ML20205F126

Environ Assessment & Finding of No Significant Impact Supporting Schedular Exemption from Portion of GDC 4 Requirements of 10CFR50,App a

ML20205F126
Person / Time
Site:	Byron, Braidwood, 05000000
Issue date:	10/21/1985
From:	Novak T Office of Nuclear Reactor Regulation
To:
Shared Package
ML20205E877	List: ML20205E874 ML20205E879 ML20205F119 ML20205F126
References
NUDOCS 8511040493
Download: ML20205F126 (9)

Text

'~ ~

. t ..

1 l

7590-01 UNITED STATES NUCLEAR REGULATORY COMMISSION N COMMONWEALTH EDISON 1 DOCKET NOS.: STN 50-455 -

d STN 50-456 AND STN 50-457 d

3 ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT IMPACT

- The U. S. Nuclear Regulatory Comission (the Commission) is considering j .

issuanceofascitedularexemptionfromaportionoftherequirementsofGeneral Design Criterion 4 (10 CFR 50, Appendix A) to the Commonwealth Edison Company,

{

I (the app'licant) for Byron Station, Unit 2, and Braidwood Station, Units 1 and 2 (thefacilities). Byron Station, Unit 2, is located at the applicant's site in Ogle County, Illinois, and Braidwood Station, Units 1 and 2, is located at the applicant's site in Will County, Illinois.

l .

.. ' ENVIRONMENTAL ASSESSMENT:

Identification of Proposed Action: The schedular exemption would pennit the applicant, for two cycles of operation, to eliminate the dynamic loading effects associated with postulated pipe breaks in the primary coolant system of each of the three facilities on the basis of advanced calculational methods for assuring that piping stresses would not result in rapid piping failure;

~ r-1 1.e., pipe ~ breaks.

8511040493 851028 PDR ADOCK 05000455 A PDR l

• 7590-01 4

Need for Proposed Action: The proposed' schedular exemption is needed in order to pemit the applicant not to install certain protective devices, such as pipe whip restraints and jet shields, in the primary coolant loops of Byron 2 and Braidwood I and 2. Analysis shows that pipe breaks, which these devices are designed to protect against, will not occur. On the other hand the presence of these devices increases inservice inspection time in the containment and

their elimination would tend to lessen the occupational doses to workers and facilitate inservice inspections. General Design Criterion (GDC) 4 requires that structures, systems and components important to safety shall be appropriately I

protected against dynamic effects including the effects of discharging fluids that may result from equipment failures, up to and including a double-ended rupture of the largest pipe in the reactor coolant system (Definition of LOCA).

In recent submittals the applicant has provided infomation to show by advanced j-

~

fracture mechanics techniques that the detection of small flaws by either in-

~

service inspection or leakage monitoring systems is assured long before flaws in the piping materials can grow to critical or unstable sizes which could lead to large break areas such as the double-ended guillotine break or its equivalent.

4 The NRC staff has reviewed and accepted the applicant's conclusion. There-fore, the NRC staff agrees that consideration of the dynamic loading effects associated with postulated double-ended guillotine breaks in the primary pressure coolant loop piping need not be required as a design bashi accident for pipe protective devices and jet shields. Accordingly, the NRC staff agrees that

a schedular partial exemption from CDC 4 is appropriate. -

i i

~

_ __ ._ _ _ . . . . _ _ _ . . a

F .

7590-01 J Environmental Impact of the Proposed Action:- 'The proposed schedular exemption g would not affect the environmental impact of the facilities. No credit is given

$c ,

for the restraints and barriers to be eliminated in calculating accident doses to the environment. While the pipe whip restraints and jet impingement barriers wculd minimize the damage from jet forces and whipping from a broken pipe, the d

calculated limitation on stresses required to support this exemption assures

! that the probability of pipe breaks which could give rise to such forces are extremely small; thus, the pipe whip' restraints and jet shields would have no a

significant effect on overall plant accident risk.

.i The exemption does not othenvise affect radiological plant effluent. Like-wise, -the relief granted does not affect non-radiological plant effluents, and has no other environmental impact. The elimination of the pipe whip restraints

{

and jet impingement shields would tend to lessen the occupational doses to lI workers inside containment. Therefore, the Commission concludes that there 8

are no significant radiological or non-radiological impacts associated with this exemption.

The proposed exemption involves design features located entirely withi*

the restricted area as defined in 10 CFR 20. It does not affect plant non-radioactive effluents and has no other environmental impact. Therefore, the Comission concludes that there are no non-radiological impacts associated

~

with this proposed Exemption.

bb

_~

m. .1 , .,,,.,m m, .m_.. _ - . - - - _ _ _ _ _ _ _ . _ - . . - -

7590-01 l

Since we have concluded that there are no measurable negative environ- ,

mental impacts associated with this exemption, any alternatives would not

- provide any significant additional protection of the env_ironment. The alter-

- native to the exemption would be to require literal compliance with GDC 4.

Alternative Use of Resources: This action does not involve the use of resources not previously considered in the Final Environmental Statements (construction pemit and operating license) for both Byron Station, Units 1 and 2, and

~

Braidwood Station, Units 1 and 2.

t Agencies and Persons Contacted: The NRC staff reviewed ;the applicant's request and applicable documents referenced therein that support this exemption for thefacilithes. The NRC did not consult other agencies or persons.

