ML17194A392

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Forwards Evaluation of SEP Topic XV-19, Radiological Consequences of LOCA from Piping Breaks within Rcpb. Plant Adequately Designed Against LOCA
ML17194A392
Person / Time
Site: Dresden Constellation icon.png
Issue date: 01/05/1982
From: Crutchfield D
Office of Nuclear Reactor Regulation
To: Delgeorge L
COMMONWEALTH EDISON CO.
References
TASK-15-19, TASK-RR LSO5-82-01-003, LSO5-82-1-3, NUDOCS 8201110367
Download: ML17194A392 (6)
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Text

{{#Wiki_filter:** ~ -:c J *,. . '*P'.,_,-*.:. Docket No. 50-237 LSOS-82-01-003 Mr. L. Del George Director of Nuclear Licensing Commonwealth Edison Company Post Offf ce Box 767 Chicago, Illinois 60690

Dear Mr. Del George:

©'

SUBJECT:

DRESDEN 2 - SEP TOPIC XV-19, RADIOLOGICAL CONSEQUENCES OF LOSS OF COOLANT ACCl°DENT FROM PIPING BREAKS WITHIN THE REACTOR COOLANT PRESSURE BOUNDARY Colllll1onwealth*Edfson (T. Rausch) letter dated October 15, 1981, transmitted for our review your safety analysf$ report (SAR) of SEP Topic XV-19, Loss "Of Coolant Accidents Resulting From a Spectrum of Postulated Pfpfng Breaks . ~Jithfn the Reactor Coolant Pressure Boundary. Enclosed you w111 find our* evaluation of the radiological consequences of this topfc. The results of our staff's review indicates that the plant fs acceptably designed for con-trolling or mitigating the radfologfcal consequences of a lo_ss of coolant accident. This evaluation wf11 be a basic input to the integrated safety assessment for Dresden 2 unless you fdentify changes needed to reflect the as-built conditions at your facility. The assessment may be revfsed in the future ff your facility design is changed or ff the NRC crfterfa relating to this subject is.modified before the integrated assessment is complete. ~fncerely, sGol t>S "' C.$ c {I 1o)

Enclosure:

As stated cc w/enclosure: See next page NRC FORM 318 (10-80) NRCM 0240 Denn.is M. Crutchfield, Chief /lD.P~ operating Reactors Branch No. 5 6

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Df vf sf on of licensing OFFICIAL RECORD COPY USGPO: 1981-335-960

  • e Mr. L. DelGeorge cc Isham, Lincoln & Beale Counsel ors at Law.

One FirstNationalPlaza, 42nd Floor..

  • Chicago, Illinois *60603 Mr. Doug Scott

. Pl ant Superintendent.,* :,. R*ural Route #1 Morris,' Illinois 60450 U. S. Nuclear Regulatory Commission Resident. Inspectors Office Dresden Station *. RR #1 Morris, Illihois 60450 . Mary Jo Murray Assistant Attorney General Envir'onmental Control Division 188 w. Randolph Street Suite 2315 Chicago, Illinois 60601 Morris Pub 1 i c Library 604 Liberty Street

  • 'iorris, Illinois 60451

. Chairman Board of Supervisors of Grundy County *

  • Grundy County Courthouse i',*orri s, I 11 i noi s. 60450 Illinois Department of Nuclear Safety l 035 Outer Park Ori ve, 5th Floor.

Spri~gfield, Illinois 62704 . JJ. s. Environmental Protection Age*ncy 'Federal Activi-ties Brancll *. **

  • Region V Office ATTN:

Regional Radiation Representative 230 South*Dearb~rn Street Chicago, Illinois 60604 ~-* The Honorable Tom Corco.ran United States House of Representatives -r:,.. -Washington, D." C. 20515 John H. Frye, III, Chairman Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. c. 20555 *

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Danie~. Mi n~}~7.*...... Fi~;[;* ~-:::**~ *.** *. Counsel for Petitioners.;*.~*-:'*** *.*.

