ML20078R813

Proposed Changes to Tech Specs 3.10 & 4.10 to Allow Loading of Four Irradiated Fuel Assemblies Around Each Source Range Monitor as Initial Step in Fuel Core Reload

ML20078R813
Person / Time
Site:	Browns Ferry
Issue date:	11/07/1983
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20078R808	List: ML20078R804 ML20078R813
References
NUDOCS 8311150306
Download: ML20078R813 (16)

Text

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v ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION REVISIONS BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 (TVA BFNP TS 193) 9311150306 8311070500025 ppR ADOCK P

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PROPOSED UNIT 1 SPECIFICATIONS

b.

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LIMifiv. coMntflawss rot OPERAftog stntytttLusCI REOUIREWINTS 3.10.A Refuellen laterloche 4.10.4 3afaeltnk Interloc_h_e being withdrawn may be bypa s s e d on a wi t hd r onna U

control red p ter the fiel assemellee in th.e cell centeinima (sen-trolled by) that ow t rol red have been re-moved from the reester core. All other re-fwltog interises shell be eretabis.

B.

Core Monitoring 3.

core 'venttortnt 1.

During core alterations, except, Frior to' =ekins any siterat tane as in 3.10.B.2, tvo SPJt's shall to the core the su's shall be faseti mally teeted and checked be operable, in or adjacent to any quadrant where, f u.fl or control I

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s her, while reutred to be rods are ' being rnoved.

For an SPJ1

• *I to be considered operable, the f ollowing shall be sa tisfied:

&&d daily for response except as specified in 3.10.B.l.b.2.

a.-

Thic SPJi sha

• 1 5e inserted to e

the normal operating Icvel.

(Use of special moveable, dunking type detre tore elurins initial f tml loading and major core altera:1ons in place of norma l detec tors is per-v missible as long ar. the detector is connected to the norinal SFJi circuit.)

b.)

The SRM shall have a minimum of 3 cps with all rods fully inserted in the

-core, if one or more fuel assemblies are in the core, or, b.2 During a full core reload where both irradiated and fresh fuel is being loaded, SRM's (FLC's) may have a count rate of <3 cps provided that the SRM's are response checked at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> with a neutron source until >3 cps can be maintained, and

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provided also that the core is loaded in a spiral sequence only,or j

305 v

LIMITING CONDITIONS FOR OPERATION SURVEILIANCE REQUIREMENTS 3.10.B b.3 During a full core reload where both irradiated and fresh fuel are being loaded, four (4) irradi-ated fuel assemblies will be placed adjacent to each SRM to establish a count rate of >3 cps, provided each SRM is functionally tested prior to adjacent fuel loading, a neutron response is observed as the adjacent fuel is loaded, and the core is loaded in a spiral sequence only after the SRM adjacent fuel loading.

i 305A

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3,10 BASES REFERENCES e

1.

Refueling interlocks (BFNP FSAR Subsection 7.6)

B.

Core Monitoring The SRM's are provided to monitor the core during periods of station shutdown and to station startup.' guide the operator during refueling operations and Requiring two operable SRM's in or adjacent to any core _ quadrant where fuel or control rods are being moved assures ade-quate monitoring of that quadrant during such alterations. The require-ment of 3 counts per second provides assurance that neutron flux is being monitored and ensures that startup is conducted only if the source range f)ux Icvel is above the minimum assumed in the control rod drop accident.

During a full core reload SRM/FLC (Fuel Loading Chamber) operability will be verified using a portable external auurce at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> until sufficient fuel has been loaded to maintain 3 cps. A large number of fuel assemblies will not be required to maintain 3 cps.

This increased surveillanc'e rate assures proper dacector operability until that time.

During a full core reload, irradiated fuel may be placed adjacent to each SRM to maintain a count rate >3 cps. Four (4) irradiated fuel assembliss will be placed in the four adjacent fuel locations to each SRM to establish the >3 eps count rate. The response of each SRM to the adjacent fuel loading will demonstrate neutron response. Each SRM will be functionally tested prior to loading the adjacent fuel assemblies. This precludes the use of FLC's as mandatory for a full core reload.

