ML20203P737
| ML20203P737 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/02/1986 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| IEIN-84-09, IEIN-84-9, NUDOCS 8605080090 | |
| Download: ML20203P737 (34) | |
Text
.
TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374o1 SN 157B Lookout Place May 2, 1986 Director of Nuclear Reactor Regulation Attention:
Mr. B. Youngblood, Project Director PWR Project Directorate No. 4 Division of Pressurized Water Reactors (PWR)
Licensing A U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Youngblood:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 By the December 18, 1984 letter from J. A. Domer to E. Adensam, we requested a deviation to the NRC staff position requiring the installation of reactor coolant system cold leg temperature (Teold) instrumentation in the auxiliary control room (ACR) of the Sequoyah Nuclear Plant (SQN). Additional information was provided to NRC by the March 19, 1986 letter from me to you.
As discussed in the April 9,1986 telephone conversation with the NRC staff, in which NRC agreed to reevaluate their position, enclosed is additional information to be used with our previous submittals as a justification for the deviation request to not install reactor coolant system T in the ACR at SQN.
eold instrumentation If you have ar.y questions regarding this subjection, please call Jerry Wills at FTS 858-2683 Very traly yours,
!TJNESSEE VALLEY AUTHORITY
/
R. L. Crldley Director Nuclear Safe and Licensing Enclosure cc (Enclosure):
U.S. Nuclear Regulatory Commission Region II Attn:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. Carl Stahle Sequoyah Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 B605080090 860502
. sol PDR ADOCK 05000327
'y PDR (i,
I An Equal Opportunity Employer I __
m a
h ENCLOSURE TVA JUSTIFICATION FOR APPENDIX R DEVIATION REQUEST TO NOT INSTALL REACTOR COOLANT SYSTEM COLD LEC TEMPERATURE (TCOLD IN THE AUKILIARY CONTROL ROOM SEQUOYAH NUCLEAR PLANT DOCKET NOS. 50-327 AND 50-328 O
l l
l l
l l
l l
TA9LE OF CONTENTS EXECUTIVE
SUMMARY
I.
History II.
TVA Position III. Auxiliary Control Room
~
A.
Unique ACR Features B.
Instrumentation and Controls Available in ACR C.
Comparison with OIE Information Notice 84-09 Requirements D.
TVA Experience in Plant Shutdown from ACR IV.
Natural Circulation Verification Instrumentation in ACR Instrumentation / Indications Available to Verify Natural o
Circulation o
SQN Emergency Operating Instruction ES-0.3 o
Westinghouse Owner's Group ERGS V.
Cost of T Modifications A.
Installation costs B.
ALARA Considerations C.
Consideration of Other Options VI.
S/G Pressure Instrumentation Adequacy to Infer T SQN/Diablo Canyon Naturel Circulation Test Results o
o S/G Pressure versus T Time Lag Comparison of Appendix R Shutdown Equipment to Normal o
Shutdown Equipment VII.
Summary and Conclusions VIII. Sequoyah/Diablo Canyon Natural Circulation Graphs,
1 NOMENCLATURE ACR Auxiliary Control Room ACCUM Accumulator AFW Auxiliary Feedwater ALARA As Low As Reasonably Achieveable BA Boric Acid BD Board Bys Bypass CCS Component Cooling System CLR Cooler Cntmt Containment CVCS Chemical and Volume Control Systems cont Controller CRDM Control Rod Drive Mechanism Det Detector DR Drain EI Voltage Indicator ERCW Essential Raw Cooling Water ERG Emergency Response Cuidelines ES Emergency Instructions Exch Exchanger FI Flow Indicator Ht Heat HtX Heat Exchanger Hde Header HIC Hand Indicating Controller HS Hand Switch Inj Injection Isol Isolation kV Kilo Volt LOCA Loss of Coolant Accident LI Level Indicator LIC Level Indicator Controller MCR Main Control Room MOV Motor Operated Valve PI Pressure Indicator PIC Pressure Indicator Controller Pmp Pump PRT Pressurize Relief Tank Press Pressure PW Primary Water Pwr Power Regn Regenerative RCDT Reactor Coolant Drain Tank RCP Reactor Coolant Pump RCS Reactor Coolant System RHR Residual Heat Removal RM Radiation Monitor SD Shutdown S/G Steam Cenerator SIS Safety Injection System SUP Supply NOMENCLATURE SW '
Switch T,TCL, Teold - RCS Cold Leg Temperature e
T.THL, Thot - RCS Hot Leg Temperature h
TI Temperature Indicator Tk Tank Trf Transfer Tsat Steam Generator Saturation Temperature V-Volt Viv Valve Vol Volume WDS Waste Disposal System XS Transfer Switch N
4 a
f l,
l l
L
EXECUTIVE
SUMMARY
Installation of T nstrumentation in the auxiliary control room was eold identified in OIE Information Notice 84-09 as guidance for compliance with Appendix R requirements. After a thorough review of the concerns associated with installation of additional T eold interaction with NRC, TVA's position remains that the facts support our position that installation of additional T instrumentation in the Id auxiliary control room is not justified based on the following:
o Adequate assurance is provided that the plant can achieve and maintain a safe shutdown condition and this assurance is based on o
uniqueness of SQN ACR design o
large amount of instrumentation / controls available for shutdown from the ACR o
Experience / training in plant shutdown from the ACR o
ACR instrumentation for natural circulation that conforms to WOG ERG guidelines o
Installation and exposure cost of $3.9 million dollars ALARA considerations which show a 50 PERCENT increase in total o
station personnel exposure for the year that installation occurs.