  • ~ (Citizens for a Better Environment).. "
  • Suite 1600, 59 E. Van Buren Street.
  • Chicago, Illinois: 60605-_

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. DRESDEN-2 ** ~- :<* :-_:.;'.k'~~l~;~~ :-..i-* XV-19 LOSS *OF COOLANT ACCIDENTS RESULTING FROM SPECTRUM Of POSTULATED

  • PIPING BREAKS WITHIN THE REACTOR COOLANT PRESSURE BOUNDARY'~~~'.k'<.

-, ~~ '-* *' - ,A* ~ , **'T -~::. :*._... * :'.<-~~~.':;* ~~:_L:,,~:-~~-**_'.; __ :.. ::'-'~J-.. :_:'~,.:~-:'_-- *.*'.'> -~:*r.*;.- -... ::'.~*:*: ~. --. I. INTRODUCTION. Loss-of-coolant accidents (LOCA 's) are* p~stulated *b~eaks.. "in,*th~r.-~eactor'.:*/: -~\\--~_~: :* *.. - coola~t pressure boundary resulting in a. loss. of:rea.ctof.;:':mol~~t'~~~::a rat~.~~~~:/>.~'"\\:::, -~~-: :. 1-in excess of the capability of the reactor coolant makeup *system. : LOCA's. result in excessive fuel damage or melt unless coolant i.s repleni~hed_ *. Excessive fuel damage can result in significant radiological consequences to* the environment via leakage from the containment. SE~ Topic. XV-19 is intended* t.o assure that the radiological consequences of a des.ign basis. LQtA from containment leakage and leakage from an outboard main steam isolat:iion*valve. (MSIV) are within. the exposure guideline values of 10 CFR Part. 100, *. II. REVIEW CR1TERIA Section 50.34 of 10 CFR Part 50 require~ that each app~icant for a construction perm.it or operatfng. license provide an analysis and evaluation of the design and performance of structures, systems, and components of the facility with the

  • objective of assessing the risk to public health and safety resulti,ng from operation of the facility. The LOCA is one of the *postulated' accidents used to evaluate the adequacy of these structures, systems, and ~omponents with respect to*the public health and safety.

In addition, 10 CFR Part 100.11 provides an acceptable dose conseq_uence li~it :~

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for reactor siting. ~-* III. RELATED SAFETY TOPICS ~- Topic II-2.C, "Atmospheric Transport. and Diffusion Characteristi.cs for Acci-dent Analysis" provides -the meteorological data used to evaluate. the offsite

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- 2 ~:~~:... :~. ~- -. doses. Topic III-5.A, "Effects of Pipe Breaks onStruct~s:,_~¥~~-~~~~nd:

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Components Inside Containment" ensures that the ~ility to achieve saf~ ~hut;..>>.:_'<"/\\.; __.

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...,, ~ :::::.:. down or mitigate the consequences of an accident are maintained:_~~- Various . :._:;:;~-~*~,,,?< -* other t~pics examine. such areas a~ c~ntai~;.,~{ inte9rii;' ~d ;$~~~~,i'~~. ~~st -*. *.*... accident chemistry, ESF systems, conbustible gas control and contr~l *room..

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IV.. REVIEW GUIDELINES J :

  • The review of the radiological consequences of a LOCA was conducted in* accord---,

ance with the Appendices A, B, and C to Standard Review Plan 15.6.5* a~d Regula-* tory Guide 1.3. The plant is adequateiy designed against* a LOCA and the dose mitigating features are acceptable only if the resulting. doses at the exclusion area and low population zone boundaries are within the.guideline, values of 10 CFR Part 100. V. EVALUATION In the licensee's submittal to the NRC, the licensee did not provide a new evaluation of the offsite radiological consequences due to a loss-of-coolant accident (LOCA), but simply provided the section of the FSAR (revised March* 22, 1968) which concluded* that the offsite radiological consequences

  • following this postulated accident were a very small fraction of the 10 CFR Part 100 guidelines; this submittal did not follow the curre_nt guidance.