Under the special condition of removing the full core with all control rods inserted and electrically disarmed, it is permissible to allow SRM count rate to decrease below 3 cps. All fuel moves during core unloading will reduce reactivity. It is expected that the SRM's will drop below 3 cps before all of the fuel is unloaded.

Since there will be no reactivity additions during this period, the low number of counts will not present a hazard. When all of the fuel has been removed to the spent fuel storage pool, SRM's will no longer be required. Requiring the SRM's to be functionally tested prior to fuel removal assures that the SRM's will be operable at the start of fuel removal. The daily response check of the SRM's ensures their continued operability until the' count rate diminishes due to fuel removal. Control roda in ec11s from which all fuel has been removed and which are outsida the periphery of the then existing fuel matrix may be armed electrically and moved for maintenance purposes during full core removal, provided all rods that control fuel are fully inserted and electrically disarmed.

REFERENCES 1.

Neutron Manitoring System (BFNP FSAR Subsection 7.5) 2.

Morgan, W. R.,"In-Core Neutron Monitoring System for General Electric Boiling Water Reactors," General Electric Company, Atomic Power Equipment Department, November 1968, revised April 1969 (APED-5706) v 311

e PROPOSED UNIT 2 SPECIFICATIONS l

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LIMIT ime emnt flows rea oPKRAflot SU1rvt11.LusCT Rt0312tMIN 5 1.10.A Refueltag Interloche 4.10.A Safinatint Interlocke being withdrawn may be bypassed on a withdrawn control red af ter the fuel assemeltee la th.a cell conteisina (sen-trolled by) that een-trol eed have been re-seved from the reseter cere. All etkaf re-fuelleg 1statlede shall be operable.

B.

Core Ment rorins:

3.

Care Mont to rtne 1.

During core alterations, except.

Frist to makins any siterattans as in 3.10.B.2. two SPJt's shall to the core the sut's shall be fonctionally tested and checked be operable, in or adjacent to any quadrant where f u.f1 or control I*f "'"E"

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rods are being,' moved.

For an SFli aher, w 11e rev{ red to be

• "I to be considered operable the following shall be satisfied:

&M daily for response except as specified in 3.10.B.1.b.2.

a.- Th[e S10! shall be inserted to e

the normal operating Icvel.

(Use of special moveable.

dunking type detector = during initial fuel loading and majcr core aircrations in place of normal Jetectors is per-V missible as long ar the detector is connec t ed to the normal SRM circuit.)

b.1 The SRM shall have a minimum of 3 cps with all rods fully inserted in the core, if one or more fuel assemblies are in the core, or, b.2 Nring a full core reload where both irradiated and i

fresh fuel is being loaded, SRM's (FLC's) may have a cour.c rate of <3 cps provided that the Sie!'s are response checked at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> with a neutron source until >3 cps can be maintained, and

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provided also that the core is loaded in a spiral I

sequence only,or j

305 s

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LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.10.B b.3 During a full core reload where both irradiated and fresh fuel are being loaded, four (4) irradi-ated fuel assemblies will be placed adjacent to each SRM to establiah a count rate of >3 cps, provided each SRM is functionally tested prior to adjacent fuel loading, a neutron response is observed as the adjacent fuel is loaded, and the core is loaded in a spiral sequence only af ter the SRM adjacent fuel loading.

w b

305A

.l 3.10 BASES REFERENCES e

1.

Refueling interlocks (BFNP FSAR Subsection 7.6) 8.

Core Monitoring The SRM's are provided to monitor the core during periods of station shutdown and to station startup.* guide the operator during refueling operations and Requiring two operable SRM's in or adjacent to any core quadrant where fuel or control rods are being moved as ures ade-quate monitoring of that quadrant during such alterations. The require-ment of 3 counts per second provides assurance that neutron flux is being monitored and ensures that startup is conducted only if the sourec range flux level is above the minimum assumed in the control rod drop accident.

