ML20008G250
| ML20008G250 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/01/1981 |
| From: | Wisenburg M TENNESSEE VALLEY AUTHORITY |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, RTR-REGGD-01.097, RTR-REGGD-1.097, TASK-2.F.2, TASK-TM NUDOCS 8107070147 | |
| Download: ML20008G250 (21) | |
Text
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L. -
TENNESSEE VALLEY AUTHORITY CH ATTANOOGA TENNESSEE 374ot 400 Chestnut Street Tower II
. July 1, 1981 Dircctor of Nuclear Reactor Regulation Attention: Ms. E. Adensam, Chief Licensing Branch No. 4 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Ms. Adensam:
'In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 In accordance with the requirements of the Sequoyah Nuclear Plant units 1 and 2 operating licenses, we are enclosing our tentative schedule for compliance with Regulatory Guide 1.97. Additionally, the enclosure provides information on the incore thermocouples as required by
'NUREG-0737 item II.F.2. We expect to provide a definitive iist of post accident monitoring parameters with an accompanying design criteria by November 1, 1981.
If you have any questions, please get in touch with D. L. Lambert at FTS 857-2581.
Very truly yours, TENNESSEE VALLEY AUTHORITY 1
M. R. Hisenburg Nuclear Enginee,'
, Sworn and subs b before me th ~ day o ~1981
'NotagPublic
~
j jU Ny C5mmission Expires M/M/ h Enclosure
' 8107070147 8107 7' i
PDR ADOCK 05000 An Equal Opportunity Employer
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- ENCLOSURE
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Regulatory Guide-1.97' Response g 'Sequoyah' Nuclear Plant Units 1 and 2
,y -
4
- Scheduling Comments Thefpreliminary tasks associated with TVA's' Regulatory Guide 1 97, Revision. 2, ' program have been . completed; -ir. depth evaluations are continuing. TVA has
- found only a. few PWR variables for which we will seek cexceptions to the provision and schedule of the guide. However, TVA fully.
1 expects :to meet .the intent of Regulatory Guide 1.97, Revision 2.
TVA anticipates delays'in procuring'the inst"umentation needed for
="-
category 1 items. 'Primarily, these delays' are due to the fact that; qualification testing has not'been completed on the. type instrumentation
~
' _needed. TVA has divided the PAM instrumentation into two groups (defined 4
below)i Implementation;for group-I will proceed on a systematic and
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. preplanned sch'edule based on the design, procurement, and outage schedule.
' A .moref definitive scheduleLcannot be supplied at this stage of the program
~
.due1to the. variables discussed herein. Group IILcannot be implemented
^3;* "
~'byJJune11963 due to (1) nonavailability of instruments-(regulatory
~
- requiremer ss are beyond th'e state-of-the-art), (2)- procurement delays, Cand
- (3) sualification'and testing delays. Our:best-estimate at this time
' for the. design _ duration:for groups I.and II is approximately 18 and-rt J30 months, respectively., .
- We' estimated :it will' be at least the ~ end of the year before category- 1 type transmitters are available..'Because many purchasers will be flooding the
- market place' to procure such instrumentation, we anticipate additional
-delays:in getting equipment delivered. We have estimated this to be one year. x For most' radiation monitors, we estimate it will take at.least 24 morths to receive : delivery. - ,
Some ' instruments,t t,uc'h. as thi neutron flux detectors, . reactor coolant
. system radiation monitors, and main steam line radiation monitors require l- . . additional development. . Because of this, it is difficult to estimate
- - procurement' durations for these items. After-the development phase is i-Ecompleted, we' estimate the testing
- and actual procurement duration will be
[
i similar to the radiation monitors mentioned previously.
'In some : cases, 'it will-be necessary to interface with the NSSS contractor's 4 equipment. 1This interface will'be performed in conjunction with TVA's
! _; . design. phase. -
Aslwe have described, the1 availability.of many instruments will be
- delayed. LEven thoughtsome vendors are making promises of fully qualified 0
Linstruments to be:available soon,:our experience has'shown that they are s- .
? -
A 4 + r 7~
,.ly ' , , - -
4
not always able to keep such promises. H.aever, just because the instruments are not presently available, we do not believe the associated functions should be ignored. Rather, a longer lead time before implementation will be required for those functions which TVA determines will significantly increase the safety margin of their plants.