Adequacy of steam generator pressure instrumentation to infer T o
eold
_4_
4 o
Increased probability of.a small break LOCA as a result of four additional penetrations to the reactor coolant system.
l Therefore, we believe that a deviation is justified to the NRC guidance l
contained in OIE Information Notice 84-09.
e 9.
ENCLOSURE I.
HISTORY There has been a considerable history of submittals and discussions associated with the adequacy of TVA's use, in the Auxiliary Control Room (ACR), of S/G T,,
to infer T and thus, to provide for an indication of natural circulation. While the majority of this activity has been on the Watts Bar docket, the issue and TVA's position is common to both Watts Bar (WBN) and Sequoyah (SQN).
The NRC staff first raised the question concerning T n March 25, d
1983 in a letter on the WBN docket.
This letter took issue with TVA's position that T c u d be inferred from T TVA responded on eold sat.
June 17, 1983 with the data that had been gathered during the SQN start-up tests. This test data illustrated that T,,
did indeed track T
and thus, provided adequate input to the ACR for confirmation of d
natural circulation. A documented NRC response to that submittal was never received.
In late 1984 and early 1985, as part of the Appendix R reevaluation of both SQN and WBN, TVA identified the lack of T in the ACR as a od deviation to NRC's guidance contained in Information Notice 84-09.
As justification for the deviation to Information Notice guidance, we reiterated our position as originally stated in the 1983 submittal.
The results of the start-up test at SQN formed the basis for our position...
l
\\
A3 a pirt of ths pracars to rssolvs outotending licanzing iscuss et WB2, a meeting was held with NRC on March 7, 1985 to discuss T and other Id fire protection issues. The advantages and disadvantages of using T,,
in lieu of T were scussed between TVA and NRC.
NRC requested cold that TVA review the upcoming Diablo Canyon test-to obtain additional supporting information.
Results from the Diablo Canyon test were obtained and analyzed during the summer of 1985. The results, along with information on operator usage of T
Procedures, stratification and training were submitted on the WBN sate docket on September 26, 1985 and on the SQN docket on March 19, 1986.
NRC subsequently notified TVA that there was insufficient information presented to resolve the T question. TVA agreed to supply eold additional information.
In a subsequent telephone conversation between TVA and NRC on April 9, 1986, several issues were discussed, among which it was noted that our previous submittals ha?.. focused upon correlation of T,,
versus Teold and had not provided a broader picture of the unique nature of the TVA ACR, the complexity, cost, and man-rem exposure of installing T d'
and the amount of existing instrumentation available to the TVA operators. We also noted that TVA previously may not have clarified the f act that the following instrumentation and controls are available in the ACR.
1.
T f r all f ur RCS loops hot 2.
SG pressure (and thus, T,,) for all four SG, 3.
the ability to feed all four steam generators.
TVA POSITION TVA's position remains essentially unchanged with respect to the need for T
in the ACR. However, based on our telephone conversation on April 9, 1986 it should be pointed out that this position is based on much more than the tracking of T by T,
The position is heavily influenced by the unique plant ACR and backup control systems found in the SQN plant design, the emergency response guidelines developed by the Westinghouse owners' Croup, the cost, and the complexity of installing T coid It is TVA's position that when the following factors are better understood and are taken into consideration, that there exists adequate instrumentation and controls to safely achieve and maintain safe shutdown; Unique ACR Design o
Level of Control and Instrumentation available in the ACR (and the o
adjacent shutdown board rooms) o WOG recommendations Plant procedures and training on ACR o
Accuracy of T,,
to infer T o
The benefits. if any, to be gained by installing T n
e CR do not eold offset:
o Cost of adding Teold o
Man-rem exposure to install T d
Lon5-term maintenance and ALARA considerations o
Increased probability of a small break LOCA as a result of four o
additional penetrations to the RCS.
III. Auxiliary centrol R?om (ACR),
A. In order to address situations requiring evacuation of the control building, TVA's original design provided for an auxiliary control system for SQN. This system is located outside of the control building and is totally independent of the control building (MCR, auxiliary instrument rooms, cable spreading room, and others). The design has the capability to provide an appropriate means to. isolate the necessary safe shutdown equipment and control features from the control building.
The principle feature of this system is the auxiliary control room complex. The complex is divided into five independent, dedicated rooms, each separated from the other and from the auxiliary building by 1-1/2-hour compartmentation and from the control building by 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> compartmentation. The five independent rooms consist of feur transfer switch rooms and a auxiliary control room containing multiple instrumentation and control panels.