During a full core reload SN!!/FLC (Fuel Loading Chamber) operability will be verified using a portable external source at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> until sufficient fuel has been loaded to maintain 3 cps. A large number of fuel assemblies will r.ot be required to maintain 3 cps.

This increased surveillance rate assures proper detector operability until that time.

During a full core reload, irradiated fuel may be placed adjacent to each SRM to maintain a count rate >3 cps. Four (4) irradiated fuel assemblies will be placed in the four adjacent fuel locatiorn to each SRM to establish the >3 cps count rate. The response of each SRM to the adjacent fuel loading will demonstrate neutron response. Each SRM will be functionally tested prior to loading the adjacent fuel assemblies. This precludes the use of FLC's as mandatory for a full core reload.

Under the special ccadition of removing the full core with all control rods inserted and electrically disarmed, it is permissible to allow SRM count rate to decrease below 3 cps.

All fuel moves

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during core unloading will reduco reactivity. It is expected that the SRM's will drop below 3 cps before all of the fuel is unloaded.

Since there will be no reactivity additions during this period, the low number of counts will not present a hazard. When all of the fuel has been removed to the spent fuel storage pool, SRM's will no longer be required. Requiring the SRM's to be functionally tested prict to fuel removal assures that the SRM's will be operable at the start of fuel removal. The daily response check of the SRM's ensures their continued operability until the' count rate diminishes due to fuel removal. Control rods in cells from which all fuel has been removed and which are outside the periphery of the then existing fuel matrix may be armed electrically and moved for maintenance purposes during full core removal, provided all rods that control fuel are fully inserted and electrically disarmed.

REFERENCES 1.

Neutron Manitoring System (BFNP FSAR Subsection 7.5) 2.

Morgan, W. R. "In-Core Neutron Monitoring System for General Electric Boiling Water Reactors," Conceal Electric Company, Atomic Power Equipment Department, November 1968, revised April 1969 (APED-5706) v 311

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l PROPOSED UNIT 3 SPECIFICATIONS i

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t f re f t tr. cornli gon ro t o f t.iAt t o+3 i.

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Care Montturing 3.

Core Monitoring 7tior to nektng any alterations 1.

')nr isy; enre altera t ion., except to the core the 53M's shall be

.I s in 1.10.I)..!,

two SIC 1' n uh.il l functionally tested and checked I.e "pe ratile, in or adjacent to any f or neut ron response. There-epia.t r a n t s.here f uel or control after, while reqJired to be r eul. a r e in i ni; nov est. I nr.ut fM1 overebis, the SA>4's will be to be con.sidered operable' the thecked delly for toepones except f ol lowi nn *. hall he sa t isf ied:

as specified in 3.10.B.1.b.2.

a.

The S101 nha l l b e i nse r t eil t o the ni.smal operatinn level.

(ll-e of,pec tra l moveabic.

.hnik i vy; t y pe det ec t ors thiring insIial fuel lo.aling anil rninr cure al t er at ion 4 in place M norrtil detertnrs is per-nissible as l o... as the detectot is runnected ta the normal Sict rirenia.)

1.1 The Siul shall have a ntniniua of I rin with all roJs fully

'in.1ted in the rere, if one ci noe. fuel asstmblic.. ate in the core, or e

b.2 During a full core reload where both irradiated and fresh fuel is being loaded.

SRM's (FLC's) may have a count rate of <3 cps g

provided that the SRM's are response checked at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> with a neutron source until >3 cps can be maintained, and provided also that the core is loaded in a spiral sequence only, or 336 O

E-LIMITING CONDITIONS FOR OPERATION.

SURVEILLANCE REQUIREMENTS 3.10.B.

b.3 During a full core reload ubere both irradiated and fresh fuel are being loaded, four (4) irradi-ated ruoi assemblies will be placed adjacent to each SFM to establish a count rate of >3 cps, provided each SRM is functionally tested prior to aojacent fuel leading, a neutron -

response is observed as the adjacent fuel is leaded, and the core is loaded in a spiral cequence only af ter j

tl.e SEM adjacent fuel leading.

