ML20207A338
| ML20207A338 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/19/1999 |
| From: | Alexion T NRC (Affiliation Not Assigned) |
| To: | NRC (Affiliation Not Assigned) |
| References | |
| TAC-MA3519, NUDOCS 9905260272 | |
| Download: ML20207A338 (14) | |
Text
l lY)a 11,
/fif MEMORANDUM TO:{We$3 FROM:
Thomas W. Alexion, Project Manager, Section 1 Project Directorate IV & Decommissioning Division of Licensing Project Management
SUBJECT:
DISCUSSIONS WITH LICENSEE ON ITS FUTURE SUPPLEMENT TO APPLICATION ON COLD OVERPRESSURE MITIGATION CURVE ASSOCIATED WITH REPLACEMENT STEAM GENERATORS (TAC NOS. MA3519 AND MA3520)
The U. S. Nuclear Regulatory Commission (NRC) staff has had discussions with the licensee on its August 31,1998, application for a license amendment to Technical Specification 3.4.9.3 to reflect a revised cold overpressure mitigation curve associated with the replacement steam generators. This application was supplemented by letter dated April 19,1999. The licensee is planning another supplement and has requested further discussions with the NRC staff.
In order to facilitate future discussions between the licensee and the staff, the licensee provided the information in the attachment. The licensee has informed me that this information is preliminary and it plans to follow-up this information with a formal submittal. The purpose of this mernorandum is to place the attachment in the Public Document Room.
Docket Nos. 50-498 and 50-499
Attachment:
As stated I
hf DISTRIBUTION:
Docket i iles (50-498 arjd 50;499)3 PUBLIC DOCUMENT NAME: G:\\Pdiv-1 \\SouthTexas\\M EMA3519.W P D To receive a copy of thes document. Mdrete M the bow C= Copy w'O 8ttachment/ enclosure E. Copy with attachment / enclosure N = No copy OFFICE PDtV:T/Pid E
PDIV-D/LA E
NAME TAlexio CJamerson d/
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DATE b /
/99 6 /18 /99 OFFICIAL RECORD COPY yol c.~
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May 19,1999 MEMORANDUM TO: File FROM:
homas W. Alexion, Project Manager, Section 1 Project Directorate IV & Decommissioning Division of Licensing Project Management
SUBJECT:
DISCUSSIONS WITH LICENSEE ON ITS FUTURE SUPPLEMENT TO APPLICATION ON COLD OVERPRESSURE MITIGATION CURVE.
ASSOCIATED WITH REPLACEMENT STEAM GENERATORS (TAC NOS. MA3519 AND MA3520)
The U. S. Nuclear Regulatory Commission (NRC) staff has had discussions with the licensee on its August 31,1998, application for a license amendment to Technical Specification 3.4.9.3 to reflect a revised cold overpressure mitigation curve associated with the replacement steam generators. This application was supplemented by letter dated April 19,1999. The licensee is planning another supplement and has requested further discussions with the NRC staff.
In order to facilitate future discussions between the licensee and the staff, the licensee provided the information in the attachment. The licensee has informed me that this information is preliminary and it plans to follow-up this information with a formal submittal. The purpose of this memorandum is to place the attachment in the Public Document Room.