The auxiliary control room is designed to be the central control point when operating in the auxiliary control mode. Systems requiring frequent manipulations have the necessary controls located in the ACR along with their associated transfer switches located in the adjacent transfer switch rooms. Adequate instrumentation is provided for monitoring conditions of the plant.
Listed below are the instruments and controls found in and immediately adjacent to the ACR... -
B. In-trument*tien rnd C*ntrols Av'ilable Fer Shutdown from th7 Auxiliary Control Room (ACR)
B.1 The following listing of instrumentation is located in the Auxiliary Control Room to be used in the event Main Control Room (MCR) abandonment is necessary.
This instrumentation is J
required for safe shutdown in the event of MCR abandonment as required by the SQN Appendix R reevaluation.
1.
LI-68-325C Pressurizer Level 2.
LI-68-326C Pressurizer Level 3.
PI-08-336C Pressurizer Pressure 4.
PI-68-337C Pressurizer Pressure 5.
PI-68-3#4; Pressurizer Pressure 6.
TI-68-1C (Loop 1) RCS Hot Leg Temperature 7.
TI-68-24C (Loop 2) RCS Hot Leg Temperature 8.
TI-68-43C (Loop 3) RCS Hot Leg Temperature 9.
TI-68-65C (Loop 4) RCS Hot Les Temperature 10.
PI-1-1C (Loop 1) Steam Generator (S/G) Pressure 11.
PI-1-8C (Loop 2) Steam Generator (S/G) Pressure 12.
PI-1-19C (Loop 3) Steam Generator (S/G) Pressure 13.
PI-1-26C (Loop 4) Steam Generator (S/G) Pressure 14.
LIC-3-164C (Loop 1) S/G Level (and Level Controller) 15.
LIC-3-156C (Loop 2) S/G Level (and Level Controller) 16.
LIC-3-148C (Loop 3) S/G Level (and Level Controller) 17.
LIC-3-171C (Loop 4) S/G Level (and Level Controller) 18.
RI-90-210B Source Range Flux Monitor 19.
LI-62-129C Volume Control Tank Level 20.
LI-68-312C Pressurizer Relief Tank Level 21.
PI-68-311C Pressuriser Relief Tank Level 22.
LI-70-63C Component Cooling System (CCS) Surge Tank Level 23.
LI-70-99C Component Cooling System (CCS) Surge Tank Level 24.
FI-3-163C (Loop 1) Auxiliary Feedwater (AFW) Flow 25.
FI-3-155C (Loop 2) Auxiliary Feedwater (AFW) Flow 26.
FI-3-147C (Loop 3) Auxiliary Feedwater (AFW) Flow 27.
FI-3-170C (Loop 4) Auxiliary Feedwater (AFW) Flow 28.
FI-3-142C Turbine Driven AFW Flow 29.
TI-62-80C Letdown Heat Exchange Outlet Temperature 30.
PI-62-92C Changing Header Pressure 31.
FI-62-93C Changing Header Flow 32.
FI-62-137C Emergency Boration Flow i
-10
. _ _, _ _ _, -.~.
33.
FI-63-173C-R:sidutl Hect R:moval (RHR) R3 turn Flcw 34.
FI-63-91C RHR Pump A-A to RCS 2&3 Cold Legs Flow 35.
FI-63-92C RHR Pump B-B to RCS 1&4 Cold Legs Flow 36.
FI-67-61C ERCW Supply Header A Flow 37.
FI-67-62C ERCW Supply Header B Flow 38.
PI-70-24C CCS Htx A Inlet Pressure 39.
PI-70-17C CC3 Htx B Inlet Pressure g
40.
FI-70-159C Residual Heat Removal Htx A Sup Hde Flow 41.
FI-70-164C Misc Equipment Sup Hde Flow 42.
FI-70-165C Residual Heat Removal Htx B Sup Hde Flow 43.
TI-74-38C Residual Heat Removal Supply (Train A) Dut Temperature 44.
TI-74-40C Residual Heat Removal Supply (Train B) Out Temperature B.2 The following instrumentation is located in the ACR but is not necessary for safe shutdown in the event of MCR abandonment:
1.
PI-30-30C Containment Press Ind 2.
PI-63-120C SIS Accum Tank 1 Pressure 3.
PI-63-102C SIS Accum Tank 2 Pressure 4.
PI-63-83C SIS Accum Tank 3 Pressure 5.
PI-63-59C SIS Accum Tank 4 Pressure B.3 The following controls are located in the ACR in addition to listed instrumentation (A.1) required for safe shutdown:
1.
PIC-1-6C SC 1 Main Stm Hdr Press-Pwr Relf Cntl 2.
PIC-1-13C SG 2 Main Stm Hde Press-Pwr Relf Cnti 3.
PIC-1-24C SG 3 Main Stm Mdr Press-Pwr Relf Cnti 4.
PIC-1-31C SC 4 Main Ste Hdr Press-Pwr Relf Cnti 5.
