ML20204H429

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Proposed Tech Specs 3.9.3,allowing Use of Gamma-Metrics post-accident Neutron Monitors to Provide Neutron Flux Info During Operational Mode 6
ML20204H429
Person / Time
Site: Byron, Braidwood  Constellation icon.png
Issue date: 03/22/1999
From:
COMMONWEALTH EDISON CO.
To:
Shared Package
ML20204H427 List:
References
NUDOCS 9903290073
Download: ML20204H429 (31)
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Text

. . . . . . . -. . . - . - _ . - . . . . . . . - .. .. - - . . . ~ . . _ - - .

1 ATTACHMENT B-1 MARKED-UP PAGES OF PROPOSED CHANGE

)

FOR BYRON STATION '

l i

l Revised Pages:

I 3.9.3-1 B 3.9.3-1 B 3.9.3-2 B 3.9.3-3 Pages Included for Information Only:

l l

3.9.3-2 B 3.9.3-4 I

i l

l 9903290073 990322

~

PDR ADOCK 05000454 P PDR

.. . . . . . . . . ~ . . _ _ - - - - . - . . - -. - . . - -- .. - .. ..~.-- .~., . -.- . ~.-. ~

Nuclear Instrumentation 3.9.3 J

'3.9' REFUELING OPERATIONS

~ 3.9.3_ Nuclear Instrumentation LCO 3.9.3 Two source range neutron flux monitors shall be OPERABLE.

_ APPLICABILITY: .. MODE 6.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME If WI(C A. One sou ange A.1_ Sus 3end CORE Immediately neutron flux monitor ALT ERATIONS.

inoperable.

AND A.2 Suspend _ positive Immediately reactivity additions.

A B. Two u ge B.1 Initiate action to_ Immediately neutron flux monitors restore one source

. inoperable, range neutron flux monitor to OPERABLE status.

AND B.2 Perform SR 3.9.1.1. Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> t

LBYRON - UNITS 1'& 2 3. 9. 3 - 1 Amendment @

i- .

]

i Nuclear Instrumentation 3.9.3 l

.. SURVEILLANCE REQUIREMENTS

]

SURVEILLANCE FREQUENCY I SR' 3.9.3.1 Perform CHANNEL CHECK. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> l

\

i SR 3.9.3.2 . NOTE l

Neutron detectors are excluded from CHANNEL CALIBRATION. j Perform CHANNEL CALIBRATION. 18 months ,

l

'l E

l 1

l l

l BYRON - UNITS 1 & 2 3.9.3 - 2 Amendment 106  ;

O

l l

Nuclear Instrumentation B 3.9.3

~B 3.9 REFUELING OPERATIONS >

B'3.9.3 Nuclear. Instrumentation i BASES BACKGROUND The source ra'nge neutron flux monitors are used during  ;

refueling o condition. perations The installed to monitor source the range core reactivity neutron flux monitors are part of the Nuclear Instrumentation System (NIS). These detectors are located external. to the reactor vessel and detect neutrons leaking from the core. The use of

)ortable detectors is permitted, provided the

_C0 requirements are met.

The installed (estinghou) source range neutron flux l monitors are boron trifluoride detectors operating in the t proportional. region of. the gas filled detector .

characteristic curve. The detectors monitor the neutron flux in co s per second. The instrument range covers six decades to 1E+6 cps)6 ith 7%*rTr?mchtaccuracD i (Ref. 1) heTrtstYTTGdTo1True 6 7a~ngeTalEFR6tTTci n poi ccident neutron flux monitors are enriched U-235 fission chambers operating in the ion chamber region of the gas filled detector charrteristic curve. The detectors monitor The instrument rang the neutron covers stx decades flux _(0.1 in co!'nts percps) to 1E+5_ secon[d. -

he detectors a so e contin 0ous visual incrication in the' control room to alert operators to a possible dilution accident. The NIS is  ;

designed in accordance with the criteria presented in Reference 2. If used, portable detectors must be functiona rance_

monitor _s[llv While equivalenLto multiple source the_range in_ stalled e ron NIS ux sourc monitors gre available (i.e.. four installed monitors and the f potential for the use of portable detectors), 'only two

- source range neutron flux monitors are required to be

- -- ^

{RABLE APPLICABLE Two OPERABLE source range neutron flux monitors are recuired '

SAFETY ANALYSES to provide a signal to alert the operator to unexpecter changes in core reactivity such as with a boron dilution accident (Ref. 3) or an' improperly loaded fuel assembly.

The need for a safety analysis for an uncontrolled boron dilution accident is eliminated by isolating all unborated water sources as required by LCO 3.9.2. "Unborated Water Source Isolation Valves."

BYRON - UNITS.1 & 2 B 3. 9.3 '- 1 Revisionh ,

l 1

, - ~

Nuclear -Instrumentation B 3.9.3 I i

.. BASES-

~ APPLICABLE SAFETY ANALYSES (continued) I The source range neutron flux monitordhave no s ifety -

~

unc o in noce 5 ancMot assumed to functi in during )

any UFSAR design basis accident or transient. Tie source '

range neutron flux monitors provide the only on scale

, monitoring of the neutron flux level during ref L ling.