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pr uv a de.n pg t en t a y a o.st:t iv 1I y cuntrnI tog t he' I 19 1

.s s s u embl i ers

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in eno cell.n sun H:L a ts d witte thJe coasts ol t od.

Tenne, tonov.el of an entace cal 1 (i uel annemblier pluu cont eci s te l) tv io tt o in i loser react tvaty gotenti sk of t ht' core.

1hp r equ t r ement s f or 'iltM ope r. stat lt ty J ar ing thene core alterationa assures sutCicient core monitor 1r.o.

P E F ER ENC ES t.

Retaelang interlocks (BFNP FSAR Subsection 7.6) 8.

Core Monitoring The SRM's are provided to monitor the core during periods of sta' tion shutdown and to guide the operator during refueling operationta and station startup.

Requiring two operable SRM's in or adjacent to any core quadrant where fuel or control rods are b.*ing moved assut es adequ.ste snonitoring of that quadrant dur teso nuch a l tera t ionn.

The requitament of 3 counts p-r tecond ierovides antaurance that neutt ori flux is tio n net monitornd anl irmur es that startup to conducted only if the source range Llux level La above the minimum assumed in the control rod drop accident.

During a full core reload Srdi/FLC (Fuel Loading Chamber) operability will be verified using a portable external source at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> until sufficient fuel has been loaded to maintain 3 cps. A large number of fuel assemblies will not be required to maintain 3 cps.

This increased surveillance rate assures proper detector operability until that time.

During a full core reload, irradiated fuel may be placed adjacent to each SRM to maintain a count rate >3 cps. Four (4) irradiated fuel assemblies will be placed in the four adjacent fuel locations to each SRM to establish the >3 cps count rate. The response of each SRM to the adjacent fuel loading will demonstrate neutron response. Each SRM will be functionally tested prior to loading the adjacent fuel assemblies. This precludes the use of FLC's as mandatory for a full core reload.

l'nder t he special condition of ter.ovin;; the full core with all control ie.li inserted and elettrically disarmed, it is permissible to allow SU't ccunt rate to decrease below 3 eps. All fuel : oves durinC core ualoading will recuce reactivity.

It is expected that the SFdt's util drep.bclou 3 cps hefore all of the fuel is unloaded.

Since there will be no reactivity cdditions during this period. the low number of ccunts vill not present a hnard, t.~ hen all of the

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inct han 1cen re -oved tc the

t. pent fact stcr...-c p"olc SR*I's'will no longer be requated.

Ncqu a r ity; t !..: $"'l's to be functionally tested prior to fuci rencval assures that tac S:':l'a uill be operabic at the start of fuel ter. oval, lhe daily response check cf the SKII's ensures their centinued operability until the ceant rato diminishes cue to fuct remo.a1.

Control rods in cells froa which all fuel has been rcrtoned rna; t e arred cicetrically and acved far maintenan:c purp:ses d.i r i n e, full core rcroval 1.covid d all rods that control fuci a:e fully inserted and c1ccerically disarmed.

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ENCLOSURE 2 DESCRIPTION OF CHANGES AND JUSTIFICATION TVA BFNP TS 193 The proposed revision will provide means of performing a full core reload with the sole use of the source range monitors (SRMs) for neutron detection. Four irradiated fuel assemblies will be loaded adjacent to the four SRM detectors. This will provide a minimum of 3 cps to verify neutron response and SRM operability. Reloading will proceed as normal starting at the center of the core and spiraling out::ard until the core is completely loaded. If fresh fuel is required to be adjacent to an SRM, the irradiated fuel previously loaded will be removed and the fresh fuel loaded in its place when fuel loading has proceeded to that point..

By using this procedure, critical path time will be reduced by reducing the number of crane operations over the vessel. This will reduce the probability of dropping loose objects into the vessel; thereby increasing the margin of' safety.

