ML20137B442

Environ Assessment & Finding of No Significant Impact Supporting Amend to License DPR-65,authorizing Increase of Spent Fuel Pool Storage Capacity

ML20137B442
Person / Time
Site:	Millstone
Issue date:	12/16/1985
From:	Thadani A Office of Nuclear Reactor Regulation
To:
Shared Package
ML20137B427	List: ML20137B423 ML20137B432 ML20137B442
References
TASK-2.E.4.2, TASK-TM TAC-44864, NUDOCS 8601150343
Download: ML20137B442 (8)

Text

!

, 'g

• UNITED STATES

[ o NUCLEAR REGULATORY COMMISSION l

, _a I wAsHmoTom, p. c. sosas

+

k..... ,

ENVIRONMENTAL ASSESSMEN7  :

I BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO EXPANSION OF THE SPENT FUEL POOL NORTHEAST NUCLEAR ENERGY COMPANY, ET AL. ,

MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2 l DOCKET NO. 50-336 ENVIRONMENTAL ASSESSMENT 1: Identification of Proposed Action:

1 The amendment would permit the increase in the licensed storage capacity l from 667 spent fuel assemblies to 1112 spent fuel assemblies for the l Millstone Unit 2 spent fuel pool. This would extend the full core

• j discharge capability for Unit 2 from the year 1985 to the year 1993.

The Need for the Proposed Action i Commercial reprocessing of spent fuel has not developed as had been >

originally anticipated. In 1975, the Nuclear Regulatory Comission directed the staff to prepare a Generic Environmental Impact Statement (GEIS, the -

! Statement) on spent fuel storage. The Commission directed the staff to .

analyze alternatives for the handling and storage of spent light water i . power reactor fuel with particular emphasis on developing long range i policy. The Statement was to consider alternative methods of spent fuel

storage as well as the possible restriction or termination of the l generation of spent fuel through nuclear power plant shutdown.

A Final Generic Environmental Impact Statement on Handling and Storage of I Spent Light Water Power Reactor Fuel (NUREG-0575), Volumes 1-3 (the FGEIS) was issued by the NRC in August 1979. In the FGEIS, consistent with long range policy, the storage of spent fuel is considered to be interim storage i to be used until the issue of permanent disposal is resolved and implemented.

One spent fuel storage alternative considered in detail in the FGEIS is the expansion of onsite fuel storage capacity by modification of the existing i spent fuel pools. Applications for approximately 116 spent fuel pool capacity increases have been received and 111 have been approved. The remaining ones are still under review. The finding in each case has been j that the environmental impact of such increased storage capacity is neg11ble.

However, since there are variations in storage designs and limitations i

caused by the spent fuel already stored in some of the pools, the FGEIS reconmends that licensing reviews be done on a case-by-case basis to resolva pirat-specific concerns.

~

9601150343 851216  ;

PDR ADOCK 05000336 p PDR

t Environmental Impacts of'the Proposed Action A. Radiation Exposure l

Occupational Exposure '

4 The staff has reviewed the licensee's plan for reracking and modifying the

! spent fuel pool (SFP) with respect to occupational radiation exposure. The i licensee will use divers to disconnect the old racks and components. <

j Because of the exposure to the divers and increased exposure to other ,

4 personnel, the occupational exposure commitment from the rerack activities will be about 3-8 man-reri. The staff considers this to be a reasonable -

estimate. This estimate represents a small fraction of the total 500  ;

man-rem burden from occupational exposure at the plant.