Therefore, they. are beinc1 retained in the Tech ' cal

[Meci 0 Or,fi 9]S(c)(2)(ii cati ons fa t i }f

';if Ch = = ~t crTcn W J' _

LC0 This LC0 requires that two source range neutron. flux monitors be OPERABLE to ensure that redundant monitoring capability is-available to detect changes in core reactivity. To be OPERABLE. each monitor must provide visual indication.

APPLICABILITY In MODE 6. Owo ource range neutron flux monitors must be OPERABLE to'tfEtermine changes in core reactivity. There are no other direct means availabit to check core reactivity levels. In MODE 2 below the intermediate range r.eutron flux interlock setpoint (P-6), and in MODES 3. 4. and 5 with the Rod Control System capable of rod withdr m 1 or with all rods not fully inserted, the installed festingh_oMsource range neutron flux monitors are required to be OPERABLE by LCO 3.3.1. " Reactor Trip System (RTS) Instrumentation."

ACTIONS A.1 and A.2 With only one required source range neutron flux monitor OPERABLE. redun as been lost. Since these instruments are the only direct means of monitoring core reactivity conditions. CORE ALTERATIONS and positive reactivity additions must be-suspended immediately. Performance of Required Action A.1 or A.2 shall not preclude completion of movement of a component to a safe position or normal  ;

heatup/cooldown of the coolant volume for the purpose of '

system temperature control.

BYRON'- UNITS'l & 2 83.9.3-2 Revisionh

+- - - - - ~

Nuclear Instrumentation l B 3.9.3 BASES l ACTIONS (continued) l 8.1 and B.2 '

l With no 'e uire source range neutron flux monitor OPERABLE. 1 there are n rect means of detecting changes in core reactiv11.y. Therefore, action to restore a monitor to l OPERABLE status shall be initiated immediately and continued until a source range neutron flux monitor is restored to OPERABLE s' .us .

1 Since CORE ALTERATIONS and positive reactivity additions are l not to be made, the core reactivity condition is stabilized j until the source range neutron flux monitors are OPERABLE. -

This stabilized condition is determined by performing SR 3.9.1.1 to ensure that the required boron concentration ,

exists. i l

The Completion Time of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is sufficient to i obtain and analyze a reactor coolant sample for boron i concentration and ensures that unplanned changes in boron l concentration would be identified. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is reasonable considering the low probability of a change in core reactivity during this time period.

SURVEILLANCE SR 3.9.3.1 REQUIREMENTS SR 3.9.3.1 is the performance of a CHANNEL CHECK. which is a comparison of the parameter indicated on one channel to a similar parameter on other channels. It is based on the assumption that the two indication channels should be

~

consistent with core conditions. Changes in fuel loading and core geometry can result in significant differences '

between source range channels. but each channel should be consistent with its local conditions.

The Frequency of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is consistent with the CHANNEL CHECK Frequency specified similarly for the same instruments in LCO 3.3.1.

BYRON - UNITS 1 & 2 B 3.9.3 - 3 Revision

Nuclear Instrumentation B 3.9.3

.- BAS-ES SURVEILLANCE REQUIREMENTS (continued)

SR 3.9.3.2 SR 3.9.3.2 is the performance of a CHANNEL CALIBRATION every 18 months. This SR is modified by a Note stating that neutron detectors are excluded from the CHANNEL CALIBRATION.

The CHANNEL CALIBRATION for the source range neutron flux monitors consists of obtaining the detector discriminator curves, evaluating those curves, and comparing the curves to the manufacturer's data, The 18 month Frequency is based on the need to perform this Surveillance under the conditions that ap)1y during a plant outage. Operating experience has shown t1ese components usually pass the. Surveillance when performed at the 18 month Frequency.

REFERENCES 1. UFSAR, Table 7.5-2.

2. 10 CFR 50 Appendix A GDC 13, GDC 26. GDC 28 and GDC 29. '
3. UFSAR, Section 15.4.6.

l BYRON - ONITS 1 & 2 B 3.9.3 -4 Revision

p: _#_a, A 4 -A, _ _a 4 MJ _mme. 4J _Wm.c J aat 4 - p.4444..v ..k -Im_u . 4 _,.o-s-.a ab l

ATTACHMENT B-2 MARKED-UP PAGES OF PROPOSED CHANGE FOR BRAIDWOOD STATION Revised Pages:

3.9.3-1 B 3.9.3-1 ,

B 3.9.3-2 B 3.9.3-3 Pages included for information Only:

3.9.3-2 B 3.9.3-4 1

1 4

I i

u ,

E ,

Nuclear Instrumentation

!. 3.9.3- l l

.- .3.9. REFUELING OPERATIONS 3.9.3 : Nuclear Instrumentation l

f i j .LCO .3.9.3 Two source range neutron flux monitors shall be OPERABLE.  !

l l

l APPLICABILITY: MODE 6.

l l ACTIONS-l l CONDITION REQUIRED ACTION COMPLETION TIME l sired A ~. . Oneysourc ge A.1 Sus)end CORE- Immediately  :

l neutron flux monitor ALTERATIONS.

inoperable.