This extends the scope of a revision that was made to Browns Ferry technical specifications for units 1, 2, and 3 in amendment Nos. 53, 48, and 25 respectively. The Safety Evaluation Report supporting that amendment is applicable to the proposed revision as discussed below with differences as stated. The proposed amendment is bounded by that SER.

SER S:ection 2.0, " Discussion"

• Section 3.10.B.1.b.2 of Browns Ferry technical specification allows the count rate to drop below 3 cps when reloading the entire core if it is done in a spiral sequence only. The only provision is that the SRMs (FLCs) must be checked for operability every eight hours by the use of a neutron Thus, refueling operations can be accomplished by the method above source.

which has operational inconveniences. The proposed amendment allows the use of irradiated fuel loaded around the SRM as an alternative to source checking.

SER, Section 3 1, " Minimum Flux in the Core"

• The core must have a minimum neutron flux when fuel is being loaded. The j

minimum flux in the core will be provided by the irradiated fuel being j

loaded and by four irradiated fuel assemblies located adjacent to each a

SRM. The proposed amendment does not affect this section.

i SER, Section 3.2, "SRM Operability"

• The appropriate number of SRMs (FLCs) must be operable during core i

alteration. Four irradiated fuel assemblies located around each SRM will continuously provide a minimum countrate of 3 cps; thereby assuring SRM operability with a higher degree of certainty than considered in this section.

• SER sections referenced are from the SER accompanying license amendments issued October 11, 1979, Nos. 53, 48, and 25 to license Nos. DPR-33, 52, and 68, respectively.

, SER. Section 3.3. " Flux Attentatior:"

As described in the SER,16 or more fuel assemblies must be loaded together before criticality is posible. In spiral loading sequences, an array containing four or more control cells will be at most two control cells away from an SRM. With the proposed amendment, this will remain true except that there will be one additional fuel assembly located adjacent to the SRM in the direct path of the center of the core. The additional fuel assembly will not result in additional flux attenuation because it is a multiplying medium. Thus, the ability of the SRMs (FLCs) to monitor core reactivity will equal or exceed that evaluated in the SER. Sufficient monitoring of an approach to criticality will be provided in the proposed configuration.

Safety Analysis Loading irradiated fuel adjace'nt to each SRM (4 assemblies per each SRM) doe = not pose a rafety degradation. All control rods will be completely inserted. The SRM's will be functionally checked before loading the first fuel assembly adjacent to each SRM. The neutron response will be observed as the irradiated fuel assemblies are loaded adjacent to each 1

SRM. A signal-to-noise ratio > 3:1 and >3 ops count rate will be verified upon the completion of loading four (4) irradiated fuel assemblies for each SRM. The General Electric Fuel Relcad Analysis has been demonstrated to be accurate and reliable so that no considerations for criticality around each SRM are necessary. The fuel loading will continue normally in a spiral sequence from the center cell outward until the entire core is loaded. Should an irradiated fuel assembly be placed adjacent to a SRM where a fresh fuel assembly is scheduled to be loaded to attasin the ;>3 cps, then this irradiated fuel assembly will be replaced with the fresh fuel assembly when fuel loading has advanced to that fuel location. Similar technical specifications have been approved for Standardized Technical Specification BWR 4's.

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ENCLOSURE 3 SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION TVA BFNP TS 1983 1.

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

No. This does not increase the chance of a fuel loading error or degrade core monitoring capability during fuel reloading. This will result in a decrease in probability of an accident since the FLC's require additional handling and surveillance.

2.

Does the proposed amendment create the probability of a new or different kind of accident from any accident previously evaluated?

No. There is no new or different accident scenario created that exceeds the previously bounded analysis for core monitoring during refueling. The SRM's used are decigned for core monitoring during refueling.

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

No.

Rather by using the SRM's for core monitoring of the complete reloading, over the FLC's for the initial phase, the margin of safety is increased. The FLC's require additional handling and surveillance which the SRM's do not.

,