Docket Nos. 50-498 and 50-499
Attachment:
As stated
e South Texas Projea STP Electric Generating Station Nuclear Operating Company Boz289 N5014 Wadswanh, TX 77483,
Date:
hiay 17,1999 Number of pages including cover sheec 12 l
To: Tom Alexion, NRC/NRR From: Mr.rk Van Noy, Nuclear Licensing South Texas Project Nuclear Operating Company Phone:
301 415 1326 Phone 512 972 7336 Pax phone:
301-415-3061 Fax phone:
512-972-8298 CC-Pater:
409 239-6474 REMARKS:
O Ursent O Poryourreview O Reply ASAP O Please comment FOR: TOM ALEXION Here are the marked up pages for the DRAFT of our revision to our COMS submittal (NOC-AE-0203), of 8/31/98, that is currently under review by NRC stafE They demonstrate the effects of:
e Reinstatement of a surveillance for Charging Pumps - Shutdown e Addition of a new surveiBance for AccumulatorI4ckout (per ISTS) e Changes to COMS maximum aDowable setpoint calculation methodology of WCAP-13782 to make it conform to NRC approved methodology of WCAP-14040
- 1. Addition of a calculated value for pressure instrument uncenainty (-48.6 psig)
- 2. Application of AShE Section XI Code Case N 514 (+62.1 psig)
Attachment
,11AY-17-8999 84:5kB QM2L:i24 Ll(@ M8Cfg b N.tdvis NOC-AE.-
Anachment 4 Page 1 of 7 ATTACHMENT 4 i
I TECHNICAL SPECIFICATION J
MARKED-UP PAGES
eunmn-ras vnes NOC-AB-A,tw& ment 4 Pase 2 cf 7 PROPOSED CHANGES TO TFCHNICAL SPECIFICATIONS Techmca1 Specification Pages 3/4 4-36 and 3/44-38 are marked up to identify the proposed changes and are included in this attachment with new insens. (NOTE: Technical Specification Page 3/4 4-37 is Pigure 3.4-4.) Technical Specification Bases page B 3/4 4-15 is aho marked-up to indicate change. Bases pages B 3/4 4-14 and B 3/4 4-14a are included for reference, but contain no changes.
Insen the foBowing text into the attached marked-up T-h=W Specification pages, as indicated:
INSERT 1 with a maximum of one centrifugal charging pump capable ofinjecting into the RCS and the accumulators isolated and either a. or b. below INSERT 2 a.
With one or more accumuhtors not isolated, isolate the accumulator (s) within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, b.
With more than one centrifugal charging pump capable ofinjecting into the RCS, immediately initiate action to render aH but one centrifugal charging pump incapable of injectinginto the RCS*.
INSERT 3 4.4.9.3.4 Verify that only one centrifugal charging pump is capable ofinjecting into the RCS* at least once every 31 days, except when the reactor vessel head is removed, by verifying that the motor circuit breakers are secured in the open position'.
INSERT 4 4.4.9.3.5 Verify that each accumuhtor is isohted at least once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
INSERT 5 1.
Accumuhtor isohtion is only required when accumulator pressure is greater than or equal to the maximum RCS pressure for the existing RCS cold leg temperature allowed by Pigures 3.4-2 and 3.4-3.
INSERT 6 2.
For 515 minutes during pump swap operations, two centrifugal charging pumps may be capable ofinjecting into the RCS.
INSERT 7 while makmg au but one centrifugal charging pump incapable ofinjecting into the RCS pursuant to Technical Specification 4.4.9.3.4, and
N W9a93 M T AcL%2We BWf5nfA:SR:T-TQf47Z3 NOC-AD Arinchment 4 Page 3 af 7 INSERT 8 all but one centdfugal charging pump is made incapable of injecting into the RCS, and INSERT 9 An inoperable centrifugal charging pump (s) snd/or positive disphcement charging pump may be energized for testing provided the discharge of the pump (s)
INSERT 10 Reactor Coohnt Pump sealinjection flow may be maintained dudng the RCS isohtion process.
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INSERT 11 The Technical Specifications also require accumuhtor isohtion when accumuhter pressure is greater than or equal to the maximum RCS pressure for the existing RCS cold leg temperature j
allowed by Figures 3.4-2 and 3.4 3.
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Auachacet4 Page 4 of 7 REACTORCOOLANTSYSTEh!
OVERPRES$URE PROTECTION $YSTEMS LIMITING CONDITIDH FOR OPERAT10N Aw 27 th: f;".:abg)verpressure Protection Syste[shall 3.4.9.3 at *::: :::
be OPERABLp lussar1 Two power-operated relief valves (PORVs) with lift settings which a.
do not exceed the limit established in Ngure 3.4-4, or b.
The Reactor Coolant System (RC$) depressurized with an RCS vent ol' greater than or equal to 2.0 square inches.
