ML20205R131

Safety Evaluation Supporting Amend 101 to License DPR-63

ML20205R131
Person / Time
Site:	Nine Mile Point
Issue date:	10/31/1988
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML17055E305	List: ML20205R131
References
GL-85-03, GL-85-3, NUDOCS 8811090455
Download: ML20205R131 (4)

Text

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 101 TO FACILITY OPERATING LICENSE NO. DPR-63 ,

t l NIAGAPA MOHAWK POWER CORPORATION NINE MILE POINT NUCLEAR POWER STATION, UNIT NO. 1 DOCKET NO. 50-200 l INTRODUCTION i

in a letter dated March 7.1988, the licensee requested Technical Specifications i Sections 3.1.2 and 4.1.2 be revised for the liquid poison system to incorporate  :

changes reouired by 10 CFR Part 50.67. "Requirements for reduction of risk from  :

anticipated transients without scram (AT*ds) events for light-water-cooled  :

! nuclear power plants." Specifically, the proposed changes would-(1) delete  ;

) Fiqure 3.1.?a; (2) identify the liquid poison system minimum volume requireNnts; i

(3) incorporate the equivalency equation for detkrmining the concentration of .

I sodium pentaborate solution enriched in the boron-10 isotope; (4) revise Figure  !'

j 3.1.2b to allow a lower concentration of sodium pentaborate as a result of

) using the enriched isotope; and (5) revise Technical Specification 4.1.2b to j j incorporate additional surveillance requirements for monitoring the enriched +

! boron-10 isotope concentration. The Pases for Technical Specification Sections  ;

l 3.1.2 and 4.1.? would also be revised to incorporate the equivalency equation  !

. and to remove the reference to the maximum in,iection time and revise the  !

! minimum in,iection time. The deviations from 10 CFR Part 50.6?(c)(4) associated i with the Technical Specification changes are identified in an exemption request i dated September 14, 1988. The discussion of the exemption rtyuest is included as  !

i part of this Safety Evaluation. l t

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EVALVATION l The exemption proposed by the licensee has been reviewed by the staff against i

the requirements of the Anticipated Transient Without Scram (ATWS) rule i

! (10 CFR Part 50.62) and Generic letter No. 85-03 "Clarification of Equivalent i

! Control Capacity for Standby Liouid Control Systems." dated January 28, 1985. -

i The licensee's proposed consideration of the 213-inch diameter vessel size in 6 j detennining an equivalent control capacity will provide a bnron cMtent  !

. ecuivalent in control cacacity to 86 gpm of 13 weight percent sodium  :

! pentaborate for a 251-inch inside diameter vessel. This meets the intent of j 10 CFR Part 50.62 and is, therefore, acceptable. Granting of this Exemption j orovides iustification for certain of the TS changes identified in the  ;

amendment request. j I

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l I The liquid poison system is a backup to the Control Rod Drive System. When a 4 scram signal occurs, the control rods are automatically inserted to bring the reactor to a suberitical condition. In the event the control rods would fail  ;

i to insert, the liquid poison system is designed to in.fect a sufficient quantity of soluble boron to bring the reactor to a hot suberitical condition. The liquid noison system at Nine Mile Point tinit 1 (NMP-1) performs the function of the standby liquid control system (SLCS) required by Paragraph (c)(4) of 10 CFR 50.6? which states, in part: ,

"Each boiling water reactor must have a standby liquid control system

(SLCS) with a minirum ficw capccity and boren content equivalent in control capacity to 86 gallons per minute of 13 weight parcent sodium penta > orate solution."

i Generic letter 85-03, dated January 28, 1985, stated that the equivalent boren '

content could be achieved by increasing the flow rate, or the boron concentrath, i or through boron enrichment. These methods of meeting the requirements of 10 t CFR 50.62 were also evaluated in the staff's review of NEDE-31096-P "Anticipated 1 Transients Without Scran: Ferponse to ATWS Rule 10 CFR 50.62 " (G. Lainas to l

T. Pickens, October 21,1986). The staff's evaluation of NEDE-31096-P also ,

i discussed an equivalency equation which could be used to ensure that the SLCS has a control capacity eouivalent to 86 GPM of 13 weight percent natural sodium  :

4 pentaborate solution.

l In its application dated March 7, 1988, the licensee requested that the Technical l Specifications for NMP-1 be revised to incorporata the following ecuivalency h

equation which was discussed in the sta#f's evaluation.

I O x M251 x Cx E >1 ,

Fi T -~ T3 17"3 -

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whera: 0

• expected Liouid Poison tystem flow rate (30 GPM)

M = mass of water in the re6ctor vessel and recirculation  :

J system at het rated conoitions (501,500 lbs.)