The licensee plans to take the following actions to keep occupational i

radiation exposure to as low as is reasonably achievable (ALARA). These i

! actions include: (a) vacuum cleaning of SFP floors; (b) maximum water  ;

i shielding to reduce dose rates to divers; (c) underwater radiation surveys; t i (d) calibrated alarming dosimeters and personnel monitoring dosimeters for divers; (e) hydrolasing and cleaning of old spent fuel racks; (f) the use  !

of remote operations for rack removal and replacement operations; and (g)  ;

visible work zone barriers for diving operations seven (7) feet from the i nearest filled spent fuel rack. Based on the above actions, the staff l concludes that SFP modification exposure to workers is expected to be ALARA ,

j and is therefore acceptable, j t

The licensee estimates that the additional occupational radiation exposure

, for operation of the reracked pool is less than 1 man-rem /yr. The licensee  !

j also has provided a description of contained and airborne radioactivity -

~

sources related to the SFP water and which may become airborne as a result i of failed fuel and evaporation. The staff has reviewed these source terms  !

and finds them acceptable. The additional dose is less than 0.2% of the t

average annual occupational dose of 500 person-rems for all plant operations  !

i at Millstone Unit 2. The small increase in radiation dose should not >

1 affect the licensee's ability to maintain individual occupational doses to i

, ALARA levels and within the limits of 10 CFR Part 20. Therefore, the staff l l concludes that storing additional fuel in the SFP will not result in any l

significant increase in doses received by workers.  !

Public Exposure i The staff has completed an analysis estimating the radiological impact on  !

the public from the proposed SFP modification. Major sources of radioactivity l i and principal environmental pathways were considered in preparing this analysis.  !

i The staff has estimated the doses to individual members of the public as  !

c well as the population as a whole in the area surrounding Millstone Unit 2 by j conservatively assuming a release of 125 Ci of Kr-85 due to the proposed increased storage of spent fuel assemblies and using the calculational  !

methods presented in Regulatory Guide 1.109. Krypton-85 is the principal l l

i

___._..,. _ ,.-_ .._._ - --_,_._ _ ,.-- __.__..._._ _ _.. _.____,.~ ._ _ _ -._ -.- _ .__. ___,, ,,

l

. I

• ~

source of radiation exposure to individual members of the general public.

The staff estimated the total body and organ doses for the direct radiation '

exposure pathway from the Kr-85 plume shine for individual members of the j general public of all ages at the worst site boundary location, 0.5 miles northeast of the plant, resulting from the assumed additional release of l I airborne Kr-85. The individal member of the public was conservatively assumed to occupy the site boundary with the worst atmospheric dispersion

, characteristics continuously for a whole year. An atmospheric dispersion

! factor, X/Q of 4 x 10-6 sec/m was used 'In these estimates.

} The additional total body dose that might be received from the assumed

. release of Kr-85 by an individual at the worst site boundary location and  ;

' the estimated dose to the total body of the population within an 80

kilometers radius of the plant is less than 0.1 mrem /yr and 0.1 ,

person-rem /yr respectively. These doses are small compared to the j fluctuations in the annual dose this population receives from exposure to l

background radiation. The population dose due to the SFP modification j represents an increase of less than 0.1 percent of the population dose i

, evaluated in the Final Environmental Statement (FES) for the release of 6 noble gases from the normal operation of Millstone Unit 2. ,

By comparison, every year the sare population of about 3,300,000 persons ,

1 will receive a cumulative total body dose of more than 370,000 person-rems  !

! from natural background radiation of about 0.11 rem per year per person  ;

! (U.S. Environmental Protection Agency, 1972. DRP-SID-72-1, " Natural i Raciation Exposure in the United States," June 1972). Thus, the additional

, total body dose to the population from the SFP modification is estimated to i be less than 0.0001% of the annual dose due to natural background. On this  !'

~

basis, the staff concludes that the doses to individuals in unrestricted i areas and to the population within 80 kilometers due to the assumed l i additional airborne Kr-85 released annually from the SFP modification will i j not be environmentally significant.  !

l i B. Radioactive Wastes l The plant contains radioactive waste treatment systems designed to collect i and process the gaseous, liquid, and solid waste that might contain l

radioactive material. The radioactive waste. treatment systems are I i evaluated in the Final Environmental Statement (FES) dated June 1973. j l There will be no change in the waste treatment systems described in Section '

T.4.2 of the FES because of the proposed SFP rerack.