HS-30-81C CRDM Crd Cool Unit D-B Suct Dmpe 6.
HS-30-82C CRDM Crd Cool Unit D-B Rm Div Dmpe 7.
HS-30-84C CRDM Crd Cool Unit A-A Suct Dmpe 8.
HS-30-85C CRDM Crd Cool Unit A-A Rm Div Dmpe 9.
HS-30-89C CADM Crd Cool Unit C-A Suct Dmpe 10.
HS-30-90C CRDM Crd Cool Unit C-A Rm Div Dmpe 11.
HS-30-93C CRDM Crd Cool Unit B-B Suct Dmpe 12.
HS-30-94C CRDM Crd Cool Unit B-B Rm Div Dmpr 13.
HS-55-L10 Annunciator Power 14.
HIC-62-129C Vol Cont Tank Level Cont 15.
HS-62-74C Regen Ht Exch Letdown Isol Viv C 16.
HS-62-9C RCP 1 Seal Return Flow Cont Viv 17.
HS-62-22C RCP 2 Seal Return Flow cont Vlv 18.
HS-b2-35C RCP 3 Seal Return Flow cont Viv 19.
HS-62-48C RCP 4 Seal Return Flow Cont Viv 20.
HS-62-53C No. 1 Seal Bypass Flow Cont Viv 21.
HS-62-54C Excess Letdown Isol Viv 22.
HS-62-55C Excess Letdown Icol Viv 23.
HIC-62-56C Excess Letdown Flow Cont 24.
HS-52-59C Excess Letdown Div Flow cont 25.
HS-62-69C RCS Inol Viv
~
26.
HS-62-70C RCS Isol Viv 27.
HS-62-72C Regen Ht Exch Letdown Isol Viv 28.
HS-62-73C Regen Ht Exch Letdown Isol Viv 29.
HS-62-77C Letdown Line Isol Viv 30.
HIC-62-78C Letdown Ht Exch Outlet Temp Cont 31.
HS-62-79C Letdown Flow Temp Diversion Cont Vlv 32.
HIC-62-81C Letdown Ht Exch Press Cont 33.
HIC-62-83C RHR Letdown Flow Cont 34.
HS-62-84C Charging Flow to RCS Spray 35.
HS-62-85C Charging Flow RCS CL Loop 1 36.
HS-62-86C Charging Flow RCS CL Loop 4 37.
HIC-62-89C Charging Flow Cont Viv 38.
HIC-62-93C Charging Header Indicator Control 39.
HS-62-118C Diversion Flow to Holdup Tanks 40.
HS-63-24C SIS Accum Fill Line Isol Viv 41.
HS-63-38C Boric Acid Trf Pmp to Boron Inj Tank 42.
HS-63-41C SIS Boron Inj Tank to CVCS BA Tank 43.
HS-63-42C SIS Boron Inj Tank to CVCS BA Tank 44.
HS-63-63C SIS Accum Tank 4 N2 Hakeup Viv 45.
HS-63-64C SIS Accum Tank N2 Hdr Inlet Vlv 46.
HIC-63-65C SIS Accum Tank N2 Hde Inlet Viv Controller 47.
HS-63-66C SIS Accum Tank 4 Drain Viv 48.
HS-63-70C SIS Accum Tank 4 Fill Vlv 49.
HS-63-77C SIS Accum Tank 3 Fill Vlv 50.
HS-63-87C SIS Accum Tank 3 N2 Hakeup Viv 51.
HS-53-90C SIS Accum Tank 3 Flow Isol Viv 52.
HS-63-95C SIS Accum Tank 2 Fill Vlv 53.
HS-63-107C SIS Accum Tank 2 Flow Isol Viv 54.
HS-63-110C SIS Accum Tank 2 Flow Isol Vlv 55.
HS-63-115C SIS Accum Tank 1 Fill Vlv 56.
HS-63-127C SIS Accum Tank 1 N2 Hakeup Viv 57.
HS-63-130C SIS Accum Tank 1 Drain Vlv 58.
HS-63-71C SIS Check Viv Leak Test Isol 59.
HS-67-84C Lower Cntmt Vent Clr A Supply Control Vlv 60.
HS-67-85C Cnti Rod Drive Vent Clr A Sup Cnti Viv 61.
HS-67-92C Lower Cntmt Vent C Supply Control Viv 62.
HS-67-93C Contcol Rod Drive Vent C Clr C Sup Cnti Viv 63.
HS-67-100C Lwr Cntmt Ven Clr B Supply Control Viv 64.
HS-67-101C Control Rod Drive Vent Clr B Sup Cntl Viv 65.
HS-67-108C Lwr Cntmt Vent Clr D Supply Control Vlv 66.
HS-67-109C Control Rod Drive Vent Clr D Sup Cntl Viv 67.
HS-68-301C RCS Pressurizer Relief Tank 68.
HS-68-303C RCS Flow Cntl Viv Primary Mater to PRT 69.
HS-68-305C RCS Flow Cntl Viv Wds N2 Han to PRT 70.