Other instruments, such as radioactivity in the circulating reactor coolant b
. monitor, do not exist commercially at this time. For instruments in this
- category, i.e., group II, TVA will make every effort to use an alternate
-means of meeting the ir.t;nt of the regulatory guide. For example, the sampling system will be used in lieu of a reactor coolant system monitor as an interim measure. There are those in the industry who believe the sampling system could provide more specific and unambiguous indientions of the problem by identifying isotopes and concentrations and eliminate the crud burst or iodine . spike 'as a source of confusion to the operator. The containment high-range area monitors will already be measuring the radiation level in the containment.
Nevertheless,-TVA will encourage and participate in to the degree practicable the development of this instrument and others, evaluate those which appear promising, and determine if the aforementioned safety margin would be increased by cheir use.
The best estimate at this time of the group II instruments is as follows.
- 1. Most radiation monitors
- 2. -Incore thermocoUples (possibly) 3 Neutron flux (possibly)
- 4. . Loops requ' iring qualified trans'mitters (possibly)
The remainder of the variables will be group I types barring unforeseen difficulties.
Coalescing Post TMI-II NUREG's The regulatory documents that primarily interrelate with Regulatory Guide 1.97 are NUREG-0737, NUREG-0700 (not issued), NUREG-0696, NUREG-0654, Regulatory Guide 1.23, and NUREG-0588. All of these are in different phases of planning and implementation. In our review of these documents, we believe the mos significant inter- .ationship is with the main control room human factor NUREG's. These requirements have been developed by NRC in order to help ensure that human factors are considered throughout the control ro'om. Included in the requirements is a detailed human factors review of the control room expected to proceed over a year's duration. At this time, we are in the process of forming human factor review committees c to do the reviews. In addition, they will also review all changes, additions, etc., planned by other requirements, such as PAM. As these reviews progress, problems may be uncovered which could impact the PAM
%/
c~ _ _ _ _ _ - - - - - - _ _
schedule, i.e.,
such as the space problem on the MCR panels mentioned For example, there are two general concerns thac TVA has not been below. These are potential space problems able to fully assess at this time. associatedThis withwill the main take a more control panelsW-an instrumentatfon that must be added to these areas.
detailed study to determine and is in progress now.
TVA will provide a definitive list of PAM varidbles 1981.
with nn accompanying design criteria to the Co= mission on November 1, Sequoyah Postaccident Monitoring (PAM) Variables of D1 TVA initiated a PAM instrument review in mid-1980, i
Py in the TVA nuclear program review. from first principles.
bles and apparent, the variables in Table 1 (attached) were derived There are some noticeable differences between the regulatory control rod position is listed in the regulatory gu ide guide as varia .
TVA variables, i.e., 3. Differences l a type B, category 3; TVA has this variable as a type D, category d by TVA in l such as the one mentioned above are a result of the methodology TVA u selecting the variables. Explanatory comments are included with the tabic. ll and TVA'in a few cases. be believes cases.
it is meeting ' the intent of Regulatory design and Guide required to meet the intent of the regulatory guide regarding
. qualification criteria. bject to Thedatainhable1isaresultofTVA'spreliminaryreviewsandissu change as the program progresses.
Program Schedule Sequoyah's i
The attached figure 1 indicates TVA is in the final phase of evaluat ngThe d PAM instruments and TMI-II requirements. tentative at this point in the program.
procurement phases are obviously very 'tedule will evolve. TVA's definition of As the program progresses, a firmer qualification categories will be submitted with the design eziteria.
E
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TABLE 1
- (
.B SNP PAM VARIABLES l.i- t s,
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R.G.-1.97, R2 TVA PARAMETER TYPE ' CAT. - RANGE TYPE CAT. RANGE- -
-COMMENTS" l
- Neutron flux . B .1 10-6% to A,B 1
-Sourgerange . Upgrading may be required.
100% full 1-10 CPS .
j power ,
l'-
1 B .1- Inter. range 10 '
10-3 amps I ;
l! .Contr$1l rod:. .B 3 Full in or .