AND A.2 Suspend positive Immediately I reactivity additions, n

rc wired B. Two source range B.1. Initiate action to. Immediately  ;

neutron flux monitors restore one source  !

[ inoperable, range neutron flux

! monitor to OPERABLE l status.

AND B.2 Perform SR 3.9.1.1. Once per l 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> i

I l l l

l I

(,

i-BRAIDWOOD - UNITS 1 & 2 3.9.3 - 1 -Amendment bl l

l- j 1

.... ~.. . .. - . _ - . . . . -. - . - . - - - _ - - - .- .. . . _ - - . . . .

l Nuclear Instrumentati.on 3.9.3 i

. SggEILLANCEREQUIREMENTS SURVEILLANCE FRE0VENCY l 1

2 SR 3.9.3.1 Perform CHANNEL CHECK. 12. hours l

SR 3.9.3.2 .

NOTE -

l Neutron detectors are excluded from CHANNEL i

! CALIBRATION.

Perform CHANNEL CALIBRATION. 18 months I

i 4

I l

I l

l BRAIDWOO' D - UNITS l'& 2 3.9.3 - 2 Amendment 98-1

l Nuclear Instrt' mentation I B 3.9.3

, B 3.9. REFUELING OPERATIONS I

B 3.9.3 Nuclear Instrumentation I i

' BASES BACKGROUND: The source range neutron flux monitors are used during refueling operations to monitor the core reactivity condition. The installed source range neutron flux monitors are part of the Nuclear Instrumentation. System (NIS). These detectors are located external to the reactor vessel and detect neutrons leaking from the core. The use of Jortable detectors is permitted, provided the l

_C0 requirements are met, j The installedkstinghouse)) source range neutron flux monitors are boron trifluoride detectors operating in the l proportional region of the gas filled detector  !

characteristic curve.. The detectors monitor the neutron i flux in c u s per second h 'ns ru e range covers six l decades 1 to 1E+6 cps) " + ' " - + acc"rac' l (Ref. 1 ) ._ e wired source range Gamma-Metrics pos ccident neutron flux monitors are enriched U-235 fission .l chambers operating in the ion chamber region _of the gas ~ i filled detector characteristic curve. The detectors monitor  !

h the neutron flux in counts per-second. Th instrument rana  !

gvers six decades (0.1 to 1E+5 cos). e cFetectors also  ;

provide continuous visuaT indication in the control room to .

I alert operators to a possible dilution accident. The NIS is designed in accordance with the criteria presented in j Reference 2. If used, portable detectors must be functional 11 equivalent to the installed NIS source range I monitors _._1 While multipTGTource F6fige~nTtitToFNTax 6 monitor I re available (i.e., four installed monitors and the otential for the use of portable detectors), only two source range neutron flux monitors are required to be OPERAB - = ~ -

APPLICABLE Two OPERABLE source range neutron flux monitors are recuired I SAFETY ANALYSES to provide a signal to alert the operator to unexpectec changes in core reactivity such as with a boron dilution accident (Ref. 3) or an improperly loaded fuel assembly.

The need for a safety analysis for an uncontrolled boron dilution-accident is eliminated by isolating all unborated i

, water sources as required by LCO 3.9.2 "Unborated Nater Source Isolation Valves."

, Me

! BRAIDWOOD - UNITS 1 & 2 B 3.9.3 - 1 Revision

__ ~. _ _ _ _. _. . _ ._ - _ _ _ _ _ .._.._.-_. _ _.-._ .._... _ _ _

.s

  • Nuclear Instrumentation B 3.9.3 l

.. BASES'-

APPLICABLE SAFETY-ANALYSES (continued)

The source r nge neutLon flux mon _itQr.sjiave no sad fun f any'UFSAR nBtion in design oe and are not assumed to function during basis accident or transient. The source 1 range neutron flux monitors provide the only on-scale '

monitoring of the neutron flux level during refueling.

Therefore, they are beina retaineti Tc ical ifications_My Criterion 3 cf

- .., 50.35(c)(2)(ii) f --

.LCO This LC0 requires that two source range neutron flux monitors be OPERABLE to ensure that redundant monitoring capability is available to detect changes in core reactivity. To be OPERABLE. each. monitor must provide visual indication.

1 APPLICABILITY In MODE 6, w ot;rce range neutron flux monitors must be l OPERABLE t ermine changes in core reactivity. -There are  ;

no other direct means available to check core reactivity levels. In MODE 2 below the "ntermediate range neutron flux  !

interlock setpoint (P-6), and in MODES 3, 4. and 5 with the 1 Rod Control System capable of iod withdr h all  !

rods not fully inserted, the installed estinghouse source l range neutron flux monitors are required to be OPERABLE by l LC0 3.3.1, " Reactor Trip System (RTS) Instrumentation."

i i

ACTIONS A.1 and A.2 With only onehsource range neutron flux monitor OPERABLE redunaancy nas been lost. Since these ine uments  ;

are the only direct means of monitoring core reactivity l conditions, CORE ALTERATIONS and positive reactivity additions must be suspended immediately. Performance of Required Action A.1 or A.2 shall not preclude completion of movement of a component to a safe position or normal i heatup/cooldown of the coolant volume for the purpose of I system temperature control.

