HL-1619, Application for Amends to Licenses DPR-57 & NPF-5,changing Tech Specs to Eliminate Rod Sequence Control Sys to Make Unit 1 Specs Consistent W/Unit 2 Specs & to Correct Typos & Clarify Bases

Application for Amends to Licenses DPR-57 & NPF-5,changing Tech Specs to Eliminate Rod Sequence Control Sys to Make Unit 1 Specs Consistent W/Unit 2 Specs & to Correct Typos & Clarify Bases

ML20085G079
Person / Time
Site:	Hatch
Issue date:	10/14/1991
From:	Beckham J GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20085G081	List: HL-1619, Application for Amends to Licenses DPR-57 & NPF-5,changing Tech Specs to Eliminate Rod Sequence Control Sys to Make Unit 1 Specs Consistent W/Unit 2 Specs & to Correct Typos & Clarify Bases ML20085G083
References
HL-1619, NUDOCS 9110240102
Download: ML20085G079 (11)

Text

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lini;h Ptwe ct HL-1619 001557 w L ; p . 1991 U.S. Nuclear Regulatory Commission A11N: Document Control Room Washington, D.C. 205SS PLANT HATCH - UNITS 1 AND 2 NRC DOCKE15 50-321 AND 50-366 OPERATING LICENSES DPR-57 AND HPF-5 EQUEST TO REVISE TED!tti.CALRfilflLA110M ID_LLIMINA1E 1HE R0D 51QUENCE CON 1ROL SYSTEM Gentlemen:

In accordance with the provisions of 10 CFR 50.90, as required by 10 CfR 50.59(c)(1), Georgia Power Company (GPC) hereby proposes a change to the Plant Hatch Units 1 and 2 lechnical Specifications, Appendix A to Operating Licenses DPR-57 and NPT-5.

The proposed change involves changes to the Plant Hatch Units 1 and 2 Technical Specifications for the elimination of the Rod Sequence Control System (RSCS). The changes will make the Unit 1 Rod Worth Minimizer specification consistent with the Unit 2 specification. Additionally, typographical errors are corrected and clarifications to the Bases are made.

Specifically, the proposed Technical Specifications change will allow the removal of the RSCS and enforce Banked Position Withdrawal Sequence (BPWS) with the Rod Worth Minimizer during low power operation.

Enclosure 1 provides a detailed description of the proposed change-asd the circumstances necessitating the change request.

Enclosure 2 details the bases for our determination that the proposed change does not involve a significant hazards consideration.

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Geol);ia Power JL.

U.S. Nuclear Regulatory Comission  !

october 14, 1991 Page Two Enclosure 3 pro; ides page change instructions for incorporating the

)roposed change. The proposed changed Technical Specifications pages for Jnits 1 and 2 follow Enclosure 3. The markup of the proposed change is also included.

To allow time for procedure revisiens and orderly incorporation into copies of the Technical Specifications, GPC requests the proposed amendment, once approved by the NRC, be issued with an effective date to o be no later than 60 days from the date of issuance of the amendment.

In accordance with the requirements of 10 CFR 50.91, the designated state official will be sent a copy of this letter and all applicable enclosures.

Mr. J. T. Beckham, Jr. states that he is duly authorized to execute this oath on behalf of Georgia Power Company, and to the best of his knowledge and belief, the facts set forth in this letter are true.

GEORGIA POWER COMPANY By: -

's~

. T Beckham, Jr.

Sworntoandsubscribedbeforemethis_//Midayof Lisle-Lo 1991.

]YAa udi est{^

Notary Pii ic gneowcmWWWfA RU OCV/cr 001557

Enclosures:

1. Basis for Change Request

2. 10 CFR 50.92 Evaluation

3. Page Change Instructions cc: (See next page.)

mm

Geolgiit l'0Wer U. S. Nuclear Regulatory Congnission October 14 1991 Page Three cc: Storcia Power Comp 1rty Mr. H. L. Sumner, General Manager - Nuclear Plant NORMS U.S. Nattgr_Ecgulatory Commissignuyashinaton. D.C2 Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Regulatory CommisMon. Reaion 11 Mr. S. D. Ebneter. Regional Administrator Mr. L. D. Wert. Senior Resident inspector - Hatch EUL11.pLEtoroia Mr. J. D. Tanner, Commissioner - Department of Natural Resources HL-1619 001557 1