.D 3 Full in or Individual control rod bottom lights, position not full in not full in No' upgrading required.
~ !. .
I
'I RCS soluble boron B 3 0-6,000 ppm D '3' 0-5,000 ppm See note 1.
f- concentration i- ,
RCS cold leg B 3 1500F-4000F !! A,B, 1 0-7000F Teold; See notes 2 and 3 I
water temperature B 1 50 F-7500F D Recorder upgrading may be. required.
4 y
+
- l- .
!- I .l;- '
1
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I
i 4
R.G. 1.97, R2 TVA PARAMETER TYPE CAT. RANGE TYPE CAT. RANGE- COMMENTS
- l RCS hot leg water- .B 1 500F-7500F A,B, 1 0-7000F T hot; see note 3 Recorder-temperature ,D upgrading may be required.
i RCS pressure B,C 1 0-3,000 psig A,B, -1 0-3,000 psig some upgrading may be required.
l C l
l Core exit temper- 3 3 200-1,6500F B,C * 'See appendix A.
ature- C 1
. (-
Coolant level in B 1 Bottom of core B * - 'This system will meet the eniteria reactor to top of outlined in TVA's response to II.F.2
- vessel of NUREG-0737.
1 l
l Steam generator A 1 1.5 x 10 Some upgrading may be required.
blowdown radi- p.ci/cc to TVA is presently evaluating alternatives ation 2.4 x 10-2 for this function. The main steam Aci/cc radiation monitor may be deyeloped,
! or this parameter and the cdndenser air ejector monitor may be upgraded.
Degrees of sub- B 2 2000F Sub- A,D 8 2000F Sub- "This system will meet the criteria cooling cooling to cooling to in TVA's response to NUREG-0737 II.F.2 350 F super- 35 F super- and NUREG-0578 2.1.3(b).
l heat i aeat l
Containment sump B,C 2 Narrow range .D 3 Narrow range level B,C 1 0-600,000 gal._;A 8 0-20 feet 'This system will meet the criteria outlined in TVA's response to NUREG-0737 II.F.1, Atth. 5 and NUREG-0578 2.1.9(c).
l 4
e
i H.G. 1.97, R2 TVA I. PARAMETER TYPE CAT. RANGE TYPE CAT.
~
RANGE COMMENTS' 3
{ ' Containment B 1 0-design. A,B, 1 -1 to +15 psig Some upgrading may be required.
~ pressure pressure (psig).C B,C 1 10 psia
- design pressure -
t
-C 1 10 paia - 4 C *
-5 to + 60 psig 'This system will mee't the criteria times design outlined in TVA's response to NUREG-0737 pressure II.F.1, Atth. 4 and NUREG-0578 2.1 9(a).
Containment C 1 Closed-not B 1 Closed-not TVA may request exception in certain isolation' valves closed closed areas of the category 1 on some
' position indicator isolation valves.
Radioactivity C 1 1/2 tech spec C 1 0.01-100% TID See note 6. Since an instrument for concentration limit to 100 this function is not presently or radiation level times tech spec available, TVA is not committing to in circulating limit this' requirement. As instruments become
, , primary coolant. available, TVA will el valuate them on a case-by-case basis and determine from those. evaluations if the retrofit would be justified. The post-accident ~
sampling system (see below) will be used i
! to meet the intent of the R.G. for this pacameter. See scheduling comments.
Analysis of C 3 10saci/gm to E 3 This parameter will be covered by the l primary coolant 10 ci/gm or postaccident sampling system.
l (gamma spectrum) TID source term in coolant Containment area C 3 1 R/HR to 104 A,C, *
'This system will meet the criteria radiation R/HR D,E outlined in TVA's response to NUREG-0737 II.F.1, Atth. 3 and NUREG-0578 2.1.8(b).
R/HR R
- s. ,
I hlI-
'R >
a.