BRAIDWOOD - UNITS 1 & 2 B 3.9.3 - 2 Revisionh

Nuclear Instrumentation B 3.9.3

,- BASES ACTIONS (continued)

B.1 and B.2 With no require ource range neutron flux monitor OPERABLE.

there ar rect means of detecting changes in core reactivity. Therefore, actica to restore a monitor to OPERABLE status shall be initiated immediately and continued until a source range neutron flux monitor is restored to OPERABLE status.

Since CORE ALTERATIONS and positive reactivity additions are not to be made, the core reactivity condition is stabilized until the source range neutron flux monitors are OPERABLE.

This stabilized condition is determined by performing SR 3.9.1.1 to ensure that the required boron concentration exists.

The Completion Time of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is sufficient to  !

obtain and analyze a reactor coolant sample for boron l concentration and ensures that unplanned changes in boron concentration would be identified. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is reasonable, considering the low probability of a change in core reactivity during this time period.

SURVEILLANCE SR 3 9.3.1 REQUIREMENTS SR 3.9.3.1 is the performance of a CHANNEL CHECK. which is a comparison of the parameter indicated on one channel to a similar parameter on other channels. It is based on the l assumption that the two indication channels should be consistent with core conditions. Changes in fuel loading and core geometry can result in significant differences i between source range channels, but each channel should be consistent with its local conditions.

j The Frequency of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is consistent with the CHANNEL CHECK Frequency specified similarly for the same instruments in LCO 3.3.1.

BRAIDWOOD - UNITS 1 & 2 B 3.9.3 - 3 Revision 2

Nuclear Instrumentation B 3.9.3

.- BASES SURVEILLANCE REQUIREMENTS (continued)

SR 3.9.3.2 SR 3.9.3.2 is the 3erformance of a CHANNEL CALIBRATION every 18 months. This S1 is modified by a Note stating that neutron detectors are excluded from the CHANNEL CALIBRATION.

The CHANNEL CALIBRATION for the . source range neutron flux monitors consists of obtaining the detector discriminator curves, evaluating those curves. and comparing the curves to the manufacturer's data. The 18 month Frequency is based on the need to perform this Surveillance under the conditions that ap]ly during a plant outage. Operating experience has shown t1ese components usually pass the_ Surveillance when performed at the 18 month Frequency.

REFERENCES 1. UFSAR. Table 7.5-2.

2. 10 CFR 50, Appendix A. GDC 13. GDC 26. GDC 28. and GDC 29.
3. UFSAR, Section 15.4.6.

BRAIDWOOD - UNITS 1 & 2 B 3.9.3 -4 Revisionh

ATTACHMENT B-3 INCORPORATED PROPOSED CHANGE, TYPED PAGES, FOR BYRON STATION Revised Pages:

3.9.3-1 l B 3.9.3-1 i B 3.9.3-2 B 3.9.3-3 8 3.9.3-4 i

Pages included for information Only: 1 3.9.3-2 l

w. _- _ _ _ - _ _ _ _ _ _ __ __ -

- . - . - - . . . - . - - - - . . - -.. -._ - . _ ... .~. - _~

L Nuclear Instrumentation ,

l 3.9.3 3,9 REFUELING OPERATIONS 3.9-3 Nuclear Instrumentation -

l LCO'3.9.3 Two source range neutran ilux monitors shall be OPERABLE. ,

l l

H APPLICABILITY: MODE 6.

I  :

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One required source A.1 Suspend CORE Innediately l range neutron flux ALTERATIONS.

l- monitor inoperable.

l AND A.2 Suspend positive Immediately L reactivity additions.

L B. Two required source B.1 Initiate action to Immediately. l l ' range neutron flux - restore one source

! monitors inoperable. range neutron flux t

monitor to OPERABLE status.

AND B.2 Perform SR 3.9.1.1. Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> l

l-l I

1

  • BYRON! ; UNITS 1 & 2 3 9.3 '1 Amendment i

Nuclear Instrumentation 3.9.3

,- SURVEILLANCE' REQUIREMENTS

+

SURVEILLANCE FREQUENCY SR 3.9.3.1- Perform CHANNEL CHECK. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />

.SR 3.9.3.2 NOTE ,

' Neutron detectors are excluded from CHANNEL l CALIBRATION.  ;

Perform CHANNEL CALIBRATION. 18 months l

l

)

l 1

l 1

l BYRON - UNITS 1 & 2 3.9.3 - 2 Amendment 106

e .. ,

Nuclear Instrumentation c B 3.9.3 ,

.- B.3.9 REFUELING OPERATIONS  !