APPLICABILITY: H0 DES 4 and 5, and MODE 6 when the heed is on the reactor vesset Nh sIIs Lasar2 With one PORY inoperable in H0DE 4 restore the inoperable PORY to l
f.
OPERABLE status within 7 days or depressurize and vent the RC5 C.
through at least a 2.0 square inch vent within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
With one PORY inoperable in H00E5 5 or 6 with the head on the reactor
)d(. vessel, restore the inoperable PORY to OPERABLE status within 24 l
hours or complete depressurizatica and venting of t through 8
at'le st a 2 square inch vent within the next 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
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f.
With both PORVs inoperable, depressurize and vg g e RCS through
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at least a 2.0 square inch vent within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
f, In the event either the PORVs or the RCS vent (s) are used to mitigate jf.'
an RCS pressure transient, a special Report shall be prepared and f
submitted to the Commission pursuant to Specification 6.9.1 within 30 days. The report shall describe the circumstances initiating the transient, the effect of the PORVs or RCS vent (s) on the transient, and atiy corrective action necessary to prevent recurrence.
f.
The provisions of Specification 3.0.4 are not applicable.
l S'
Mis ACTION may be suspendad for up to 7 days to allow functional testing to y
verify PORV operability. During thic test period, operation of systems or components which could result in an RCS mass or temperature increase will be administrative 1y controlled. During the ASME stroke testing of two inoperet,le Ramrs PORVs, cold overpressurization mitt 0ation will be provided by two RHR discharge r [-g relief valves associated with two OPERABLE and operating RHR loops which have the auto closure interlock bypassed (or deleted). If one PORY is inoperable.
Ps M4 38 cold overpressure sitigation will be provided by the OPERABLE PORV and one RNA discharge relief valve associated with an OPERABLE and operating RHR loop which has the auto closure interlock bypassed (or deleted).
s.
Unit 1 " Amendment No. 31 W W vevat - UNITS 1 (, 2 3/4 4-36 BnM R - b. 3wt it-22
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200 400 TRTD - AUCTl0NEERED LDW WEASURED RCS TEWPERATURE F) imes ENW 4 PUWP OPDtA o-tossono m FIGURE 3.4-4 NOMINAL MAXIMUM ALLOWABLE PORY SETPOINT FOR THE COLD OVERPRESSURE SYSTEM SOUTH TEXAS - UNITS 1 & 2 3)44-37 Unit 1 - Amendment No. 63 Unit 2 - Amendment No. 52
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MAXIMUM ALLOWABLE PORY SETPOINT 1
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NOC-AEJ Anadment 4 Page7 of 7 REACTOR COOLANT SYSTEM OVERPRESSURE PROTECTION SYSTEMS
$0RVFILLANCE REOUTREMENTS 4.4.9.3.1 Each PORV shall be demonstrated OPERABLE by:
a.
Performance of an ANALOG CHANNEL OPERATIONAL TEST on the PORV actuation channel, but excluding valve operation within 31 days priortoenteringaconditioninwhichthePORVIsrequiredOPERABLE and at least once per 31 days thereafter when the PORY is required OPERABLE; b.
Performance of a CHANNEL CALIBRATION on the PORV actuation channel at least once per 18 months; and c.
Verifying the PORV block valve is open at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> when the PORV is being used for overpressure protection.
o' 4.4.9.34The RCS vent (s) shall be verified to be open at least once per v
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when the vent (s) is being used for overpressure protection.
4.4.9.3.3. The positive displacement pump shall be demonstrated inoperabib at least once per 31 days, except when the reactor vessel head is removed,
or when both centrifugal charging pumps are inoperable and secured, by v
verifying that the motor circuit breakers are secured in the open position.****
InsEAr b IuSEltr Y L
Iwuers Laar Setememow Nornous
[or otherwise secured in the open position, then verify these valves open at A
cept when the vent pathway is provided with a valve which is locked, sealed.
east once per 31 days.
g, he provisions of 3.0.4 and 4.0.4 are not applicable for entry into MODE 4 runer7_ fr m MODE 3 for the positive displacement pump declared inoperable pursuant 4
to Specification 4.4.9.3.3 provided that the positive displacement pump is gg A
t.
declared 6NOPERABLElwithin 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> after entry into MODE 4 from MODE 3 or c '*
prior to the temperature of one or more of the RCS cold legs decreasing gelow325'F,whichevercomesfirst.