HS-68-307C RCS Flow Cntl Vlv Wds Ca to PRT 71.
HS-68-308C RCS Flow Cntl Vlv Wds Ga to PRT 72.
HS-68-310C RCS Flow Cntl Vlv Pet to WDS RCDT 73.
HS-68-334C RCS Pressurizer Pressure 74.
HS-68-340AC RCS Pressurizer Pressure 75.
HS-70-63C Surg Tank Demin W Inlet Viv 76.
HS-70-66C CCS Surge Tank Vent Viv 77.
HS-70-85C Excess Letdcwn Htx Outlet Viv
-12_
78.
HIC-74-16C RHR Ht Ex A outist Flow C:nt Viv 79.
HIC-74-28C RHR Ht Ex B Out Flow Cntl Vlv 80.
HIC-74-32C RHR Ht Exch 1 and 2 Bps Flow Cnti Viv 81.
HS-77-9C Reactor Coolant Dr Tank Flow Control 82.
HS-77-16C Reactor Coolant Dr Tank To Gas Analyzer 83.
HS-77-18C Reactor Coolant Dr Tank to Vent Header 84.
HS-77-127C Reactor Bldg Sump Discharge 85.
HS-81-12C PW RCS Press Relief Tk and RCP Standpipes 86.
HS-90-21D Backup Source Range Channel-Det Voltage B.4 The following instrumentation and controls are available in the ACR for controlling and monitoring the Emergency Diesel Generators:
1.
HS-55-L4A Annunciator Power Panel A & C 2.
HS-55-L4B Annunciator Power Panel B & D 3.
1-EI-57-29C 480V SD BD 1Al-A 4.
2-EI-57-29C 480V SD BD 2Al-A 5.
1-EI-57-30C 480V SD BD 1A2-A 6.
2-EI-57-30C 480V SD BD 2A2-A 7.
1-EI-57-40C 6.9 kV BD 11A SD BD 1A-A 8.
2-EI-57-40C 6.9 kV BD 2A SD BD 2A-A 9.
1-EI-57-65C 6.9 kV BD 1D SD BD 1-B-B 10.
2-EI-57-65C 6.9 kV BD 2D SD BD 2B-B 11.
1-EI-57-67C 6.9 kV BD 1C SD BD 1B-B 12.
2-EI-57-67C 6.9 kV BD 2C SD BD 2B-B 13.
1-EI-57-83C 480 V SD DD 1D1-B 14.
2-EI-57-83C 480 V SD BD 2B1-B 15.
1-EI-57-84C 480 V SD BD IB2-B 16.
2-IE-57-84C 480 V SD BD 2B2-B 17.
1-EI-57-38C 6.9 kV BD IB SD BD 1A-A 18.
2-EI-57-38C 6.9 kV BD 2B SD BD 2A-A 19.
EI-82-6C 6.9 kV BD Voltmeter Generator IA-A 20.
IS-82-6C 6.9 kV Shutdown BD 1A-A Voltmeter Selector 21.
EI-82-9C Diesel Generator 1A-A to Shutdown BD 1A Amps 22.
EI-82-10C Diesel Generator 1A-A Watts 23.
EI-82-11C Diesel Generator 1A-A Volt-Amps 24.
HS-82-16C Diesel Generator 1A-A Emergency Start SW 25.
HS-82-17C Diesel Generator 1A-A Emergency Stop SW 26.
EI-82-36C 6.9 kV BD Voltmeter Generator 1B-B 27.
XS-82-36C 6.9 kV Shutdown BD IB-B Voltmeter Selector 28.
EI-82-39C Diesel Generator IB-B to Shutdown BD 1B Amps 29.
EI-82-40C Diesel Generator IB-B Watts 30.
EI-82-41C Diesel Generator 1B-B Volt Amps 31.
HS-82-46C Diesel Generator IB-B Emergency Start SW 32.
HS-82-47C Diesel Generator 1B-B Emergency Stop SW 33.
EI-82-66C 6.9 kV BD Voltmeter Generator 2A-A 34.
IS-82-66C 6.9 kV Shutdown BD 2A-A Voltmeter Selector 35.
EI-82-69C Diesel Generator 2A-A to Shutdown BD 2A Amps 36.
EI-82-70C Diesel Generator 2A-A Watts 37.
EI-82-71C Diesel Generator 2A-A Volt-Amps 38.
hS-82-76C Diesel Generator 2A-A Emergency Start SW 39.
HS-82-77C Diesel Generator 2A-A Emergency Stop SW 40.
EI-82-96C 6.9 kV Shutdown BD Voltmeter Generator 2B-B 41.
XS-82-96C 6.9 kV Shutdown BD 2B-B Voltmeter Selector 42.
EI-82-99C Diesel Generator 2B-B to Shutdown BD 2B Amps 43.
EI-82-100C Diesel Generator 2B-B Watts 44.
EI-82-101C Diesel Generator 2B-B Volt Amps 45.
HS-82-106C Diesel Generator 2B-B Emergency Start SW 46.
