint pressure overshoot = Pm - Ps newesenzanoss 16

1 4

j TABLE 5: PRESSURE OVERSHOOT DUE TO HEAT INJECTION EVENT l

ZION UNITS 1 AND 2 (FROM 1986 ANALYSIS, BEFORE EAGLE 21 IMPLEMENTATION) i Setpoint PORY Stroke Time Maximum RCS l

Assumed Open Close Pressure Reached *

(P )

1 (P.d 3

L/T.~ = 150/100*F L/ rom = 200/150*F l

i j

435 psig 1.0 s 0.97 s 455 psig 469 j

2.0 1.94 458 473 4.0 3.88 460 480 6.0 5.82

'464 487 l

8.0 7.76 468 495 10.0 9.73 472 504 i

500 psig 1.0 s 0.97 s 520 psig 533 t

2.0 1.94 522 537 4.0 3.88 525 545 6.0 5.82 529 553 l,

8.0 7.76 532 562 10.0 9.73 536 571 j

i 600 psig 1.0 s 0.97 s 620 psig 633 j

2.0 1.94 622 636

[

4.0 3.88 624 -

645 j

6.0 5.82 628 633 8.0 7.76 632 662 10.0 9.73 635 670 i

l 700 psig 1.0 s 0.97 s 719 psig 733 2.0 1.94 720 736 l

4.0 3.88 723 743

)

6.0 5.82 727 751 8.0 7.76 731 759 i

10.0 9.73 734 767

'Setpoint pressure overshoot = P. - P, l

j 3407Me sse/128/109 3 17 h

5 TABLE 6: PRESSURE OVERSHOOT DUE TO HEAT INJECTION EVENT (CONT'D)

ZION UNTIS 1 AND 2 (FROM 1986 ANALYSIS, BEFORE EAGLE-21 IMPLEMENTATION) i

^

Setpoint PORY Stroke Time Maximum RCS l

Assumed Open Close Pressure Reached

• j (P )

(pg s

L/T.,, = 120/70*F l

i 435 psig 1.0 s 0.97 s 447 1.5 1.45 449 2.0 1.94 448 2.5 2.42 449 3.0 2.91 450 l

500 1.0 0.97 513 i

1.5 1.45 513 2.0 1.94 513 j

2.5 2.42 514 l

3.0 2.91 514 d

600 1.0 0.97 611 1.5 1.45 612

~

2.0 L94 613 2.5 2.42 614 3.0 2.91 614 700 1.0 0.97 709 1.5 1.45 713 2.0 1.94 713 2.5 2.42 713 3.0 2.91 713

'Setpoint pressure overshoot = P. - P.

Note: The analysis was performed for the maximum PORV opening stroke time of 3.0 sec.

uewesen.xsnon 18 4

Figure 7: Zion Charging Flow at Indicated RCS Pressures 250c ggggy..g....g....g...

... g.. 4..... g.... p.. 4... 4... 4..... p.. 4....... +....y.. 4.... +....:... 4......:... 4..... ;... 4...

.oi

_ 15o,3 m

1

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100(F O

. - -- l --- - I - --- I -- -- I --.I - --- I - - -.I --- 4. --- 4. -- - I --- 4. - -- 4. -- - +. -- - +. - -- +. -- - +. - - - +. - -. - - - l 50(P C

1 175.8 210.3 241.1 268.1 293.4 316.4 338.8 359.5 379 6 399.4 418 9 156.1 193.7 226.3 254.7 281.1 305 327.7 349.3 369.6 389 8 409.2 429.3 O Injection (gpm)

l

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1 l

Attachment D Westinghouse Letter MSE-REME-0308, dated June 21,1996 l

i O

MSE-REME-0308, Revision /

Westinghouse Electric Corporation P. O. Box 355 Energy Systems Pittsburgh, Pennsylvania 15230-0355 June 21.1996 (412) 374-5438 Mr. Richard Skowzgird Commonwealth Edison Company Zion Station 101 Shiloh Blvd.

Zion. IL 60099

Subject:

Zion Units 1 & 2 Enable Temperature Calculations (includ'ng ASME i

Code Case N 514) 1 Westinghouse has updated the previous T-enable calculation provided under We:tinghouse letter CWE-92-244, dated August 1992. Please find attached the enable temperature calcultions using the methodology of NRC Standard Review Plan, Section 5.2.2 Overoressure Protection (NCREG-0800.

Revision 2). Rese results show that the enable temperature for Zion Units 1 and 2 is 345*F.

Additionally, per the request of the Commonwealth Edison (Comed) Company, Westinghouse calculated the enable temperature per the ASME Code Case N 514 methodology, although it is not yet approved. Therefore, also attached are the Code Case N-514 calculations which show that the enable temperature for Zion Units I and 2 is 305'F.