.y g
.h:4:4f tiv; di:;t;;r;;nt pu:; ::- b: cr.;r;;i::d f r t:: ting provided the p;qNhas been iEolated from the RCS by a closed isolation
'"':n:r : :: 2:
valvewIthpowerremovedfromthevalveoperator,orbyamanualisolation
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valvesecuredintheclosedposition.i ruscar 10 SOUTH TEXAS - UNITS 1 & 2 3/4 4-38 Unit 1 - Amendment No. 4
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- Beamir19A9FaMs enz snan:ses nt4griIg NOC AE '
At:achment 5 Page l of 4 1
l ATTACHMENT 5 TECHNICAL SPECIFICATION BASES MARKED-UP PAGES e
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REACTOR COOLANT SYSTEM BASES PRESSURE / TEMPERATURE LIMITS (Continued)
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increase with increasing heatup rate, a lower bound curve cannot be defined.
Rather, each heatup rate of interest must be analyzed' on an individual basis.
Following, the generation of ' pressure-temperature curves for both the steady-state and finite heatup rate situations, the final limit curves are produced as follows.
A. composite curve is constructed based on'a' 4y -
point comparison of the steady-state and finite heatup rate data ? point At'any given temperature, the allo rable pressure is t~aken.to be the lesser of the three values taken from the curves under considerationd : -
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The use of the composite curve is necessary to set conservative heatup limitations because it is possible for conditions to exist such that over the course of the heatup ramp,,the contr61.lin.g, condition s)< itches fr.cm the. inside. -
to the outside a'nd the pressure liniit must at all times be based on analysis of the most critical criterion.
Finally, the composite curves.-for the heatup-rate : dataand'the cooldown rate data are adjusted for possible errors in the pressure and temperature sensing instruments by the values indicated on the respective curves.
- g-Although the pressurizer operates in temperature ranges above those for which there is reason for concern of nonductile failure, operating limits are provided to assure compatibility of operation with the fatigue analysis performed in accordance with the ASME Code requirements.
LOW TEMPERATURE OVERPRESSURE FROTECTION The OPERABILITY of two PORVs or an RCS vent opening of at least 2.0 square inches ensu'res that the RCS will be protected from pressure transients which could exceed the limits of Appendix G to.10 CFR Part 50 when one or more of the RCS cold legs are less than or equal to 350*F. Either PORV has 1
adequate relieving capability to protect the RCS from overpressurization when the transient is limited to either: (1) the start of an idle RCP with the secondary water temperature of the steam generator less than or equal to 50'F above the RCS cold leg temperatures, or (2) the maximum credible mass injection flow rate due to the startup of a single HHSI pump plus 100 gpm net charging flow, while the RCS is in a water solid condition and the RCS temperature is between 350*F and 200*F.
For RCS temperatures less than 200*F, the maximum overpressure event consists of operating a centrifugal charging pump with complete termination of letdown and a failure of the charging flow control valve to the full flow condition.
l SOUTH TEXAS - UNITS 1 & 2 B 3/4 4-14 Unit 1 - Amendment No. -4, 62 Unit 2 - Amendment No. 51
-m w.ms~nsmenn i ennmn-rw-r wnscem NOC AE i O [/IANGfS
/s s,E Page 3 oN REACTOR COOLANT SYSTEM BASES LOW TEMPERATURE OVERPRESSURE PROTECTION (Continued)
The design mass input transient in MODE 4 assumes that, with failure of one PORV to open, a safety injection signal will start one High Head Safety The normal charging and letdown flow paths would be isolated by a containment isolation phase "A" signal, but a Reactor Coolant Pump seal Injection pump.