HS-82-107C Diesel Generator 2B-B Emergency Stop SW Controls for the following 6.9 kV components are located just outside the ACR in the 6.9 kV shutdown board rooms (per unit):
1.
ERCW pumps (4) 2.
Motor-driven AFW pumps (2) 3.
RHR pumps (2) 4.
Centrifugal charging pumps (2) 5.
Pressurizer heaters (4 groups)
The following controls are located adjacent to the 6.9 kV shutdown board rooms in the 480 V shutdown board rooms (per unit):
1.
CRDM cooler fans (4) 2.
Lower reactor compartment cooler fans (4) 3.
CCS pumps (5 per plant) 4.
Fire pumps (4 per plant) 5.
Shutdown board room chillers (2 per plant)
Additionally, controls are located one elevation above the ACR in the 480 V MOV board rooms for all valves powered from these boards required for saf9 shutdown.
C. The above instrumentation and controls are well in excess of that detailed in IE Information Notice 84-09.
There are also numerous local indications and controls available to the operators outside the ACR which provido additional information and control which were not included in the above listing.
D. Th3 instrumentsticn diccucaed in prrt B is Evsilable to the operator in a central location and completely separate from the corresponding instrumentation located in the MCR.
Operators are periodically trained in shutdown procedures from the ACR.
The instrumentation and controls are fully adequate and sufficiently similar to that available in the MCR to permit a safe, orderly shutdown if necessary. SQN startup testing has adequately demonstrated the ability to safely shutdown during the units from the ACR.
IV.
Adequacy of Indications for Natural Circulation The following indications are available to the operator in the ACR to indicate loss of natural circulation cooling:
1.
Reactor Coolant System (RCS) Subcooling (Conversion of pressurizer pressure to saturation temperature and subtracting T 2.
T stable or decreasing.
hot 3.
Steam Generator pressure stable or decreasing.
All of the above indications are ;;acified for use in SQN's Emergency Operating Instructions, specifically ES-0.3, to verify adequate natural circulation. _.
Tha Westingh:ura owntra' Crcup (WOG) Emergsney Rzepcnss Culdslints (ERGB),
i Revision 1, Generic Issue on Natural Circulation offers specific guidelines on operator verification of natural circulation. The primary means recommended by this section for verifying natural circulation are:
1.
Verification of RCS subcooling 2.
Wide Range T 3.
S/G Pressure The natural circulation section further states that " Cold leg temperature (T ) readings can be used as additional verification that heat removal through the steam generators is occurring." It should be noted that T
is an additional verification of natural circulation cooling not old the preferred or primary means.
WOG ERGS also state " Actual tests have shown that loop T
's f 11 w alm st exactly (in trends) the steam CL generator pressure variations, with minimal time lag."
NRC issued a Safety Evaluation Report (SER) of the WOG ERG's on June 3, 1983 stating, "We have concluded that the guidelines are acceptable for implementation and will provide improved guidance for emergency operating procedure development." A supplemental SER was issued by NRC on December 26, 1985 for Revision 1 of WOG ERGS, and closing out open items from Rev. 0 (natural circulation was not an open item).
V.
Cost of Teoid Modification A.
TVA has evaluated the cost to install T instrumentation in the ACR.
Such an installation will be neither easy nor inexpensive to accomplish.
It will require that the Reactor Coolant System (RCS) be penetrated four times to install four new thermocouple wells.
The selection of this modification was to maintain consistency with our original design concept.
The concept provided hot and cold leg RTDs to the MCR and independent hot leg thermocouples to the ACR.
If cold _
Icg inatrumentcticn is to bs Edded it would also bs a th rmoccuple output to the ACR. Approximately 3200 feet of cable will be required and its installation will require the opening and reclosing of a number of rated penetrations including penetrations into containment. Power supplies, ACR instrumentation, and associated electrical equipment will be required.
The majority of the work will have to be accomplished in congested areas, and in the case of the thermowell and thermocouple installation, in areas of high radiation.
i-l' The folowing man-hour estimates have been prepared for the proposed 4
work:
Carpenter 944 Asbestos worker 482 Electrician 5668 Steamfitter
-782 Laborer 626 Inst. Maint.
64 Quality Control 448 l
Operations 16 Subtotal 9030 l
l.
.m-
Fiold Engin 4 ring Mechanical 120 Electrical 240 Total for Installation 9390 man-hours Design 3125 Total 12,515 man-hours (Per unit)
The estimated cost breakdown to install T for a single unit is:
Design
$150,000 Installation 448,180
$598,180 per unit B.
In addition to the design and installation cost there is considerable radiation exposure associated with this work.
The following is the estimate of the exposure anticipated on a per-unit basis.
Primary loop piping work 172.5 man-rem General containment work 95.25 man-rem Annulus 0.65 man-rem 268.4 man-rems The estimate cost of this exposure is $1,342,000 based on a standard cost of $5,000 per man-rem of exposure.
f i
As a summary the installation of T on both units at SQN will cost an estimated $3.9 million and results in a radiation exposure of 536.8 man-rems.,
THIS EXPOSURE WOULD INCREASE ANNUAL WHOLE BODY EXPOSURE FOR SQ2 BY 50 PERCENT IN THE YEAR INSTALLATION OCCURS.
