ML17261B259

Forwards Draft Evaluation of SEP Topic XV-20, Radiological Consequences of Fuel Damaging Accidents (Inside & Outside Containment). Requests Confirmation Re Accuracy or Identification of Errors.Requests Related Matl Be Supplied

ML17261B259
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	03/20/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Counsil W CONNECTICUT YANKEE ATOMIC POWER CO.
References
TASK-15-20, TASK-RR LSO5-81-03-047, LSO5-81-3-47, NUDOCS 8104010489
Download: ML17261B259 (12)

Text

REGULATORY IN)

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SUBJECT:

Forwards draft evaluation of SEP Topic XV"20< "Radiological Consequences of Fuel Damaging Accidents (Inside 8 Outside Containment)

~ " Requests confirmation re accuracy or identification of errors, Requests related matl be supplied, DISTRIBUTION CODE:

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ACCESSION NBR:8100010089 DOC ~ DATE: 81/03/20 NOTARIZED:

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Connecticut Yankee Atomic Power, Co 05000213 AUTH,NAME AUTHOR AFFILIATION CRUTCHFIELDPD ~

Operating Reactors Branch 5

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Docket No. 50-213 LS05-81-03-047 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C, 20055 March 20, 1981

, OI Mr.

W. G.Counsil, Vice President Nuclear Engineering and Operations Connecticut Yankee Atomic Power Corp, Post Office Box 270 Hartford, Connecticut 06101

SUBJECT:

SEP TOPIC XV-20, RADIOLOGICAL CONSLQUENCES OF FUEL DAMAGING ACCIDENTS (INSIDE AND OUTSIDE CONTAINMENT) -

HADDAM NECK Enclosed is a copy of our draft evaluation of Systematic Evaluation Program Topic XV-20.

You are requested to examine the facts upon which the staff has based its evaluation and respond either by confirming that the facts are correct, or by identifying any errors.

If in error, please supply corrected information for the docket.

We encourage you to supply for the docket any other material related to these topics that might affect the staff's evaluation.

Your response within 30 days of the date you receive this letter is requested.

If no response is received within that time, we will assume that you have no corments or corrections.

Sincerely, Enclosure; Topic XV-20 cc w/encl osur e:

See next page Dennis M. Crutchfield, ief Operating Reactors Branch No.

5 Division of Licensing ggo/

5 LSD C>~)

81040>0 489

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W. G. Counsil HADDAN NECK PLANT DOCKET NO. 50-213 CC Day, Berry

& Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Superintendent Haddam Neck Plant RFD 81 Post Office Box 127E East Hampton, Connecticut 06424 Nr. James R. Himmelwright Northeast Utilities Service Company P. 0.

Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Town Hall

Haddam, Connecticut 06103 Connecticut Energy Agency ATTN:

Assistant Director Research and Policy Development Department of Planning and Energy Policy 20 Grand Street Hartford, Connecticut 06106 Director, Technical Assessment Division Office of Radiation Programs (AW-459)

U. S. Environmental Protection Agency Crystal Hall 02 Arlington, Virginia 20460 U. S. Environmental Protection

.Agency

. Region I Office ATTN:

E I S COORDINATOR JFK Federal Building

Boston, Massachusetts 02203 Resident Inspector Haddam Neck Nuclear Power Station c/o U. S.

NRC East Haddam Post Office East

Haddam, Connecticut 06423

ENCLOSURE HADDAM NECK XV-20 RADIOLOGICAL CONSEQUENCES OF FUEL DAMAGING ACCIDENTS I.

INTRODUCTION The safety objective of this topic is to assure that the offsite doses from fuel damaging accidents as a result of fuel handling inside and outside con-tainment are well within the guideline values of 10 CFR Part 100.

II.

REVIEW CRITERIA Section 50.34 of 10 CFR Part 50, "Contents of Applications:

Technical Information," require" that each applicant for a construction permit or operating 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 resulting from operation of the facility.

A fuel handling accident in the fuel handling and storage facility resulting in damage to fuel cladding and subsequent release of radioactive material is one of the postulated accidents used to evaluate the adequacy of these structures,

systems, and components with respect to the public health and safety.

10 CFR Part 100 provides Lhe acceptable dose consequences for siting of nuclear power plants.

III.

RELATED SAFETY TOPICS Topic II-2.C, "Atmospheric Transport and Diffusion Characteristics for Accident Analysis" provides the meteorological data used for calculating the offsite dose consequences.

The review of the fuel damaging accidents did not consider fuel damage as a result of'rops of the spent fuel cask or other heavy objects which can be carried either over an open reactor vessel or the spent fuel pool.

Review of the drops of casks and heavy objects is covered in two SEP Topics, IN-2, "Overhead Handling Systems-Cranes" and XV-21, "Spent Fuel Cask Drop Accidents."

IV.

REVIEW GUIDELINES Accidents resulting from the movement of fuel inside and outside containment were reviewed following the assumptions and procedures outlined in Standard Review Plan (SRP) Section 15.7.4 and Regulatory Guide 1.25.