We reviewed this submittal and concluded that there was insufficient detail in the analysis to complete the rev_iew on the basis of the informatioll supplied. Therefore, the staff performed an independent review of the. offsite radiological consequences 'following a postulated. loss~of~cool~nt

  • accident, using up-to-date methods with conservative assumptions, as appropriate.

1* .,,.;e-.. . *. *. v' *..... *. **.* * * &;*. ;):!gi;. *.:'~~~;.;. *Eli**~;f! 7 ** * *.. Assuming an. outboard MSIV. to be leaking at."276 standard :cubic. feet 'per day'i':~ :':'.:*!<;"**. :< (which.is. somewhat conser~ati~e rel~ti~e to'*:~ecent' me~~;~~-~i';?~~::*;~:~~h~v~*:-{~'.,:'.. *.:'....,,.,,.*. e** 0

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  • estimated a thirty hour _delay time for the**~IV portion of the'.~:leaka*ge~* based,-

upon at least an eighty foot *1ength of seismical ly*qu~l ified maiia stearri > >~~-.*. line downstream of_ the leaking MSIV. Le~kage is. assumed to'o~c~; a.t,~~o~-~d::,.** >' :*:. . /.level.. atthe. tur~-i~e-stop ~~~;ve. i_n-:the turbi*~{b~~i~~ng. "<~-..:._**:t:*_;L:~*- ;\\)~:-::,:~-' _,-:*..,<:*:.,..,.. *... The total offsite radiological consequences of the LOCA,:*"includj;~ containment. :*. - ... ~-. leakage, are calculated to be 36 Rem *to the thyroid and 2* Rem. *t<<>:*.u,e-:whole.:-_ ~ _ body at the EAB and 230 Rem to the thyroid* and less than 1 Rem tc 1:he who le body at the LPZ. These are within the offsite radiological conSe1JUence; gui~elines of 10 CFR Part 100. VI. CONCLUSION We have evaluated the off site radiologi.cal consequences* of* a* loss-of-coolant for Dresden Unit 2 and find that the mitigative features are acceptable and the plant is adequately designed against the LOCA. -~... ~ .~. --**..--.--.---~-...----..,... ****----

/., 1" _, \\ 1* ~-.. PAR~ERS USED IN THE E~TU.1ATE ~F

  • LOSS-OF-COOLANT ACCIDENT DOSES Power.Level Operating Time Primary Containemnt Leak *Rate Fraction of Core Inventory Released to Containment Atmosphere:

Iodines

  • Noble Gases Drywell Free Volume Iodine Composition Elemental Particulate Organic Filter Efficiencies Elemental Particulate Organic Relative,Concentration (X/Q)

EAB: 0-2 hr @ 805 m Elevated Ground level LPZ: 0-2 hr @ 8050 m (Elevated) 2-8. hr 8-24 hr 1-4 d 4-30 d

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--~- 2577 megawatts, thermaJ

  • . 3.years\\::::::.~-: *.,-.

<J~~if~~~*~:' - 2.0 percent per day

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25 *-percent

  • 100 percent : *~.*

158,00o,ft3. 91 percent* *

  • 5 percent 4 percent.

. 90_ percent 90 percent* 70 percent 2~2 x lo-5 sec/nf 2~6 x 10-4 sec/niJ 3~1 x Jo-6 sec/~ - 1..l-_x:.1~-D seclm3 7~6 x 10-7 sec/ri3 3~2 x 10-7 sec/nr3 _ 9~4 x 10-8 sec/m3

  • 1-4 days (Grou~d level) 4-30 days (Ground level) 3.0 x 10-6 sec/m3*:::
  • _-.
  • "*:>:'.* '-0 -<--- *
  • 9~4 x 10-7 sec/m3}}
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