The above estimates do not include the cost of a post-modification hydrostatic test of the RCS, the cost of long-term maintenance, nor the cost of lost generation if this project is a critical path activity for a refueling outage.
C.
As one alternative to the installation of a separate T eold instrumentation, TVA evaluated the use of the existing MCR loop to feed the ACR.
The MCR T instrument consists of a RTD from each cold leg.
Cables from the RTDs go to the auxiliary instrument room located in the control building. At that point the resistance input from the RTD is converted to a current output which drives a number of T d
output devices in the MCR and computer room.
If the output to the ACR was added, with the power supply and resistance / current convertor located in the auxiliary instrument room in the control building and with outputs to other rooms, the ACR output could be lost if a fire occurred in the any of the major areas of the control building.
This would violate the Appendix R separation criteria specified in Section III.L.
Therefore, this option is not acceptable..
A ccc:nd cpticn was syslur,tsd th t would cchicvs thm d:sirad independence..In order to provide independence between the control building and the ACR it would be necessary to provide a switching system to transfer the resistence loop from the control building to J
the ACR, thus maintaining the separation required by Section III.L of Appendix R.
While providing such a switching system outside the control building to switch the resistance loop to either the control building or the ACR would be consistent with Section III.L of Appendix R criteria it would be technically impossible to achieve.
The introduction of any switch into the resistance circuit would create a condition of variable resistance upon switching. Since the resistance portion of the circuit is extremely sensitive to any variation in circuit resistance it would not be possible to provide an accurato output.
A deviation of 0.4 ohms would produce an error of one degree. This approach would also require two power supplies, one in the control building and a second in the ACR.
The transfer switch would then be switching the resistance output from the RTD between the two power supplies.
Such an arrangement would be difficult to calibrate, and with the variable resistance of the switching function the output would be noncepeatable.
Based upon the technical problems with these options no cost estimates were developed. _
VI.
S/G Pettrur3 Inttrument*ien Adequ*cY to Infer Teol_d.
From the data obtained during startup testing at SQN (ST-9B) and Diablo Canyon (Test Procedure 42.7) the following statistical evaluation was performed concerning the T,,
(obtained from S/G pressure) and T relationship ( T
-T
)*
od sat Sequoyah Diablo Canyon Mean 4.33 F 4.67 F Standard Deviation 3.29 f 1.65 F j
The above temperature differences are well within the tolerance and accursey levels of the instrumentation. The SQN cooldown was terminated at approximately 465 F; however, the Diablo Canyon l
cooldown was continued to below RHR initiation. Since both sets of data were obtained simultaneously (T and S/C pressure), the eold data demonstrates the adequacy of using S/G pressure to determine T,,
and infer Teold' ""
- I"
- E between the two indications. Graphs of both the SQN and Diablo Canyon natural circulation cooldown are included in Section VIII of this submittal.
The natural circulation test at SQN was performed from the main control room and the equipment (not controls) used during the natural circulation tests is identical to the equipment which would be used in an Appendix R shutdown from the ACR.
For example, the auxiliary feedwater pumps, the centrifugal charging pumps, ERCW pumps, CCS pumps are used for natural circulation cooldown from the ACR and were also used during the MCR natural circulation tests.
Therefore, the test results are applicable to a shutdown from the ACR.
l l l
VII.
Summary rnd Conclu'irnn After a thorough review of the issues surrounding the T d
question, TVA's position remains. unchanged.
TVA believes that when taken in total, the facts support the position that T,,
, along with the other plant features, as discussed in this enclosure, will provide for adequate assurance that the plant can achieve and maintain a safe shutdown condition, and that installation of additional T eold TVA's position is based on the following key considerations:
The uniqueness of the SQN ACR design o
The large amount of instrumentation and controls available for o
shutdown from the ACR o
Experience and training in plant shutdown from the ACR Instrumentation provided for verification of natural circulation o
is consistent with WOG ERC's o
Cost of modification inconsistent with benefits o
Installation costs - $3.9 million dollarc o
ALARA Exposure 540 man-rem with a 50 percent increase in station's o
personnel exposure for the year that installation occurs Adequacy of steam generator pressure instrumentation to infer o
cold Increased probability of a small break LOCA as a result of four o
additional penetrations to the RCS.
It lo cpp rint from thic riubmittal that T instrumentation in g
the ACR would result in no determinable increase in the public health and safety. The indepeth review performed has demonstrated the adequacy of the existing design. Therefore, we believe that a deviation is justified to the NRC guidance contained in OIE Information Notice 84-09.
a.
9 O
SECTION VIII SEQUOYAH/DIABLO CANYON NATURAL CIRCULATION GRAPHS
SEQUOYAH NATURAL CIRC COOLDOWN 600 a
590 -
580 -
C 00
_g 570 -
560 -
550 -
C Q T M ~j ?-? ?,h^ri ? i 540 -
v y
530 -
a Q
520 -
cc LU 510 -
CL 3
500 -
i--
490 -
480 -
470 -
460 -
A..