The latest limiting adjusted reference temperature (ART) values presented in WCAP-14664 were used in the calculations. Additionally, Comed has requested that the more realistic 60'F/hr values be used for calculating T-enable. His calculation did not consider temperature measurement uncertainty since this will be addressed by the Zion station.

This work was completed under a change notice to Customer Order No. 8151% (Westinghouse G.O.

WM-60176 OCS %10177), shop order number CEVP-139B.

If you have any questions or require additional information, please contact the undersigned.

Very truly yours, WESTINGHOUSE ELECTRIC CORPORATION L

Paula A. Grendys.

Reviewed By:

Ed Terek Reactor Equipment & Materials Reactor Equipment & Materials Engineering Engineering Attachment

Attachment to MSE-REME-0308, Revision /

The enable temperature was determined using the methodology from the following document since the N has not yet approved the methodology of ASME Code Case N-514:

NRC Standard Review Plan, Section 5.2.2, Overpressure Protection, NUREG-0800, Revision 2 November 1988, Branch Technical Position RSB 5-2, Overpressure Protection of Pressuri ed Water Reactors While Operating at Low Temperatures, Revision (, November 1988.

Enable Temperature = RTsor + 90 + max ( ATJ, F I

where, RTsor is either the 1/4T Adjusted Reference Temperature (ART) or the 3/4T ART 1

AT,,,,

is the temperature difference between RCS water and either the 1/4T or 3/4T metal temperature at the controlling location He following calculations were completed using the latest curves documented in WCAP-14664, Zion Units /

and 2 Heatup and Cooldown Limit Curvesfor Normal Operation, dated June 1996.

Per WCAP-14664, the Zion Units I and 2 ARi values are:

1/4T ART = 233.0*F 3/4T AR T = 183.3'F From the fiche OPER010 (Configuration #5685883132544) of Calc Note REME-%-040, Zion Units I and 2 HU/CD Curves Applicable to 32 & 25.63 EFPY, Respectively, P. A. Grendys, dated 5/30/96:

Cooldown Rate (Steady-State Cooldown):

max ( AT,,,,w) at 1/4T = 0'F max ( AT,,,,w) at 3/4T = 0'F Heatup Rate of 60*F/Hr:

max ( AT,,,, ) at 1/4T = 17.660*F max ( ATow) at 3/4T = 36.886'F Enable Temperature (ENBT) = RTuo. + 90 + max (AT,,.), 'F l

Cooldown Rate (Steady-State Cooldown) :

ENBT at 1/4T = 233.0 + 90 + 0 = 323.0*F 3

ENBT at 3/4T = 183.3 + 90 + 0 = 273.3*F i

Heatup Rate of 60*F/Hr:

ENBT at 1/4T = 233.0 + 90 + 17.660 = 340.660'F ENBT at 3/4T = 183.3 + 90 + 36.886 = 310.186'F j

nerefore, a conservative enable temperature of 345'F shall be used in determining the LTOP system serpoints since this value bounds all possible cases during heatup and cooldown.

9

6 Attachment to MSE REME-0300, Revision /

ASME CODE CASE N-514 ASME Code Case N 514 allows low temperature overpressure protection systems (LTOPS, as the code refers to COMS) to limit the maximum pressure in the reactor vessel to 110'7c of the pressure determine satisfy Appendix G, paragraph G-2215, of Section XI of the ASME Code. The application of ASME Code Case N-514 increases the operating margin in the region of the pressure-temperature limit curves where t COMS system is enabled.

Although expected soon, use of Code Case N 514 has not yet been formally approved by the NRC. In the interim, an exemption to the regulations must be granted by the NRC before Code Case N-514 can be used the determination of the COMS setpoints and enable temperature.

\\

Code Case N-514 requires LTOPS to be effective at coolant temperatures less than 200*F or at coolant temperatures corresponding to a reactor vessel metal temperature less than RTsor + 50*F, whichever is grea RTsor is the highest adjusted reference temperature for weld and base metal in the beltline region at a dis one-fourth of the vessel section thickness from the vessel inside surface, as determined by Regulatory Gu 1.99, Revision 2.

Per WCAP-14664, the Zion Units 1 and 21/4T ART value is 233.0*F.

Enable Temperature = RTm + 50 + max ( ATJ, 'F

= 233 + 50 + 17.660 = 300.660*F Therefore, a conservative enable temperature of 305'F shall be used in determining the LTOP system setpoints.

e e

e

e I

f 1

i Attachment E Zion Calculation No. 22S-B-004E-192, Revision 0

.