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ENCLOSURE 1 PLANT HATCH - UNITS 1 AND 2 NRC DOCKETS 50-321 AND 50-366 OPERATING LICENSES DPR-57 AND NPF-5 REQRSLILREHE_lECllN LCALJfLC 1f1CMLQNS lq_1LUiWATE THE RQLS1QUfELCONTROL SY.51M Mils FOR CHANGE REQKH PROP 0][D CHAT 1K:

This proposed change will:

1) Delete the requirements for the Red Sequence Control System (RSCS) from the Edwin 1. Hatch Units 1 and 2 Technical Specifications. Banked Position Withdrawal Sequence (BPWS) rod patterns at low powers will be enforced by the Rod Worth Minimizer (RWM). New operational constraints will be placed on the RWM.

2) Revise the Unit 1 Rod Worth Minimizer lechnical Specifications to match the Unit 2 specification.

3) Make administrative changes associated with the two changes above.

4) Correct typographical errors and add clarifications to the Bases.

BASIS FOR PROP 0.jfD CHANE:

At low powers, the Rod Sequence Control System (RSCS) restricts rod movement through the use of rod select, insert, and withdrawal blocks to minimize the individual worth of control rods to lessen the consequences of a postulated Rod Drop Accident (RDA). The RSCS is a hard-wired (as opposed to the RWM which is computer controlled), redundant backup to the Rod Worth Minimizer, it is independent of the RWM in terms of inputs and outputs, but the two systems are compatible. The RSCS is designed to monitor and block control rod selection, withdrawal, and insertion actions, and thus assist in preventing significant control rod pattern errors which could lead to a control rod with a large reactivity worth A significant pattern error is one of several abnormal events all of which must occur to have an RDA which might exceed the fuel enthalpy limit criterion set for the event.

The RSCS was designed only for mitigation of the RDA and is required to be active only during low power operation (currently less than 10% of rated thermal power) when an RDA might be significant. It provides rod blocks on detection of a pattern error, it does not prevent an RDA. A similar pattern control function is performed by the RWM, a computer controlled system.

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O ENCLOSURE 1 (Continued)

EDUESLILB ERSLIICliN I.CALSEEC I EICAHQMS IQ_1 LIB 18 ALE _UiE R00 SEQKNGLC.QMIML 5Y$ TEM in supp0-t of Amendment 17 of General Electric To)ical Report NEDE-240ll- P- A, " Gent .1 Electric Standard Application for teactor fuel,"

the MC issued a Safety Evaluation Report, dated December 27, 1987, approving (1) elimination of the RSCS while retaining the RWM to ,. ovide backup to the operator fm control rod pattern control and (2) lowering the low power setpoint for tu RWH from 20% rated thermal power (RTP) to 10% of RTP. The change request for the Plant Hatch Technical Specifications is consistent with the guidelines set forth in the NRC's SER. (The NRC has already approved reduction of the low power setpoint from 20% to 10% RTP for both ilatch Units 1 and 2.)

As o'iscussed above, the RSCS is a redundant backu) to the RWM. Also, the RWM verifies compliance with Banked Position Witidrawal Sequence (BPWS) which prevents the RDA from exceeding the 200 cal /gm fuel enthalpy criterion. When the RWM is operable, the RSCS is not needed since the RWM prevents control rod pattern errors. In the event the RWM is out of service, after the withdrawal of the first 12 control rods, the proposed Technical Specifications require that control rod movement and compliance with the prescribed BPWS control rod pattern be verified by a second licensed operator or technically qualified member of the plant technical staff. The verification process is controlled procedurally to ensure a high quality, independent rev'ew of control rod movement, in addition, to further minimize control rod movement at low power with the RWM out of l service, the proposed Technical Specifications will permit only one startup per unit per calendar year with the RWH out of service prior to or during the withdrawal of the first twelve control rods. These measures, taken together, demonstrate consistency and applicability to those conclusions

-reached in the NRC's SER for GESTAR-il - Amendment 17, and will prevent significant control rod pattern errors which could lead to a control rod with a large reactivity worth.