,h .11 -
r l [F ' R.G. 1.97, R2_ TVA .
j' . PARAMETER TYPE CAT. RANGE i TYPE CAT. RANGE COMMENTS Q:-
Effluent radio- C 3 10-6 # ci/cc A,C,E 1 2 3 x 10-7 Since this instrument, cond. air ejector I
l activity - Noble to 10-2 j4eifee to 105 w ei/cc radiation monitor, is-in the turbine
, ' gas effluent in' (xe-133) building which is not a seismic s condenser air structure, upgrading will be to the l removal system extent practicable under that condition.
l4
! Wi exhaust- See comment on main stcam line monitor below.
l 1
[ Containment H 2 C 1 0-30% A,B,C
- O -10% See note 21.
l i concentration *This system will meet the criteria outlined in TVA's resp,,nse o to NUREG-0737
.]h
.y II.F.1, Atth. 6 and NUREG-578 2.1.'9(b).
?
!d Containment C 2 10-6 to C,E *
- Radiation monitor on shield building effluent radio- 10-2 /4. ci/cc vent (gaseous). This system will meet
' j!j -
, activity - Noble' the criteria outlined in TVA's r esponse j gases from to NUREG-0737 II.F.1, Atth. 1 anc!
identified release NUREG-0578 2.1.8(b).
]'s points
- 1
! Radiation C 2 10-1 to None See note 8. s
'j exposure rate 104 R/HR ' p
-}.
j Radiation C 1 , A,C 1 Must be Since an instrument is not available now monitor on main determined to perform this function, TVA is not steam line committing to this variable.. As H instruments become available, TVA will 9
evaluate each and determine if J installation is justified. This i i: parameter could be used as an alternate j , to condenser air ejector radiation and
'] '
'G blowdown radiation.
J i 4 "I High head A 1 Running-not No upgrading required. -
l injection pump ! running g running i
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- R.G. 1.97, R2 -TVA
' PARAMETER TYPE CAT.
RANGE TYPE CAT. RANGE COMMENTS 4
RHR ' system flow - D- 2 0-110% D
~
' design flow .
3 0-100% No upgrading required.
~
~ N RHR heat. exchanger D- 2 300F to D.
3 500F to The inlet temperature will be used~to
' inlet and outlet 350 F '4000F to monitor the~ sump temperature temperature
- when-suct!on is taken from there. No
.-Accumulator tank- upgrading required.
- Level D 2 10% to 90% D 3 Top 20 inches See note 9. No upgrading required.
-volume Pressure- D. 2 0-750 psig D' 3 0-110% See note 9 No upgrading required.
,' .. Accumulator. D 2 Closed or open D Open/ closed isolation valve 3 No upgrading required.
position I
!' Boron injection f
D 2 0-110% design D 3 0-100% No upgrading required.
flow: flow Flow in HPI D 2 0-110% design D syscem 3 0-100%- Centrifugal charge pump flow. No flow upgrading required.
,D 3 0-1005- Safety injection pump flow. No upgrading required.
Refueling water D 2 Top to bottom :A,D
. storage tank level 1 0-1005 Upgrading may be required.
~
Reactor.ncoolant' D 3 Motor current D 3 0-110% current No upgrading required.
l pump status ._ ._ _ _ _ _ _
( w 4 )
l- ,
(
! 4 L
R.G. 1.97, R2 TVA .
PARAMETER- TYPE CAT. RANGE TYPE CAT. RANGE COMMENTS
-Primary system cafety relief valves PRZR PORV D 2' Closed-not D 3 Open-closed- Will use status lights on MCR closed handswitches. No upgrading required.
PRZR Safety Valve D 2 Closed-not D 3- Closed-not Acoustic monitors and red and green closed closed indicating lights. No upgrading required.
t Pressurizer level D 1 Bottom to top A 1 0-100% Upgrading may be required g Pressurizer heater D 2 Electric 'D 3 on/off Status lights on MCR handswitches.
No upgrading required. !
status current Quench tank level, D 3 D 3 See note 10. TVA will use presently temp. &. pressure installed instruments on the pressurizer relief tank. R.G. ranges are excessive due to rupture disc on the tank. No j upgrading required.
Steam generator D 1 Tube sheets A,B,D 1 0-100% Narrow range, see Note 11.sj Upgrading level to separators ! may be required.
D 3 Wide range. No upgrading required.
Main steam ~ D 2 From atmos. to A,B,D 1 0-1200 psig See Note 18. Upgrading may be required.
pressure 20% above! (SG presure) l'owest safety valve setting
. Emergency boration D 3 0-150 gpm No upgrading required.
flow Steam generator D 2 Closed-not .D 3 0-110% Main steam flow. No upgrading required.