Radioactive Material Released to the Atmosphere l With respect to releases of gaseous materials to the atmosphere, the only l

! radioactive gas of significance which could be attributable to storing  !

i additional spent fuel assemblies for a longer period of time would be the

noble gas radionuclide Krypton-85 (Kr-85). Experience has demonstrated j

that after spent fuel has decayed 4 to 6 months, there is no longer a i

significant release of fission preducts, including Kr-85, fra

stored spent t

fuel containing cladding defects. To detemine the average annual release

l.  :

1 i

_ _._. _ . _ _ . _ .,._._ _ . _ . _ ._ .. _ . _ . i

F l l o l t -

, l

~

of Kr-85, we assume that all of the Kr-85 released from any defective fuel  !

discharged to the SFP will be released prior to the next refueling.  !

Enlarging the storage capacity of a spent fuel pool has no effect on the calculated average annual quantities of Kr-85 released to the atmosphere each year. There may be some small change in the calculated quantities due to a change in the fuel burnup; this is expected to be a small fraction of the calculated annual quantities. However, for the purpose of estimating i i potential radiation doses to the members of the public due to the proposed (

increased storage of spent fuel assemblies, the staff has conservatively ,

assumed an additional release of 125 C1/ year of Kr-85. j

! Iodine-131 release: from spent fuel assemblies to the SFP water will not be significantly increased because of the expansion of the fuel storage capacity since the Iodine-131 inventory in the fuel will decay to negligible levels between refuelings.

Most of the tritium in the SFP water results from activation of boron and  !

. lithium in the primary coolant and this will not be affected by the  !

j proposed change. A relatively small amount of tritium is contributed I 4 during reactor operation by fissioning of reactor fuel and subsequent i

! diffusion of tritium through the fuel and the fuel cladding. Tritium F

]

release from the fuel essentially occurs while the fuel is hot, that is. l

during operations and, to a limited extent, shortly after shutdown. Thus,- 4

expanding the SFP capacity will not cignificantly increase the tritium 1

activity in the SFP. (

, c

! Storing additional spent fuel assemblies is not expected to increase the i bulk water temperature during normal refuelings above the value used in the i

design analysis. Therefore, it is not expected that there will be any j significant change in the annual release of tritium or iodine as a result  !

j of the proposed modifications from that previously evaluated in the FES.

t Most airborne releases of tritium and iodine result from evaporation of

}

reactor coolant, which contains tritium and iodine in higher concentrations l j than the SFP. Therefore, even if there were a higher evaporation rate from  ;

j the SFP, the increase in tritium and iodine released from the plant, as a i

! result of the increase in stored spent fuel, would be small compared to the j amount normally released from the plant and that which was previously i evaluated in the FES. The SFP exhaust system must be operating and i discharging through both HEPA and charcoal filters whenever spent fuel is i . stored in the SFP and either fuel is being moved or other loads are being L carried over the SFP (TS 3.9.12). In addition, the station Radiological I

Effluent Technical Specifications, which are not being changed by this action, limit the total releases of gaseous activity. ,

Solid Radioactive Wastes j The concentration of radionuclides in the pool water is controlled by the [

SFP cleanup system and by decay of short-lived isotopes. The activity is I highest during refueling operations when reactor coolant water is [

introduced into the pool and decreases as the pool water is processed

~

t through the SFP cleanup system. The increase of radioactivity, if any, due to the proposed modification should be minor because of the capability of l the cleanup system to continuously remove radioactivity in the SFP water to j j acceptable levels.  !

! I

'_-- -_-___ ____ _ ___..__E __ _.___ _.~._-_.._.-__. .- _ _.,__ _ -.-.