B 3.9.3 Nuclear. Instrumentation l BASES BACKGROUND The source range neutron flux. monitors are used during refueling operations to monitor-the core reactivity condition. The installed source range neutron flux monitors are part of the Nuclear Instrumentation System (NIS). These detectors are located external to the reactor vessel and detect neutrons leaking from the core. The use of Jortable detectors is permitted, provided the C0 requirements are met. i

'.The installed Westinghouse source range neutron flux monitors are boron trifluoride detectors operating in the proportional region of the gas filled detector l characteristic curve. The detectors monitor the neutron 1 flux in counts aer second. The instrument range covers six decades (1 to 1E+6 cps) (Ref.1). The installed source range Gamma-Metrics post accident neutron flux monitors'are enriched U-235' fission chambers operating in the ion chamber region of the gas filled detector characteristic curve. The detectors monitor the neutron flux in counts per'second.

The instrument range covers six decades (0.1 to IE+5 cps).

The detectors also provide continuous visual indication in the control room to alert operators to a possible dilution accident. The NIS is designed in accordance with the 1 criteria presented in Reference 2. If used, i portable detectors must be functionally equivalent to the  ;

installed NIS source range monitors. While multiple source j range neutron flux monitors are available (i.e., four i installed monitors and the potential for the use of '

portable detectors), only two source range neutron flux  !

monitors are required to be OPERABLE.

-l i

BYRON . UNITS 1 & 2 - B 3.9.3 - 1 Revision 2 l

Nuclear Instrumentation B 3.9.3

.- BASES I APPLICABLE- Two OPERABLE source range neutron flux monitors are recuired

SAFETY ANALYSES to provide a signal to alert the operator to unexpectec f

changes in core reactivity such as with a boron dilution accident (Ref. 3) or an improperly loaded fuel assembly.

The need for a safety analysis for an uncontrolled boron

, dilution accident is eliminated by isolating all unborated water sources as required by LCO 3.9.2. "Unborated Water Source Isolation Valves."

The source range neutron flux monitors have no safety function in MODE 6 and are not assumed to function during ,

any UFSAR design basis accident or transient. The source I range neutron flux monitors provide the only on-scale '

monitoring of the neutron flux level during refueling.

Therefore they are being retained in the Technical Specifications.

LCO This LCO requires that two source range neutron flux monitors be OPERABLE to ensure that redundant monitoring capability is available to detect changes in core reactivity. To be OPERABLE. each monitor must provide visual indication.  ;

APPLICABILITY In MODE 6. two source range neutron flux monitors must be l OPERABLE to determine changes in core reactivity. There are no other direct means available to check core reactivity ,

levels. In MODE 2 below the intermediate range neutron flux '

interlock setpoint (P-6), and in MODES 3. 4. and 5 with the Rod Control System capable of rod withdrawal or with all rods not fully inserted. the installed Westinghouse source l range neutron flux monitors are required to be OPERABLE by LC0 3.3.1. " Reactor Trip System (RTS) Instrumentation."

BYRON - UNITS 1 & 2 B 3.9 3 -2 Revision 2 l

Nuclear Instrumentation i B 3.9.3 i

. BASES T

-ACTIONS A.1 and A.2 )

With only one required source _ range neutron flux monitor l !

OPERABLE, redundancy has been lost. Since these instruments are the only direct means of monitoring core reactivity.

conditions. CORE ALTERATIONS and positive reactivity additions must be suspended.immediately. Performance of 1 Required Action A.1 or A.2 shall not preclude completion of '

, movement of a component to a safe position or normal l l heatup/cooldown.of the coolant volume for the purpose of 1 i system' temperature control.

B.1 and B.2 With no , required source range neutron flux monitor OPERABLE, l there are no direct means of detecting changes in core

reactivity. Therefore. action to restore a monitor to t

OPERABLE status shall be initiated immediately and continued until a source range neutron flux monitor is restored to OPERABLE status.

Since CORE' ALTERATIONS and positive reactivity additions are not to be made, the core reactivity condition is stabilized until1the source range neutron flux monitors are OPERABLE.

l This stabilized condition is determined by performing L SR 3.9.1.1 to ensure that the required boron concentration j exists.

l l The Completion Time of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is sufficient to  !

l obtain and analyze a reactor coolant sample for boron  ;

, concentration and ensures that unplanned changes in boron l concentration would be identified. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is )

i reasonable, considering the low probability of a change in ,

core reactivity during this time period. J l .

i 1

! l 1.

t l -BYRON - UNITS 1 & 2 B 3.9.3 - 3 Revision 2 L

l l

Nuclear Instrumentation-B 3.9.3-

.- /3ASES

-SURVEILLANCE SR 3.9.3.1  :

REQUIREMENTS- .

, SR 3.9.3.1 is the performance of a CHANNEL CHECK, which is a i comparison of the parameter indicated on one channel to a.

.similar parameter on'other ~ channels. It is based on the assumption that the two indication channels should be.

consistent with core conditions. Changes in fuel loading j and core geometry- can result in significant differences between. source' range channels, but each channel. should be consistent with its: local conditions.  ;

~

The Frequency of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is consistent with the CHANNEL CHECK Frequency specified.similarly for the same instruments in LCO 3.3.1.  :

SR 3.9.3.2 SR 3.9;3.2 is the performance of a CHANNEL. CALIBRATION every

18. months. This' SR is modified by a Note stating that neutron detectors are excluded from the CHANNEL CALIBRATION.