. safety / relief valve closed design flow positions or main steam flow A
I L ,
R.G. 1.97, R2 TVA ~
PARAMETER TYPE CAT. RANGE TYPE CAT. RANGE COMMENTS L . Main feedwater D 3 0-110% design D 3 0-110% design No upgrading required.
flow Auxiliary feedwater D 2 0-110% design D- 3 0-440 gpm See note 22. This system will meet the flow. flow '
criteria outlined in TVA's response to NUREG-0737 II.E.1.2 and NUREG-0578 2.1.7 (b).
! Crndensate storage D' 1 Plant'specifi. D. 3 Full to See note 13 No upgrading required.
ttnk level empty (0-32 ft)
Containment spray D. 2 0-110% design D 3 0-110% No upgrading require.
flow flow l
H:at removal by D 2 Plant specific None See note 14.
thn containment fan heat removal system Containment atmos. D 2 400F to D- 3 40oF - 4000FUpgrading may be required.,f 0
t:mperature 400 F Containment sum, D 2 500F to See note 15.
.wnter temperature 2500F ERCW to auxiliary D 3 Open/ closed No upgrading required..
feedwater system valve position Makeup flow - in D 2 0-110% design D 3 0-200 gpm TVA will monitor this parameter with flow charging header flow. No upgrading required.
Lstdown flow - out D 2 0-110% design D 3 0-110% No upgrading required.
flow Volume control
- D 2 Top to bottom D 3 Full to empty No upgrading required. .
tank level s
R.G. 1.97, R2 TVA
- PARAMETER TYPE CAT. RANGE TYPE CAT. RANGE COMMENTS Component cooling
~
D 2 '32 F to D 3- 50 F - See note 1. Component cooling water water temperature 2000F 1500F- supply and return temperature. No to ESF system upgrading required.
Component cooling D 2 0-110% design D 0-110% design water flow to ESF 3 See note 16. Component cooling water flow system heat exchanger flow. No upgrading
' required.
High-level radio- D 2 Top to bottom p
D active liquid tank 3 Empty-full Floor drain collector tank level. ,
level
. Upgrading may be required. ,
Radioactive gas D 3 0-150% design D 0-110% design holdup tank 3 See note 17, waste gas decay tanks.
presure Upgrading may be required.
Emergency ventila- D 3 Open-closed open-closed
!D 3 Major dampers. No upgrading required.
tion damper
- position
- j- ~
Status of standby D 2 Voltages, D 3 See comments power and other Voltage and ammeters for all 6900V BDS, currents, voltmeters only for 480V BDS (MCR) (AMP energy sources pressures, important to safety meters on 480 V BDS). No upgrading
! required.
i 0-110% design Diesel wattmeter. No upgrading required.
- Essential air header pressure, diesel
' generator fuel oil day tank level, and starting air pressure are alarmed in the control room to indicate abnormal operation. Local indication is provided for analyzing system problems. No upgrading required.
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~
R.G. 1.97, R2 TVA PARAMETER TYPE CAT. RANGE TYPE CAT. RANGE COMMENTS Upper head D 3 0-110% No upgrading. required.
' injection accumu-lator tank pressure ,
Upper' head D 3 open/ closed No upgrading required.1 injection isolation valve position Upper head- D 3 0-100% No upgrading required.
injection surge installed-tank level range Air return fans '
D 3 Running-not No upgrading required.
~ running running.
Meteorology Wind direction E 3 0-3600, etc. E 3 See note 25.
Wind speed E 3 0-30 mps, etc. E 3 Estimation of E 3 Based on E 3 atmospheric vertical temp.
stability diff., etc.
Accident sampling E 3 See R.G. E 3 NPR IV.A.6'-3&4, TVA ECN 2780 and L5200 capability (Analysis Design criteria is detailed in capability onsite) SQN-DC-V-9.3 Shield building E 2 0-110% E 3 0-110% design Upgrading mr.f be required.
vent flow Shield building E 2 10-6 to E 3 to 102 /* ci/cc Upgrading may be required.
vent monitor 104 jul ci/cc (particulate) ,
R.G. 1.97, R2 TVA .