The RWM surveillance requirements require a planned entry into the Startup and Hot Standby Mode in order to demonstrate that the rod select error and rod block functions are operational. This test will be performed for the first rod selected during a startup.-

A proper (BPWS) control rod sequence must be loaded into the RWM in order for it to perform its intended function. Once that input has been verified, the RWM will enforce those prescribed rod moves during all subsequent startups and shutdowns; therefore, it is sufficient to require

. verification of the sequence only once - not every time RWM is used.

During those occasions when it is desirable to rapidly reduce power below the RWM low power setpoint, having to verify BPWS rod patterns in the RWM '

would be a great hinderance.

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ENCLOSURE 1 (Continued)

RE0VESL103EYI S LIIC11HICALSP.ECI EICMIONS IQ_LLIMINATE THLRQD_51QVERQLCQRlBQL1151M With the RWM system bypassed, the function of the RWM (i.e., rod pattern control) will be fulfilled by a second licensed operator or other qualified member of the )lant technical staff who will vefify the rod moves. NRC studies have slown that the probabiliy of an RDA exceeding the 280 cal /gm enthalpy limit is approximately 10-l(- events / reactor year with na rod pattern controls (letter and enclosure from B. C. Rusche (NRR) to R. Fraley

{ACRS) dated June 1, 1976,

• Generic item 11 A-2 Control Rod Drop Accident WRs)").

This change also allows bypassing RWH for special testing. This is necessary to perform special tests (required by other Technical Specification requirements), such as scram time testing and shutdown margin testing. This does not represent any additional bypassing of rod pattern controls than already exists under the present Technical Specifications.

Section 3.3.B.1 of the Unit 1 Technical Specifications referred to the incorrect surveillance requirement. This change will refer to the shutdown margin requirement in 4.3.A, not 4.3.B.

The Unit 1 Bases section 3.3.G.1 incorrectly stated that the RWM minimizes the probability, instead of the consequences, of an RDA. This statement is being deleted to be consistent with the RWM design basis.

This change also explicitly identifies BPWS as the correct rod pattern sequence that is to be loaded into the RWM and that tlPWS is only required below 10% of R1 P. Above that power level, BPWS rod patterns are not required to mitigate the consequences of an RDA; therefore, they do not have to be input into the RWM.

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ENCLOSURE 2 1 i

PLAN 1 HATCH - UNITS 1 AND 2 NRC DOCKETS 50-321 AND 60-366  :

OPERATING LICENSE $ DPR-57 AND WPF-5 i REQUELL10_REYllLIECHNICAkitEECIIICATIONS IllullMalL31LB9DlQV1RCE_C9NIROL SMlW j

-10 CFR 50 J2JVALUAT10N l

The Commission has provided standards in 10 CfR 50.92(c) for determining.

whether a significant hazards consideration exists. A proposed amendment i to an operating license for a facility involves no significant hazards '

ccnsMeration if operation of the facility in accordance with the )roposed amendment would nott (1) involve a significant increase in the proaability

• or consequences of an accident previously evaluated, (2) create the possibility of a new or--different kind of accident from any accident 5 previously evalnated, or (3) involve a significant reduction in a margin nf safety. Georgia Power Company has reviewed this proposed license amendment ,

request and determined that its adoption would not involve a significant hazards consideration. The bases for this determination are as follows:

Basis for Proposed No Sionificant Figurds Considention Determination:  ;

The change does not involve a'significant hazards consideration for the following reasons:  ;

1. The _3roposed amendment does not involve a significant_ increase in the i

.proba)ility or consequences of an accident previously evaluated,

a. The -Rod Sequence Control System (RSCS) and Rod Worth Minimizer ,

'(RWM) are separate systems and are not required for, nor do they- l support, the proper operation of any other system, llence, deleting <

the RSCS has no significant effect _on the probability of failure of equipment in other systems or within the RWM.-

The probability of occurrence of an accident is not significantly affected by this change. These changes could only affect the consequences of--the rod drop accident. (RDA), since the probability of an RDA_is dependent _only on the control rod drive system and-mechanisms.themselves,'and not in any way on'the RSCS or RWH. ,

The consequences of an.RDA as evaluated in the Hatch Units 1 and 2 fSARs will not be significantly effected by these changes. '