The flow rate of 100 gpm would be maintained (normal seal flow is 20 gpm).
capacity of each PORV is sufficient to discharge the combined High Head Safety Injection and Reactor Coolant Pump seal flow rate at RCS pressure below the In MODE 5, the present maximum allowable PORV setpoint pressure for 200*F.
mass input transient assumes the operation of one Centrifugal Charging Pump In (CCP) with letdown isolated and the charging flow control valve full open.
each case the letdown is isolated allowing only the path through the RCP seals Whether one or both CCPs are lined up to with a maximum CCP flow of 100 gpm.
the RCP seal flow path, the credible flow through the RCP seals can only be 20 Therefore, by gpm with letdown isolated unless a seal failure occurs.
positioning the charging isolation valve closed during a pump testing or switching process, assurance is provided that a mass additional pressure transient, which exceeds the relief capacity of a single PORV, will not occur.
The Maximum Allowed PORY Setpoint for the Cold Overpressure Mitigation System (CONS) is derived by analysis which models the performance of the COMS assuming various mass input and heat input transients. Operation with a PORV Setpoint less than or equal to the maximum Setpoint ensures that Appendix G criteria will not be violated with consideration for a maximum pressure SOUTH TEXAS - UNITS 1 & 2 B 3/4 4-14a Unit 1 - Amendment No. 62 i
Unit 2 - Amendment No. 51
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1FP148 NOC.AE-A,'*A =nt5 Pge4 cf 4 REACTOR COOLANT SYSTEM BASES LOW TEMPERATURE OVERPRESSURE PROTECTION (Continued) overshoot beyond the PORV Setpoint which can occur as a result of time dela s in signals processing and valve opening, instrument uncertainties, and si failure. To ensure that mass and heat input transients more severe than ose assumed cannot occur. Technical Specifications require lockout of all high head safety injection oumas while in MODE 5 and MODE 6 with the reactor vessel head on. All but one higs head safety injection pump are required to be locked out in H0DE 4.
Technical Specifications also require lockout of the positive displacement pump and all but one charging pump while in MODES 4. 5.
and 6 with the reactor vessel head installed and disallow start of an RCP if secondary temperature is more than 50*F above primary temperature.3 ruspy [1 Administrative controls and two RHR relief valves will be used to provide cold overpressure protection (COMS) durine the ASME stroke testing of two administrative 1y declared inoperable PORVs. 6uring the perfonnance of the PORV function test. two RHR trains will be OPERABLE and in operation with the auto closure interlock bypasses (or deleted) to provide COMS.
the OPERABLE PORV and one RHR relief valve associated with' g the ASME t With one PORV inoperable. COMS will be provided durin an OPERABLE and operating RHR train which has the auto closure interlock bypassed (or deleted). Each RHR relief valve provides sufficient capacity to relieve the flow resulting from the maximum charging flow with concurrent loss of letdown.
Analysis conservatively demonstrates that the RHR relief valves limit RCS pressure to approximately 590 psig.
Therefore two OPERABLE and operating RHR trains,qt one OPERABLE PORV and one OPERABLE and operating RHR train will provide adequate and redundant overpressure protection. Use of the RHR relief valves will maintain the RCS pressure below the low temperature limits of ASME Section III. Appendix G.
l 1
With regard to the MODE 6 applicability of this Technical Specification.
the statement "with the head on the reactor vessel" means any time the head is installed with or without tensioning the RPV studs.
The Maximum Allowed PORV Setpoint for the COMS will be updated based on the results of examinations of reactor vessel material irradiation surveillance specimens performed as required by 10 CFR Part 50. Appendix H.
)
3/4.4.10 STRUCTURAL INTEGRITY - BASES The inservice inspection and testing programs for ASME Code Class 1. 2.
and 3 components ensure that the structural integrity and operational
-readiness of these components will be maintained at an acceptable level f
SOUTM TEXAS - UNITS 1 & 2 B 3/4 4 15 Unit 1 - Amendment No. 4. 36, 65 1119-97
)
Unit 2 - Amendment No. N. 44 1119 97 TOTAL P.12 i
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