450 -
440 m
i O
100 200 300 400 TIME, MINUTES D
- 1Th
+
- 1Tc o
- 1Tsat A
RCP's Tripped
SEQUOYAH XATURAL CIRC COOLDOWX
- 2 STEAM GENERATOR 590 -
580 -
570 -
- ~ - %C ~
[~~_m
~
~
560 -
550 C
0 0
" - -- O o-c 0
0 0 0 0
^
540 -fHk v
530 -
a Q
520 -
ew 510 -
O_
3 500 -
s 490 -
480 -
470 -
460 -
450 -
440 o
O 100 200 300 400 TIME, MINUTES D
- 2Th
+
- 2Tc o
- 2Tsat A
RCP's Tripped
SEQUOYAH NATURAL CIRC COOLDOWN
- 3 STEAM GENERATOR 590 -
_y3-=-
~~~
580 -
570 -
560 -
550=
+_;
F H-o-o--o-o-+-o--o-o-o-%
1 540_
v 530 -
3 Q
520 -
xw 510 -
n.
3 500 -
s 490 -
480 -
470 -
460 -
450 -
. e 3 440 m
i O
100 200 300 400 TIME, MINUTES D
- 3Th
+
- 3Tc o
- 3Trat A
RCP's Tripped
SEQUOYAH XATURAL CIRC COOLDOWN
- 4 STEAM GENERATOR 590 -
m m
S-;
~
=
580 -
~~~
570 -
560 -
550 4H 1
540 I
I$
+-
^
m 530 -
D Q
520 -
xw 510 -
a.
3 500 -
H 490 -
480 -
470 -
460 -
\\
^
o 450 -
440 m
O 100 200 300 400 TIME, MINUTES a
- 4Th
+
- 4Tc o
- 4Tsot A
RCP's Tripped
DIABLO CANYOX STEAM GENERATOR NATURAL CIRC COOLDOWN 650 600 -
0 g
t1 0 550 -.,
pggggg
- +,0 0
0 000
- +00 oo 0
500 -
+%hu mb O
+*Da 450 -
3 Q
- %.g a Ou
- $u Fo 400 -
o_
8o o 2
N
$guu 350 -
o 1.,.Do$y8 ou
- 8 8*$+999 300 -
0
+ +Bo 250 -
t1
+
+
200
....i....
....i....
O 2.5 5
7.5 10 12.5 15 17.5 20 22.5 25 TIME, HOURS D
- 1Th
+
- 1Tc o
- 1Tsat
DIABLO CANYON STEAM GENERATOR NATURAL CIRC COOLDOWN 600 C
g uD 550 -
gggggg U
- t,+Duun O
ao o,
++++%
a D
500 -
g*aa C
$$a 450 -
a v
- 8 0 W
8+ a D
Q 400 -
O +DD
- +
e o
o 0
+D 2
350 -
O*D U
0+D a
U U
0++,o++++U D
0 a a
D o
o 300 -
o o +4 n
o D
08+* S
!3 250 -
oo
+
200
....i....
O 2.5 5
7.5 10 12.5 15 17.5 20 22.5 25 TIME, HOURS D
- 2Th
+
- 2Tc o
- 2 Teat
eu d
+
l
+
i 9
+
. 5 1
9
+
. 2
+
a
+
a
. 5 a" $
. 2 8
. 2 N
D$.
W Dg O
u+
. 0 t
D c%
i 2 a
L o4 s
O D +o T
O 0 +*
3 NC a8
. 5
. 7 OC g
8
. 1 R
ng o
YC I
U
- aA NL o4
. 5 SR A
D#
U 1
AR a+
O U
CT D+
H A
U,
. 5 c
,T N
o*
. 2 E3 O
U*
. 1 M#
R at I
LO D#
T T
0+
BA a+
0
+
R 0+
. 1 AE 0*
IN 0*
E DG 0*
. 5 U,
i M
+
. 7 a+
h A
E g
T3 T
g S
g i 5 g
g O
a o
o i 5 a
. 2
,0 D
0 n.
O 0
0 0
0 0
0 0
0 0
0 0
5 0
5 0
5 0
5 0
5 0
5 6
6 5
5 4
4 3
3 2
2 1
C[eaQe1b'-
i
DIABLO CANYOX STEAM GENERATOR NATURAL CIRC COOLDOWN 650 3
O 600 -
a t1 0 550 -.,,
,99999a o
- t *c***+aa oco o oo u
500 -
+g$U a
C 8UD 450 -
u
- g%g o w
u 8u Q
400 -
g Fu 88 a
2
$*+0 1
350 -
o go
+
o o a
88
+U 300 -
,a o+999 4no "s i
250 -
++
0
+
13
+
200 -
+
150 O
2.5 5
7.5 10 12.5 15 17.5 20 22.5 25 TIME, HOURS a
- 4Th
+
- 4Tc o
- 4Tsat 4