! C = sodium pentaborate soh ; ion concentration, weight percent t 4 E = boron-10 isotope enrichfient (10.8% for natural boron), [

atom percent M251 = mass cf water for 251-inch reference plant (628,300 lbs ,

! The licensee has proposed to meet the eouivalency equation by using appropriate l l combinations of solution concentration and boron-10 enrichment. j

! i The licensee has indicated that the enriched boron would be supplied premixed  ;

! by its vendor. On April 13, 1088 the licensee supplewented its amendnent i application with a letter comitting to revise the applicable site procedures ,

j to require an isoteoic analysis of the enriched sodium pentaborate to be ,

performed by an independent laboratory. In addition, the licersee's amendment  :

} application of Farch 7,198A included surveillance recuirements to verify  !

conformance with the equivalency equation any time boron or water is added or f 1 if the solution tenperature drops below the limits specified by Fiqure 3.1.?b, .

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- and to verify enrichment by analysis once per operating cycle. The staff finds l i

the proposed surveillance requirements and the licensee's comitment to have an l independent verit{ cation to be adequate assurance that the licuid poison system  :

! will meet the requirements of the St.CS required by 10 CFP 50.6?. j With the use of the equivalency equation, the effective rate of boron in.iection

< product of pumping capacity (flow rate), solution l l

concentration, boron (Rintothecorewillbetg1 enrichment,andmixinocapacity. Previously conducted L mixing tests were accepted by the NRC staff and, as a result, boron abing is not '

o a factor in determining equivalency to the ATWS rule. By meeting the equivalency i

equation, the licensee will ensure that sodium pentaborate is iniected at a rate eouivalent to 13 weight percent at 26 GPM. As the rate of infection will be  ;

onverned by the eouivalency equation and boron mixing is not a factor, the minimum and maximum in.iection times need not be reviewed by the staff. Therefore, the deletion of the maximum mixino time and the revision to the minimum mixing time  !

in the Bases is acceptable. l f

Figure 3.1.2a of the Technical Specifications specified the volume-concentration l

- limits of the liquid poison system. This curve is applicable for natural  ;

(unenrichedi boron. These limits will now be determined by the use of the

equivalency equation and therefore, deletion of Figure 3.1.2a of the Technical Specifications is acceptable. l 1 l 1 Fioure 3.1.2b of the Technical Specifications specified the minimum allowable 1

solution temperature 'or a specified weight percent of sodium pentaForate in ,

solution. This curve was being revised to include the lower weight -:rcent o' '

sodium pentaborate allowed by the ecuivalency equation. However, the licensee  !

did not address the potential for freezinq at the lower terperatures (30*F)  !

represented on the new curve, in addition, during a discussion with Mr. Peter j j Francisco of the licensee's staff on June 23 loa 8, Mr. Francisco indicated  :

f that the curve was erroneously shifted in the non-conservative direction.  !

( Pr. Francisco further indicated that operation with the equivalency equation j with the existing Fioure 3.1.2b would be acceptable. The use of the existinq  !

i fioure for the minimum allowable solution temperature would not ha affected by {

the use of the equivalency equation. Therefore, the staff firds the proposed r

! revision to Fiqure 3.1.2b to be unacceptable and the licensee has aareed that "

chance will be deleted from the proposed revision to the Technical Specifications.  !

! This change did rot alter or affect the action noticed or the staff's initial  !

j determination published in the Federal Degister on June 1,1988.

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} On the basis of the above discussion, the staff finds that the licensee's  !

changes to the Technical Specification and the Rases for the liquid poison l 1 system as proposed in fts application of Parch 7, 1988 with the exception as  ;

modified, are acceptable and are consistent with the purpose of 10 CFR Part

1 50.6? for the St.CS. ,

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ENVIRONMENTAL CONSIDEPATION

! This anendment involves a change in the installation or use of the facility l l components located within the restricted areas as defined in 10 CF'l Part 20 and l j changes inspection or surveillance requirerents. The staff has determined that l j this amen &ent involves no sionificant increase in the amounts, and no sicnificant  ;

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4 change in the types, of any effluents that may be released offsite and that there I is no significant increase in individual or cumulative occupational radiation '

exposure. The Comission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public coment on such finding. Accordingly, this 6mendment meets the eligibility ,

criteria for categnrical exclusion set forth in 10 CFR Sec 51.22(c)(9). Pursuant  !

to 10 CFR Sec. 51.22(b) no environmental irrpact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

1 CONCLUSION, On the basis of the above evaluation the staff finds that the licensee's proposed exemption from 10 CFR Part 50.62(c)(4) as requested in the submittal dated Septernber 14, 1988 is acceptable. Thereafter, the licensee shall comply t

with the provisions of such rule or renew its request for exemption.

! We have concluded, based on the considerations discussed above, thn: (1)there !

15 reasonable assurance that the health and safety of the public will not be l' endangered by operation in the proposed manner, r.nd (2) such activities will be conducted in compliance with the Comission's regulations and the issuance .

l of these amendments will r.ot be inimical to the corinon defense and security or 1 to the health and safety of the public.

i i Dated: October 31, 1988 1 PRINCIPAL CONTRIBUTOR:

N haughey 4  :

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