The CHANNEL CALIBRATION for the source range neutron flux monitors consists of obtaining-the detector discriminator curves, evaluating' those curves, and comparing the curves to the manufacturer's data. The 18 month Frequency is based on the need to perform this Surveillance under.the conditions-

'that ap)1y during a. plant outage. 0perating experience has shown t1ese components usually pass the Surveillance when performed at the 18 month Frequency. .

REFERENCES 1. UFSAR, Table 7.5-2. l

2. 10 CFR 50, Appendix A. GDC 13, GDC 26, GDC 28. and j GDC 29.
3. UFSAR Section 15.4.6.

)

BYRON - UNITS 1 & 21 B 3.9.3 - 4 Revision 2. l

_ _ _ _ _ _ _ _ . . _ ~ . . . ___ _

ATTACHMENT B-4 INCORPORATED PROPOSED CHANGE, TYPED PAGES, FOR BRAIDWOOD STATION Revised Pages:

3.9.3-1 B 3.9.3-1 B 3.9.3-2 B 3.9.3-3 B 3.9.3-4 Pages included for Information Only:

3.9.3-2

Nuclear Instrumentation 3.9.3

.- 3.9' REFUELING'0PERATIONS

'3.9.3 ' Nuclear. Instrumentation- -

t-LC0 3.9.3 Two source range neutron flux monitors shall be OPERABLE. i APPLICABILITY: MODE 6.

4 ACTIONS CONDITION- REQUIRED ACTION- COMPLETION TIME A. One required source A.1 Suspend CORE Immediately l ,

range neutron flux ALTERATIONS.

monitor inoperable.

AND ,

A.2 Suspend positive -Immediately reactivity additions.

B. Two required source B.1 Initiate action to Immediately l range neutron flux restore one source monitors inoperable, range neutron flux monitor to OPERABLE status.

AND B.2 Perform SR 3.9.1.1. Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> P

4 BRAIDWOOD - UNITS 1 & 2 3. 9. 3 - 1~ Amendment l

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i Nuclear Instrumentation 3.9.3

. SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.9'.3.1 Perform CHANNEL CHECK. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 1 l

SR 3.9.3.2 NOTE Neutron detectors are excluded from CHANNEL CALIBRATION.

Perform CHANNEL CALIBRATION. 18 months t

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l BRAIDWOOD - UNITS 1 & 2 3.9.3 - 2 Amendment 98 4

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Nuclear Instrumentation B 3.9.3 I .- 'B.3.9 REFUELING OPERATIONS h B 3.9.3 Nuclear Instrumentation BASES' ,

BACKGROUND- The source range neutron flux monitors are used during j refueling operations to monitor the core reactivity' condition. The installed source range neutron. flux monitors are. part of the Nuclear Instrumentation System (NIS). These detectors are located external to the reactor vessel and l

detect neutrons leaking from the core. The use of. ';

3ortable detectors is permitted, provided the

_CO requirements are met. ,

The installed Westinghouse source range neutron flux l monitors are boron trifluoride detectors operating in the proportional region of the gas filled detector characteristic curve. The detectors monitor the neutron flux in counts per second. The instrument range covers six decades (1 to 1E+6 cps) (Ref. 1). The installed source i L range Gamma-Metrics post accident neutron flux monitors are l

! enriched U-235 fission chambers operating in the ion chamber  !

l region of the gas filled detector-characteristic curve. The

' detectors monitor the neutron flux in counts per second. l The instrument range covers six decades (0.1 to 1E+5 cps).  !

The detectors also provide continuous visual indication in the control room to alert operators to a possible dilution accident. The NIS is designed in accordance with the l criteria presented in Reference 2. If used, L portable detectors must be functionally equivalent to the l installed NIS source range monitors. While multiple source l range neutron flux monitors are available (i.e., four installed monitors and the potential for the use of

, portable detectors) only two source range neutron flux l monitors are required to be OPERABLE.

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1 Nuclear Instrumentation '

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' APPLICABLE TwoLOPERABLE. source range neutron flux monitors are recuired l SAFETY ANALYSES to provide a signal to alert the operator to unexpectec l changes in core reactivity such as with a boron dilution l accident (Ref. 3) or an improperly loaded fuel assembly. l The need .for a safety analysis for an uncontrolled boron  !

dilution accident is eliminated by isolating all unborated '

water sources as required by LC0 3.9.2, "Unborated Water Source Isolation Valves."

The source range neutron flux monitors have no safety function in MODE 6 and are not assumed to function during any UFSAR design basis accident or transient. The source range neutron flux monitors provide the only on-scale monitoring of the neutron flux level during refuelin, l Therefore, they are being retained in the Technical Specifications.

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.LC0 This LC0 requires that two source range neutron flux I monitors be OPERABLE to ensure that redundant monitoring 4 l capability is available to detect changes in core -!

l reactivity. To be OPERABLE, each monitor must provide t

visual indication.