FINDING OF NO SIGNIFICANT IMPACT The Commission has detemined not to prepare an environmental impact statement for this action. Based upon the environmental assessment, we conclude that this action will not have a significant effect on the quality of the human environment.

For details with respect to this action, see the request for exemption dated September 17, 1984 and additional information provided by the applicant in letters dated June 28, 1985, August 14, 1985 and September 25, 1985. These documents, utilized in the NRC staff's technical evaluation of the exemption request, are available for public inspection at the Connission's Public ea -es * -**"w****w. , , _ w pga e

-W.

• M"* pup P y +* T 1 - T{ *a

• y W ' pg -

- - - ~  : e

m. - . .

. . c l 7590-01

. i Document Room, 1717 H Street, N. W., Washington, D. C., and at the Rockford i

, l' j Public Library, 215 N. Wyman Street, Rockford, Illinois, 61103, and the i .

Wilmington Township Public Library, 202 S. Kankakee Street, Wilmington, Illinois 60481. The staff's technical evaluation of the exemption request will be published with the exemption and will also be available for inspection at all locations listed above.

Dated at Bethesda, Maryland this h h day of C M 985.

s FOR THE NUCLEAR REGULATORY COMMISSION i omas M. Novak, Assistant Director Division of Licensing Office of Nuclear Reactor Regulation A,

1

~ t-a

' =

.{0-46[

DISTRIBUTION:

'($Mf?MR m run ~ aa a L PDR NSIC PRC System LBf1 R/F MRushbrook L01shan JStevens TNovak HThompson/FMiraglia OELD ACRS (16)

JPartlow BGrimes EJordan FCherny RBosnak JKudrick RHouston FCongel-DMuller-RKlecker BDLiaw WJohnston-JKnight

OCT 2 81985 Mr. Dennis L. Farrar On the basis of the staff's evaluation of these submittals the Conmission has granted your excrtption request for periods ending at the completion of the second refueling outage of each of the facilities, pending the outcome of the Commission's ongoing rulemaking on this subiect. The staff has also received your Septem5er 25, 1985 letter requesting amerdrents to the construction per-mits for Byron Station, tinit 2, and Braidwood Station, Units 1 and 2. The exemption grinted will become effective upon the date of issuance. The enclosed exenption is being forwarded to the Office of the Federal Register for publicat'on, accordingly.

Sincerely, S

B. J. Younablood, Chief Licensing Branch No. 1 Division of Licensing

Enclosures:

As stated cc: See next page

• SEE PREVI0ttS PAGE FOR CONCllRRENCES g' LB#1/DL LB#1/DQ LB#1/DL LB#1/DL LB# /DL DELD ti.01shan/mac JSteveq u *MRushbrook 4f*BJYoungblood KJabbour *SHLewis 3o008/16/85 0/ 3 /85- / /85 08/16/85 10/j4/85 08/27/85 to n gid ldE ( A q g/DL

[mTiaw (, .

<ovak , iTnonnson go/ \ /85 7 3( e,85 /g/p[/85 to /g /85

OCT2s geS l Pursuant to 10 CFR 51.31, the Commission has determined that the issuance of the exemption will have no significant impact on the environment (50 FR WMY ).

The exemption will become effective upon date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION Hugh L. Thompson, Jr., Director Division of Licensing Office of Nuclear Reactor Regulation Dated at Bethesda, Maryland this y day of 1985.

• SEE PREVIOUS PAGE FOR CONCURRENCES LB#1/DL LB#1/DL LB#4/DL N0 ELD

• L01shan/mac JSteveg(iLB#1/DL

• MRushbrook h *BJYoungblood LB#1/DL KJabbour 07/24/85 /0/J /85 07/26/85 08/16/85 p/p/85 7 g(/85 ovak MDL[

MiThotfson y/85 to /zt/85 i

F . .

p. ,

7590-01 OCT 2 81995 Document Room, 1717 H Street, N. W., Washington, D. C., and at the Rockford Public Library, 215 N. Wyman Street, Rockford, Illinois, 61103, and the Wilmington Township Public Library, 202 S. Kankakee Street, Wilmington, Illinois 50481. The staff's technical evaluation of the exemption request will be published with the exemption and will also be available for inspection at all locations listed above. -

Dated at Bethesda, Maryland this g\fday of Ochh985.

FOR THE NUCLEAR REGULATORY COMMISSION Original signed byg ThomasM.Novak Thomas M. Novak, Assistant Director Division of Licensing Office of Nuclear Reactor Regulation DISTRIBUTION Docket File NRC PDR Local PDR PRC System NSIC LB#1 Rdg MRushbrook L01shan

)Stevens 4 ELD, Attorney JKopeck

/TMNovak HThompson

• SEE PREVIOUS CONCURRENCES LB#1:DL LB#1:DL LB#1:DL DELD LB#1:DL O f tok!L

• L01shan/mac JStevens *MRushbrook EChan BJYoungblood T vak 08/16/85 08/16/85 07/24/85 08/26/85 08/16/85 l0/k/85