PARAMETER TYPE CAT. RANGE TYPE CAT. RANGE COMMENTS Shield building 2 Upgrading may be required.
-vent monitor E 3 to10fci/cc (iodine) .
' Radiation exposure To satisfy NUREG-0654 See note 20..
meters (continuous indication at fixed locations).
Airborne radio- E 3 10-9 A ci/cc E 3 10-11 e ci/cc See note 23 .
halogens and- to 10-3 rei/cc to 2 x 10-5 (*-
particulates .
Aa.ci/cc '
(portable !
sampling with onsite analysis capability)
Plant and E 3 10-3 R/HR to ,E 3 * 'TVA's present portable instrumen-environs 104 R/HR, tation will be used. Range details radiation photons will be furnished with Sequoyah's-
'(portable- 10-3 rads /HR final PAM list.
instrumentation) to.104 rads /HR+ ,l BETA tadiation and low energy photons j
Plant and E 3 Multi-channe. !E 3 *- *See note 24.
- environs gamma-ray 1 '-
> activity spectro-meter rtable ;
',trumentation) ! ,
a
, Radiation exposure E 2 10-1 R/HR to l' E 3 * "Sce note 19. ,
2 rate (inside 104 R/HR buildings or areas a where access is :
required to service equipment important ,
u .
hws j, O Comments for Table 1
- 1. .This is a noncategory 1 parameter, and there is no technical basis for increasing the range beyond the range of the presently
-installed instrument.
- 2. The full range is adequately covered by the type A range requirement for Tcold' .
.3 The maximum -temperature the RCS will reach during short transients, including ATWS transients, is-below 7000F. Any temperature above the maximum-expected temperature would be a measure of inadequate core cooling. The core exit TC's are the primary indication for inadequate core cooling and are category 1 instruments.
- 4. Deleted.
- 5. Deleted, e
- 6. One of the TVA purposes of type C variables was to monitor the breach of the fission product boundaries where the event causes the parameters
.to exceed their design basis levels. The range of the primary coolant activity must be high enough to cover these types of conditions.
- 7. Deleted.
l 8' . Discussed in the-comparison of the type E. variables.
- 9. The presently installed level range covers approximately 20 inches at the top of the tank. The tank is approximately 13 feet high. The narrow range is required to obtain the accuracy needed to meet technical specification conditions. The design purpose of the tanks is to inject water into the cold legs during the first few minutes of very large LOCA's. The operator has very little c'ontrol- on reaction time in these conditions. The need or uses of the accumulators beyond the short period is not certain. By using the accumulator tank pressure, the operator can -roughly determine the water level. This would provide the operator with enough information to take any needed action.
- 10. The quench _ tanks collect relatively small discharge from the pressurizer relief valves and safety valves. The tank has a rupture disc which vents the tank to containment if the tank pressure gets too high. This does not prevent the operation of the safety or relief valves.
4
A
- 11. A review of the operating procedures and uses of the SG level information indicates that the operator always requires the level to be in the narrow range. Any time the level falls below the narrow range, the operator will attempt to restore the level unless that particular SG is damaged. The category 1, narrow-range level provides the reliable information the operator needs to take action. The wide-range level instrument provides less reliable information, but there is no big requirement for this information. The combination of ranges sufficiently munitors the SG level.
- 12. Deleted.
13 This indication is not required to be category 1 because the condensate storage tank is automatically backed up by the safety-grade ERCW header supply. The ERCW nas four supplies to the AFW suction.
This indication does not need to be category 1.
- 14. For Sequoyah Nuclear Plant, the containment fan heat removal system is not a safety-grade system. These fans will be isolated by a phase B
- containment isolation signal and will be unavailable to remove heat during accidents when heat removal is a critical function. Also, Sequoyah has an ice condenser system, and no credit is taken for ventilation system cooling during an accident.
- 15. The containment sump temperature is obtained from the RHR heat exchanger inlet temperature.- The containment sump temperature is necessary information during a LOCA when it provides a measure of heat removal from. the circulating water. The RHR heat exchanger inlet
-temperature can provide the required information.