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APPLICABILITY In MODE 6. two source range neutron flux monitors must be OPERABLE to determine changes in core reactivity. There are no other direct means available to check core reactivity levels. In MODE 2 below the intermediate range neutron flux 4 interlock setpoint (P-6), and in MODES 3, 4, and 5 with the Rod Control System capable of rod withdrawal or with all rods not fully inserted, the installed Westinghouse source range neutron flux monitors are required to be OPERABLE by LCO 3.3.1 " Reactor Trip System (RTS) Instrumentation."

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Nuclear Instrumentation B 3.9.3 4

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ACTIONS A.1 and AL2 t With.only.one required source range neutron flux monitor l

' OPERABLE, redundancy has been lost. Since these instruments are the only direct means of monitoring core reactivity

, conditions. CORE ALTERATIONS and positive reactivity F additions must be suspended immediately. Performance of Required Action A.1 or A.2 shall not preclude completion of movement of a component to a safe position or normal 1 i heatup/cooldown of the coolant volume for the purpose of I system temperature control. j B.1 and B.2  ;

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! With no required source range neutron flux monitor OPERABLE. I l 4 there are no direct means of detecting changes in core i reactivity. Therefore, action to restore a monitor to 3 i OPERABLE status shall be initiated immediately and continued '

until a source range neutron. flux monitor is restored to OPERABLE status.  !

Since CORE ALTERATIONS and positive reactivity additions are

, not to be made, the core reactivity condition is stabilized until the source range neutron flux monitors are OPERABLE.

This stabilized condition is determined by performing 4

SR 3.9.1.1 to ensure that the required boron concentration l exists, i L The Completion Time of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is sufficient to j obtain and analyze a reactor coolant sample for boron

concentration and ensures that unplanned changes in boron 1 concentration would be identified. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is ,

! reasonable, considering the low probability of a change in i

core reactivity during this time period.

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!- Nuclear Instrumentation B 3.9.3

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!- . SURVEILLANCE SR 3.9.3.1 i REQUIREMENTS SR 3.9.3.1 is the performance of a CHANNEL CHECK. which is a e

comparison of the parameter indicated on one channel to a similar parameter on other channels. It is based on the assumption that the two indication channels should be  !

consistent with core conditions. Changes in fuel loading

'; and core geometry can result in significant differences '

between source range channels, but each channel should be -

. consistent with its local conditions.

l The Frequency of-12 hours is consistent with the CHANNEL CHECK Frequency specified similarly for the same instruments in LC0 3.3.1. .

I SR 3.9.3.2 4

! SR 3.9.3.2 is the performance of a CHANNEL CALIBRATION every i

'18 months. This SR is modified by a Note stating that

neutron detectors are excluded from the CHANNEL CALIBRATION.

The CHANNEL CALIBRATION for the source range neutron flux

-monitors consists of obtaining the detector discriminator

curves.. evaluating those curves, and comparing the curves to
the manufacture 's data. The 18 month Frequency is based on ,

the need to perform this Surveillance under the conditions 1

. that ap)1y during a plant outage. Operating experience has shown t1ese components usually pass the Surveillance when i performed at the 18 month Frequency.

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. REFERENCES 1. UFSAR Table 7.5-2.

2. 10 CFR 50 -Appendix A. GDC 13. GDC 26. GDC 28. and GDC 29.

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3. UFSAR. Section 15.4.6.

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..o e ATTACHMENT C IM ORMATION SUt PORTING A FINDING OF NO SIGNIFICANT HAZARDS CONSIDERATION According to 10 CFR 50.92(c), a proposed amendment to an operating license involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not:

Involve a significant increase in the probability of occurrence or consequences of an accident previously evaluated; Create the possibility of a new or different kind of accident from any previously analyzed; or involve a significant reduction in a margin of safety.

Pursuant to 10 CFR 50.90, Comed proposes to amend Appendix A, Technical Specifications, of Facility Operating Licenses NPF-37, NPF-66, NPF-72, and NPF-77. The proposed change allows the use of the Gamma-Metrics Post Accident Neutron Mc.:itors (PANMs) to provide neutron flux information during Operational Mode 6. The change revisa Technical Specification 3.9.3, " Nuclear instrumentation," to insert the word "requirea' into Conditions A and B to address the allowance to use any combination of the Westinghouse and/or Gamma-Metrics PANM source range neutron flux monitors.

Information supporting the determination that the criteria set forth in 10 CFR 50.92 are met for this amendment request is provided below.

Does the proposed chnge involve a significant increase in the probability or consequences of an accident previously evaluated?

The installed Westinghouse source range neutron flux monitors are boron trifluoride detectcrs operating in the proportional region of the gas filled detector characteristic curve.

The detectors monitor the neutron flux in counts per second. The instrument range covers six decades (i.e.,1 to 1E06 counts per second (cps)). The installed source range Gamma-Metrics post accident neutron flux monitors (PANMs) are enriched U-235 fission chambers operating in the ion chamber region of the detector characteristic curve. The detectors monitor the neutron flux in counts per second. The instrument range covers six decades (i.e.,0.1 to 1E05 cps). The detectors provide continuous visualindication in the Main Control Room (MCR.) Both the Westinghouse and Gamma-Metrics PANM neutron detectors are designed in accordance with 10CFR50 Appendix A, General Design Criterion (GDC) 13, " Instrumentation and control," and GDC 29, " Protection against anticipated operational occurrences," and are functionally equivalent for this application.