+

! The staff does not expect any significant increase in the amount of solid l waste generated from the SFP cleanup systems due to the proposed '

modification. The expected increase in total waste volume shipped from the Millstone Nuclear Power Station, Unit 2 is less than 1% and would not have any significant additional environmental impact. l

If the present spent fuel racks to be removed from the SFP of the Millstone Unit 2 facility are contaminated because of the proposed modification. .

l they may be disposed of as low level solid waste. Averaged over the j '

l lifetime of the station, this would increase the total waste volume shipped from the station by less than 1%. This will not have any significant ,

i additional environmental impact.

1 Radioactive Material Released to Receiving Waters i

There should not be a significant increase in the liquid release of I radionuclides from the plant as a result of the proposed modifications.  !

4 Since the SFP cooling and cleanup systems operate as a closed system, only j water originating from cleanup of SFP floors and resin sluice water need be i considered as potential sources of radioactivity.  !

l It is expected that neither the flow rate nor the radionuclide l 1~ concentration of the floor cleanup water will change as a result of these ,  ;

i modifications. The SFP domineralizer resin removes soluble radioactive  !

l materials from the SFP water. These resins are periodically sluiced with l

! water to the spent resin storage tank. The amount of radioactivity on the ,

l SFP domineralizer resin may increase slightly due to the additional spent  :

fuel in the pool, but the soluble radioactive material should be retained ,

on the resins. Radioactive material that might be transferred from the spent resin to the sluice water will be effectively removed by the liquid j radwaste system. After processing in the liquid radwaste system, the amount  :

of radioactivity released to the environment as a result of the proposed  !

j modification would be negligible. l-Non-Radiological Impact i When licensed in August 1975, the fuel pool rack capacity of Millstone ,

- Unit 2 was 301 spent fuel assemblies or about 1.3 full reactor cores. By l November 1976, the licensee concluded that a capacity expansion of the j spent fuel pool was necessary. An amendment to the operating license was  !

l issued by the NRC on June 30, 1977, allowing re-racking of the spent fuel l

pool to provide the capacity for 667 fuel assemblies. This capacity was  !

adequate for spent fuel discharges plus full core fuel assembly removal l l through 1984. After the Cycle 6 refueling outage in 1985, the spent fuel l pool no longer has full core reserve capacity.  !

i i

The licensee proposes to expand the storage capacity to acconinodate 1112  !

! fuel assemblies using a new design comprised of new high density poisoned j and non-poisoned racks. The new design will consist of one region i containing two 8 x 9 modules and three 8 x 10 modules that would have +

capacity for 384 fuel assemblies of high-enrichment core off-load  :

assemblies. This region is designed to acconsnodate 1.7 full reactor l cores. The second region will be used to store fuel assemblies with 85% ,

I f

r

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

- i of its design burn-up. This region will consist of 14 modules of 4

non-poisoned racks and will accommodate 728 fuel assemblies. The net

c result of increased capacity is that older spent fuel assemblies can be 4 left in storage for a longer time, thus reducing the impacts associated with l handling and transportation to other storage facilities.

l The existing racks will be disposed of through normal industrial channels.

The new racks will be fabricated offsite. Installation is not expected to impact terrestrial resources not previously disturbed during original station construction.

The only non-radiological discharge altered by the spent fuel pool i modification is the waste-heat. Thg maximum heat load for the original

spent fuel pool design is 26.0 x 10 Btu /hr compared to 37.8 Btu /hr for the

expanded design. Maximum heat load would be expected with the entire core of(-loaded. Normal heat load for the new design is predicted to be 15.2 x 10 Btu /hr after normal refueling with the most recent off-loaded fuel i assemblies having decayed for 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br />. The increase in heat load under i.e., entire core off-load) for the maximum, expanded fuel abnormal circumstanceg pool is 9.8 x 10 B (tu/hr, a 35 percent increase above heat

! load for the original design. The calculated igcrease in heat load for normal refueling for the new design is 3.9 x 10 Btu /hr, a 35 percent increase resulting in an increase in spent fuel pool water temperature froni

120'F to 131'F.