- 16. - The use of the component cooling water heat exchanger flow will include the flow to some non-ESF equipment. This indication will still provide the required information.
- 17. The waste gas decay tanks have relief valves which will prevent the pressure from exceeding the design pressure. There is no reason to have the pressure indicator monitor up to 150 percent of the design pressure.
- 18. The range required by Regulatory Guide 1.97 is 0 to 1,277 psig. This range is slightly above the 0-1,200 psig for the TVA types A and B variables and 0 to 1,194 psig (0 to 110 percent) in the TVA type D variable. The' difference is small, and the lower range can provide the required information.
-e a V
4
- I i
l
- 19. Under type E, the range for fixed radiation-exposure rate monitors j inside buildings or areas where access is required to service ;
equipmentimportanttosafetyisinconsistentwithtgestated function. Most of the specified range of 10-1 to 10 R/hr is above levels considered acceptable, even in accidents, for human entry. The upper' portion of the range is considered lethal.
Knowledge of Lxactly how much higher than what is acceptable for entry is not pertinent to plant personnel. Entry into an area will have already been precluded by the off-scale readings of a reasonable-ranged area monitor. Further measurement, if necessary, can and should be provided by portable monitoring equipment which is already required as a separate item within type E. More specifically, portable monitoring is typically a requirement for any time entry into an area with radiation levels above 100 mR/hr. In addition, the use of portable equipment provides the operator with the flexibility to monitor any suspected high-radiation area. Consequently, it is recommendedthatthegangeforthesepermanentlyinstalledmonitorsbe reduced to 10-1 to 10 mR/hr to be consistent with normal radiation protection practices and that any high range application be handled by portable equipment.
It should also be noted that reducing the range of these monitors and using a few high-range, portable devices when applicable is beneficial in terms of ALARA. Specifically, reducing the range of these fixed monitors reduces the number of in situ, high-range calibrations required annually.
- 20. Sequoyah's specific fixed radiation monitoring system is defined in Section 1.5 and Section 12.3.4 of.the Sequoyah FSAR and
~ Sections 7.1.6.2 and 7.1.6.5 of the Sequoyah radiological emergency plan (REP). Currently installed systems comply fully with all requirements of NUREG-0654, items II.H.5b and II.H.6b. _ _ _ _
- 21. TVA has glow plugs installed in the containment per our licensing
! commitment. Worst-case studieu with the glow plugs in service j indicate the hydrogen concentration will not exceed 8 percent. These I
studies go well beyond the DBA. The glow plugs should be' turned on immediately after identifying the acaldent as a LOCA and not turned j off until the plant is in a stable condition.
i
- 22. The E0I's specify AFW flow og S/G 1evel as the criteria for terminating SI since S/G level is type A, category 1, it can be used.
l
23 Existing, installed airborne radiation monitors at Sequoyah are designed to function in the range of 10-11 f&tCi/cc to 2 x 10-5 ,4.Ci/cc. Emphasis in design of the detectors has been placed on monitoring'small changes in the area radiation to aid the rapid detection of loss in containment systems integrity. Measurement beyond the current 10-# <' 6tCi/cc high range would add little useful information to the detection and identification of losses of containment integrity. Current design therefore meets the intent of e the range specification. ,
24, Each plant health physics laboratory is currently equipped with a single-channel gamma ray spectrometer. In addition, the mobile laboratory facilities sent to the plant' site in an accident are equipped with a mult.tchannel gamma spectrometer. This meets the intent of the requirvment.
- 25. The current meteorological measurement system complies-with Regulatory Guide 1.23,-except for backup temperature indication. TVA is currently reviewing methods for providing backup temperature instrumentation. A detailed description of proposed improvements the the existing meteorological program will be described in response to item III. A.2 of NUREG-0737.
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- Group I R.C.1.97 R2 Review t-I I 1
Identify Program
- Requiremen ts t
' a Evaluate PAM Instruments and l ' TMI-II Requitweents -
t
' 'I Develop Design Criteria (see note 1 and 3) i.