Dorovements in the RDA analysis methods (e.g., BNL-NUREG 28109,

'T wrmal liydraulic Effects on Control Rod Drop Accident in a BWR "

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i ENCLOSURE 2 (Continued)

REQV E 5L103EY l S L_IECHN IC AL5fTCI El tal10NS 10lLMIMIUlill0RJLQMIEUQNIMLRilEli D u ber 1980) indicated that the peak fuel enthalples resulting from an RDA are significantly lower than previously determined by less refined methodologies. Therefore, the NRC has agreed that BPWS rod pattern restrictions are sufficient to limit the peak fuel enthalpy to less than 280 cal /gm during an RDA. This ensures the radiological consequences will not exceed those described in the FSARs.

The RSCS is a redundant backup to the RWM. When the RWM is operable, the RSCS is not needed since the RWM prevents deviation from BpW3 patterns. In the event the RWM is out of service, after the withdrawcl of the first 12 control rods, the proposed .

Technical Specifications require that control rod movement and compliance with the prescribed BpWS control rod pattern be verified by a second licensed operator or qualified men,ber of the plant technical staff. The verification process is controlled procedurally to ensure a high quality, independent review of control rod movement. In addition, to further minimize control rod movement at low power with the RWM out of service, the proposed Technical Specifications will permit only one startup per unit per calenAr year with the RWM out of service prior to or during W eithdrawal of the first 12 control rods. These measures, taken together, demonstrate consistency and applicability to those conclusions reached in the NRC's SER for GESTAR-ll Amendment 17, and substantiate the co1clusion that there will be no significant increase in the consequences of an RDA as evaluated in the FSAR as a result of eliminating the RSCS.

b. Entry into the startup mode to demonstrate RWM operability will be performed in accordance with approved procedures. Normally, RWM will be operable and the selection of an erroneous rod, as well as its withdrawal, will be blocked by RWM. If RWM is inoperable,

k. thus allowing the selection of an erroneous rod, control room 4 indications will alert the operator that the potential exists to d withdraw the wrong rod. Should the o>erator inadvertently withdraw the wrong rod, and should tie rod " drop", the consequences would be bounded by the existing rod drop accidcnt analysis. Note that this specification already exists in the Unit 2 specification. The probability of a rod drop is unaffected by this change since the assumptiona contained in the original analysis are unchanged (i.e., the rod is fully inserted in the core, becomes uncoupled, the drive is withdrawn and the rod subsequently drops).

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l$ g ENCLOSURE 2 (Continued)=

1 . MQEST TO REVISC TECtlMLCAL SPECIFICATJMS

' ^

'10 ELIMINATE THE ROD 3500ENCE CONTROL SYSTER 9

If 4

The current Unit 2 lechnical Specifications surveillance for RWM requires the BPHS-input be verified only once citer a sequence is '

-loaded into.the RWM. Thereafter, the RWM enforces those BPWS rod -

~ '

-patterns. -Additional restrictions, such as those in the-current-

~

m F ' Unit 1. Technical Specifications, are not necessary to ensure BPWS is- correctly inpu' ' to the RWM, since it will not be altered J: ., . unles s intention- done- so by p1*-t personnel. Therefoi ,

relaxing-_the Un- surveillance requt ements to be the same as Unit- 2 does no, Increase the probability- or consequences of_- an -

accident.- -

Bypassing the RWM is necessary to allow the performance of special tests required _ by other Technical Specification requirements.

.These tests include scram -time testing and shutdown margin

. testing- . This change does. not represent any adriittonal bypassing- <

of rod pattern controls than already exists under the present Technical-; Specifications. Neither does it add any new testing requirements, it merely transfers-the special-test exemptions from the rod pattern. control system being deleted (RSCS), to the one-L ' remaining (RWM). Also, as ngntioned earlier, the probability of- a control rod drop -accident. occurring is extremely -low.

-approximately (1012 : events- per reactor year); it is_ thus t . acceptable to bypass : the rod pattern controls for a relatively

-short period of time to perform these tests.

. c .- _ The: proposed administrative changes: and the correction - of

- typographical errors and statements do not-. result in-modifications

.'of-- plant components:or systems nor do they result in changos-in .

plant operation.~ Therefore, there is no significant it.s %se in-

.the probability or consequences of an accident previously_

. evaluated due to_this change. ,

4

2. The ' proposed amendment:does -not create _the possibility of a new or different kind of accident from any accident previously evaluated.-

la. Operation of tne RSCS and RWM cannot cause or prevent an accident.