The Technical Specifications Bases state that two operable source range neutron flux monitors are required to provide a signal to alert the operator to unexpected changes in core reactivity such as with a boron dilution accident or an improperly loaded fuel assembly. The use of source range neutron flux monitors, either Gamma-Metrics PANMs or Westinghouse, has no effect on the, probability of a dilution accident or an improperly loaded fuel assembly, because the source range neutron flux monitors are not in any way the initiators of or precursor to either accident.

The use of source range neutron flux monitors, either Gamma-Metrics PAMNs or Westinghouse, has no effect on the consequences of a dilution accident or an improperly Page 1 of 2 L

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ATTACHMENT C INFORMATION SUPPORTING A FINDING OF NO SIGNIFICANT HAZARDS CONSIDERATION loaded fuel assembly. The need for a safety analysis for an uncontrolled boron dilution accident is eliminated by isolating all unborated water sources as required by LCO 3.9.2, "Unbo.sted Water Source Isolation Valves." Thus boron dilution is not considered a credible accident during refueling.

UFSAR Section 15.4.7 does not credit the source range neutron flux monitors for prevention or detection of the improperly loaded fuel assembly. It instead credits administrative procedures (i.e., nuclear component transfer lists, core inventory verification, etc.) implemented during fuel loading, if a fuel assembly loading error occurred, it would be detected by a flux map, or the perturbations of the power distribution will be sufficiently small to be within the allowable uncertainties.

Therefore this proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

Does the proposed change create the possibility of a new or different kind of accident from any accider.t previously evaluated?

The proposed change to Technical Specification 3.9.3 does not involve any physical alteration of plant systems, structures, or components, or changes in parameters goveming plant operation. This change will not result in a significant reduction in monitoring capability since both the Westinghouse and Gamma-Metrics PANM source range neutron flux monitors are functionally equivalent and both are Safety Category I (Class 1E) systems. These source range instrumentation systems are for monitoring neutron flux and criticality assessment. They are not relied upon to initiate automatic accident mitigation in Operational Mode 6. Therefore, the proposed change does not create the possibility of a i new or different kir d of accident from any previously evaluated.

Does the proposed change involve a significant reduction in a margin of safety?

The proposed change will still maintain the requirement for two sotace range neutron flux monitors for visual monitoring of core reactivity as currently discussed in the Bases for the affected Technical Specifications. The Gamma-Metrics PANMs use fission chambers as 5

detectors that have a sensitiv .y of 4 cps / neutron-volt (cps /nv) for thermal neutrons and 2 cps /nv for fast neutrons. The Westinghouse source range neutron flux monitors have a sensitivity of 13 eps/nv. The Gamma-Metric.s PANMs have a comparable range and j accuracy (i.e., range of 0.1 to 1E05 cps with an accuracy of 2% of full scale) to that of the l Westinghouse source range neutron flux monitors (i.e.,1 to 1E+6 cps with an accuracy of 3% of full scale). The fact that the Gamma-Metrics PANMs do not cover the range of 1E05 to 1E06 cps is insignificant in Operational Mode 6 due to the low count rates expected.

Therefore, these changes do not involve a significant reduction in the margin of safety. j l

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  • ATTACHMENT D INFORMATION SUPPORTING ENVIRONMENTAL ASSESSMENT

, Comed has evaluated this proposed operating license amendment request against the criteria for identification of licensing and regulatory actions requiring environmental assessment in accordance with 10 CFR 51.21. Comed has determined that this proposed license amendment request meets the criteria for a categorical exclusion set forth in 10 CFR 51.22(c)(9) and as such, has determined that no irrevereh consequences exist in accordance with 10 CFR 50.92(b). This determination is based m the fact that this change ,

is being proposed as an amendment to a license issued pursuant to 10 CFR 50 that l changes a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or that changes an inspection or a surveillance requirement, and the amendment meets the following specific criteria.

(i) The amendment involves no significant hazards consideration. I As demonstrated in Attachment C, this proposed amendment does not involve any significant hazards consideration.

(ii) There is no significant change in the types or significant increase in the amounts of ,

any effluent that may be released offsite. l The proposed change is limited to source range neutron monitoring capability during Operational Mode 6. This change does not allow for an increase in unit  !

power level, does not increase the production, nor alter the flow path or method of disposal of radioactive waste or byproducts. Therefore, the proposed change does not affect actual unit effluents (iii) There is no significant increase in individual or cumulative occupational radiation exposure.

The proposed changes will not result in changes in the operation or configuration of the facility. There will be no change in the level of controls or methodology used for processing of radioactive effluents or handling of solid radioactive waste, nor will the proposal result in any change in the normal radiation levels within the plant.

Therefore, there will be no increase in individual or cumulative occupational  !

radiation exposure resulting from this change.

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