8 Design (see note 2 and 3) i (note 4) t 1
- 1 Procurement (see note 3) i 4
+ - Submit Program Schedule to NRC Notes: Plant Modification 1 - Submit PAM list with Design Criteria to NRC (see scheduling comments) ,
2 - Includes NSSS Vendor Interface Notes (cont'd) ,
3 - This phase is very tentative at this time due to the 4 - submit final implementation schedule to NRC variables discussed in the scheduling comments and the
.p{ g inary stage of the program. -
~F M A N J J A 5 0 N O J F M A N J J A $ 0 3 3 J FM A E J J A 3 3 5 5 J FMA 5 J J A 5 (
1 CROUP II
'l i See note 4
! 33 i Design.Duratiot-s s '
) Approx. 30 mont:
l i
I See note 5 ) .I Procurement Approx. 24 months For Delivery Plant Modification
! Notes (cont'd): .i (see note 6 and
! 4 - Design start time will be determined by Instrument scheduling comments
] Development and Availability 1
5 - Approx. 3 months af ter design start date 6 - Installation for Group 11 can not be forcast at Figure 1 i
this time due to the variables involved. R.G. 1.97 Program
) Schedule for SNP Units 1 and 2
. APPENDIX A <
INCORE THERMOCOUPLES ,
- The following is in response to NUREG-0737, item II.F.2, attechment 1,
" Design and Qualification Criteria for Pressurized - Water Reactor Incore Thermocouples," and NUREG-0578, item 2.1.3(b), same subject. Points are addressed in the'same order and format as followed in attachment 1 of II.F.2:
- l. The Sequoyah incore thermocouples are located at the core exit for each quadrant, and in conjunction with core inlet RTD data, are sufficient to provide indication of radial distribution of the coolant enthalpy rise across representative sections of the core.
Sixteen (four per quadrant) of-the core-exit'thermocouples will be designated as PAM sensors.
- 2. The primary-operator display is a computer-driven printer. This
-system has the following capabilities:
- a. A spatially oriented core map is available on' demand which indicates the temperature at each core exit thermocouple
. location.
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- b. An example of the Sequoyah selective readings is an on-demand tabular listing of all instantaneous incore thermocouple values,
- c. A printout'of average, instantaneous and maximum values is provided for all T/C temperatures. 'The range will meet the suggested range in the RG (200 F to 2300 F).
- d. Trend capability showing temperature time histories is designed into the system. ~ Strip chart recorder points are availabic
_to assign.to any incore thermocouple on demand. In addition, a point value trend printout is available on the control room printer,
- e. Alarm capability is provided in conjunction with the subcooling monitor which uses the average of all the T/C readings in tha calculations,
- f. The control room displays are designed for rapid operator access and ease of viewing data. Also, the incore program has a validty-check comparison which reduces the probability of accessing false readings.
. 3. A-backup analog readout is provided with the capability of selective reading of any T/C in the system. The range of the system is 0-700 F.
- a. Another means of obtaining this data can be obtained by reading -
the' raw signals (T/C and reference junction c utput) with portable test equipment. .This data is available'in the control building'and would be accessable under all conditions should the primary and backup display devices fail.
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- b. The range of this system will be increased to one which is equal to the primary system. .One thought at this time is to incorporate into SPDS.- -
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- 4. This, system will'be revicw'ed by the human Eactors review group as a part of NUREG-0700 Ensk. ,
- 5. _ Cable Separation-
- a. The'incore T/C cables will exit the reactor cavity wall through one conduit. Outside.the reactor cavity wall but inside the containment building PAM 1 and PAM 2 incore T/C cables will be separated and routed in seismically supported conduit to separate temperature reference junctions. From the reference junctions
' to separate. containment penetrations, the incore T/C cabica will be routed in seismically supported conduit.
.b. The containment penetrations'used for PAM incore T/C cables will also be used by low and medium level nonsafety-related signal cables.
.' ' c. Outside the containment' building', the PAM 1 incore T/C cables shall be routed independently from PAM 2 cables.
- 6. Present isolation between the primary and backup channels is implemented in the form of electrical switches. The primary and backup display channels are powered by a reliable battery-backed power source.
- 7. The existing incore T/C system:is a very simple set of hardware which should, by virtue of its simplicity, be~a highly reliable and accessible system.
- 8. Same as item.7.
i' 9. Same as item 7.
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