These systems function to' minimize the consequences of an RDA.

e These events- are already evaluated in the FSARs, and the effect of this proposed change on the analyses is discussed in Item 1 above.

L: Elimination of the RSCS and the changes to the Unit 1 RWH

-specification will have no impact on the operation of any other p E2-3

ENCLOSURE 2 (Continued)

K@EST TO REYMLl[CILEGAL SPECIE 1CALLDES TO ELIMINATE TBE R00 SE0VENCE CONTROL Sf.5,lEj systems, and therefore would not contribute to a malfunction in any other equipment nor create the possibility for any accident which has not c1 ready been evaluated.

b. Proposed administrative changes, and the correction of typograhical errors and statements do not result in modifications of plant components nor do they result in changes in plant operation. These changes, therefore, do not create the possibility of a new rir different k.nd of accident than previously

-evaluated.

3. The' proposed amendment does not involve a significant reduction in the margin of safety.

Elimination of the RSCS will not result in a significant reduction in the margin of safety for the following reasons:

-a. i) An NRC probability study (letter and enclosure from B. C.

Rusche, NRR, to R. Fraley, ACRS, dated June 1, 197f,

" Generic Item IIA-2 Control Rod Drop Accident (BWRs)") has determined that the probability of an RDA resulting in unacceptable consequences was so small that backfit of the RSCS was not needed.

ii) The RSCS is a redundant backup to the.RWM. Eliminating the RSCS does not eliminate the control rod pattern monitoring function performed by the RWM. Furthermore, to ensure that the RWM-will be in service when requi' red, the proposed RWM Technical Specification allows only one startup per unit per calendar year with the RWM out of service prior to or during the withdrawal of the first 12 control rods. If the RWM is out of service balow 10% of rated thermal power, control rod movement and compliance with prescribed BPWS control rod patterns will be verified by a second licensed operator or technically qualified member of the plant technical staff.

This situation is controlled by a procedure which specifically requires the following:

1) Plant Management approval (Superintendent of Shift or higher) is required in order for the operator to bypass the inoperable RWM.

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V ENCLOSURE 2_(Continued) _

-REQUEST TO REVi1E TECHNICAL SPECIFICATIONL o 'TO ELIMINATE THE-ROD SEQUENCE CONTROL S*(STDl.  !

!2)= A iecond operator or technically qualified plant staff- ,

member,-- with r. oder duties, is. required to verify the

~

first operator's actions while the first operator is performing rod movements.  !

3)1 The-startup and-shutdown sequences with their-respective, signoff sheets are provided to the second operator for:

verification of each step and rod movement made by the  :

first operator, a~

4) The startup -and shutdown sequences follow the same control rod patterns that the RWM enforces if it were ,

not bypassed. -

-GE has provided technical justification for the proposed changes in the Topical. Report NEDE-240ll-P-A~ and associated references

- which ; justify the acceptability of the - proposed change. The NRC

-has reviewed and . accepted -the GE analysis and provided

. guidelines for ' licensees to . follow when - requesting .the changes proposed in NEDE-240ll-P-A and approved in the NRC's SER issued December 27, 1987,' to_ J. S._ Charnley of General Electric. The proposed: change is consistent with those. approved-in=the.NRC's SER  :

and the guidelines -set _forth therein.. Therefore,- there is no significant reduction in-a margin of. safety. t The-changes being made to'make the Unit- I Technical Specifications consis ent with the Unit 2 Technical Specifications do not rede the hk. gin of-safety since the affecteo plant- systems are the x and the margins of_ safety are identical forf the two units.

b.- The proposed administrative changes and the correction 7f typographical errors and statements do -not result in modifications of plant components or-systems nor.do they emult in changes in plant operation. . Thus, this change. does not resul t- in _a significant reduction in the' margin of safety.

SUMMARY

-GPC has concluded these changes do_ not significantly increase the probability or consequences of an ac:ident previously evaluated, create the

-possibility- of1_a new or different kind of accident than previously evaluated, or significantly reduce the margin of safety.

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