The dose to an individual from a postulated fuel handling accident should be well within

the exposure guidelines of 10 CFR Part 100.

"Well within" the guidelines of 10 CFR Part 100 has been defined as less than 100 rem to the thyroid.

(Whole body doses are also examined but are not controlling due to the decay of the short-lived radioisotopes prior to fuel handling.)

This is based on the probability of this event relative to other events which are evaluated against 10 CFR Part 100 exposure guidelines.

The review considers single.failure, seismic design and equipment qualification only when the potential consequences might exceed the guidelines of 10 CFR Part 100 in the absence of containment isolation and effluent filtration.

V.

EVALUATION The assumptions used in the evaluation of the fuel handling accident are listed in Table l.

The fuel handling accident inside containment was considered in an earlier NRC evaluation as a result of a generic activity (Ref. 1).

In Reference (1),

we evaluated the potential consequences of a postulated fuel handling accident inside containment.

During fuel handling operations inside containment, the licensee operates the containment ventilation system in one of two modes.

In the first mode the containment is closed and the

',entilation flow is directed through internal charcoal filters.

These filters are safety grade (used for post LOCA dose mitigation) and would result in dose mitigation for fuel handling accidents inside containment when this ventilation mode is utilized.

In the event a fuel handling accident were to occur in this mode radioactivity would not be released to the environment since the containment is closed.

In the second

mode, the containment is purged during fuel movement operations.

We have reviewed existing plant procedures and have determined that the purge discharge would be directed through the Primary Auxiliary Building (PAB) charcoal filters and, therefore, credit was taken for these filters as indicated in Table 1.

The radiological consequences at the exclusion area boundary (EAB) are given in Table 2.

The doses at the EAB are controlling due to the short duration of the accident and the lower atmospheric dis-persion factors for the low population zone.

We have also reviewed the potential consequences of a postulated fuel hand-ling accident inside the spent fuel building.

During fuel handling operations in the spent fuel building a plant procedure review revealed that the charcoal filter in the ventilation discharge is not in service when fuel is being handled.

Without credit for the charcoal filters, the dose consequences at the site boundary are not well within the guidelines of 10 CFR Part 100,

however, the doses do not exceed the guidelines of 10 CFR Part 100.

The radiological consequences of the EAB are presented in Table 2. If the plant 1

procedures were modified to require ventilatfon discharge through charcoal filters. whenever spent fuel is being moved the dose consequences would be weT1 within the 'guidelines of 10 CFR Part 100.

The radiological con-sequences at the EAB assuming operation of the spent fuel building charcpal filters are presented in Table 2.'herefore, we recommend that the licensee modify the existing plant procedures to assure that exhaust flow from the spent fuel building passes.

through the charcoal filter prior to being discharged to the environment.

In addition, we recommend that the licensee incorporate technical specifications which will assure that the spent fuel building charcoal filter will provide the iodine removal efficiency assumed in our analysis.

VI.

CONCLUSIONS Based on the above evaluation, we conclude that the radiological consequences of a fuel handling accident inside containment are well within the guidelines of 10 CFR Part 100 and the SRP criteria are met.

However, the consequences of a fuel handling accident within the spent fuel building do not meet the acceptance criteria for SRP 15.7.4 if the charcoal filters are not in use.

Therefore, we recommend

1) that plant procedures be modified to specify exhaust flow through the charcoal filter whenever fuel with less than 60 days decay is being handled in the spent fuel building; 2) that the licensee incorporate surveillance requirements for the PAB and spent fuel building filters into the plant Technical Specifications to assure the filter efficiencies assumed in our analysis are met.

Because the doses for a fuel handling accident in the spent fuel building are within the guidelines of 10 CFR Part 100 and based on the probability of the accident and the conservatism of the calculation we conclude that operation in the current mode is acceptable and the recommended changes can be dealt with during the integrated assessment.

TABLE 1

ASSUMPTIONS USED FOR THE FUEL HANDLING ACCIDENT.

Power Level Operating Time Peaking Factor Number of Fuel Assemblies.

Damaged N'umber of Fuel Assemblies in Core Activity Release From Pool Decay Time Before Moving Fuel Filter Efficiency for Filter on Primary Auxiliary Building and the New and Spent Fuel Building Ventilating System

'-2 hr., X/9 Value, Exclusion Area Boundary (ground level release) 1862 Mwt 3 years 1.65 157 Regulatory Guide 1.25 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 1.0 x 10 sec/m r

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TABLE 2 CALCULATED DOSES FOR FUEL HANDLING ACCIDENTS Exclusion Area Bounda'ry Doses from:

1)

Accident in Fuel Handling Building

Doses, Rem

~Th i

~llh 1

d a) without filter b) with filter 2)

Accident Inside Containment 210 21 21 0.7 0.7 0.7

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'EFERENCES 1.

Letter, D. L. Ziemann to W.

G. Counsil dated December 20, 1979, Transmitting the Safety Evaluation for Fuel Handling. Accident Inside Containment.

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2.

Letter, W.

G. Counsil to D. L. Ziemann, March 25, 1980, "Haddam Neck Plant Fuel Storage Building."