The increase in heat discharge due to fuel pool capacity expansion would j cause a negligible temperature increase (0.014*F at normal operating flow

rate of 1220 cfs for Unit 2) in the discharge water temperature of the

. once-through cooling system. No impacts to aquatic biota or water quality '

are anticipated from the additional heat load.

~

The licensee has not proposed any change in the use or discharge of chemicals in conjunction with the fuel pool modifications.

Alternative Use of Resources:

) This action does not involve the use of resources not previously considered in connection with the Nuclear Regulatory Consission's Final Environmental Statement dated June 1973 related to this facility.

Agencies and Persons Consulted:

The NRC staff reviewed the licensee's request and did not consult other agencies or persons.

} BASIS AND CONCLUSION FOR NOT PREPARING AN ENVIRONMENTAL IMPACT STATEMENT

! The staff has reviewed this proposed facility modification relative to the requirements set forth in 10 CFR Part 51. Based on this assessment, the

! staff concludes that there are no significant radiological or l

non-radiological impacts associated with the proposed action and that the l l

i

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

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

. l l

,. issuance of the proposed license amendment will have no significant impact on the quality of the human environment. Therefore, pursuant to 10 CFR 51.31, an environmental impact statement need not be prepared for this action.

Dated at Bethesda, Maryland, this 16th day of December.1985.

FOR TH NUCLEAR RE LATORY C0idISSION fY6.VObv~

l Asho C. Thadani Director PWR roject Directorate #8 Division of PWR Licensing-B 4

e I -

~

I 1

l 1

i

Tj -_-

UNITED STATES

1. pa "'%q'o g NUCLAAR REGULATORY COMMISSION g wAsmNGTON, D.C. 20086 f

- e

• e g4,,,,,jf _.

d January 2

- e w f m ,:190$ m ,

DOCKET No. 50-335 MEMORANDUM FOR: X5MMMMMalEMleUK Rules & Procedures Branch stHEMmWmUUr5HE.MMM.LU Division of Rules & Records

- Office of Adinhistration FROM: Office of Nuclear Reactor Regulation WBB-4000 DivisioneffPWR LicensinggB

SUBJECT:

111LLSTONE NUCLEAR POWER STATIO!!, UNIT NO. 2 One signed original of the Federal Register Notice identified below is enclosed for your transmittal to the Office of the Federal Register for publica' tion. Additional conformed copies ( 6 ) of tiie Notice are enclosed for your use.

C liotice of Receipt of Application for Ctmstruction Permit (s) and Operating License (s).

Notice of Receipt of Partial Applicatir.a for Construction Permit (s) and Facility License (s). Tirne for Submission of Views on Antitrust Matters. , ,

N Notice of Consideration of issuance of Amendment to Facility Operating License.

C Notice of Receipt of Application for Facility License (s); Notice of Availability of Applicant's Environmental Report; and Notice of Cons:deration of issuance of Facility License (s) and Notice of Opportunity for Hearing.

Nctice cf Availability of NRC Draft / Final Environmental Statement. .

Notice of Limited Work Authorization.

O Notice of Availability of Safety Evaluation Report.

C Notice of issuance of Construction Permit (s).

O Notice of issuance of Facility Operating License (s) or Amendment (s).

O Order.

O Exemption.

Notice of Granting of Relief, h Other:. stest;; gf {guj ;;-.3 t3] geegee gnt gna rindinn nf tin Rinnificant Tmnact t

Office of Nuclear Reactor Regulation Division of. PWR LicenMng-B

Enclosure:

As stated \, ,

CC'M/OHC10$mre

-> se...n.st..paoe.. . . . . . . . !. . ." *f" . ' " ."' ". .". .' ... .' .' .."""....".."..... .'""...' .'""....*' ".' '. .* "'."..."."'...'..."' . .

===k . . . . . . . . . . . . . . . . . . . ./ . . . .N. .d..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

- ~

OFFICIAL RECORD COPY A

~

. - - - - . .__ - - - - - - - _ ---- nJ