ML20079S182

Final Deficiency Rept Re Tornado Missile Shields for Fuel Storage Bldg.Initially Reported on 821110.Probability Analysis Performed,Revealing Acceptably Low Risk.Appropriate FSAR Sections Will Be Reviewed

ML20079S182
Person / Time
Site:	Seabrook
Issue date:	12/29/1983
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO.
To:	Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
SBN-605, NUDOCS 8402030235
Download: ML20079S182 (4)

Text

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. y PUEBLIC BERVICE stAa m m s w a rasi = 4 s o me.:

Compartyof New HampeNro 1671 Worcester Road Framinehom, Massachusetts 01701 (617) - 872 - 8100 December 29, 1983 SBN- 605 T.F. Q2.2.2 United States Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 Attention: Mr. Richard W. Starostecki, Director Division of Project and Resident Programs

References:

(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) Telecon of November 10, 1982, A. L. Legendre (YAEC) to Eugene Kelly (NRC Region I)

(c) PSNH Letter, dated December 14, 1982, " Interim 10CFR50.55(e) Report; Tornado Missile Shields for Fuel Storage Building," J. DeVincentis to R. W. Starostecki (d) PSNH Letter, dated March 31, 1983, " Interim 10CFR50.55(e)

Report; Tornado Missile Shields for Fuel Storage Building,"

J. DeVincentis to R. W. Starostecki (e) PSNH Letter, dated July 14, 1983, " Interim 10CFR50.55(e)

Report; Tornado Missile Shields for Fuel Storage Building,"

J. DeVincentis to R. W. Starostecki (f) PSNH Letter, dated November 28, 1983, " Interim 10CFR50.55(e) Report; Tornado Missile Shields for Fuel Storage Building," J. DeVincentis to R. W. Starostecki

Subject:

Final 10CFR50.55(e) Report; Tornado Missile Shields for Fuel Storage Building

Dear Sir:

On November 10, 1982, we reported a potential 10CFR50.55(e) deficiency

[ Reference (b)] regarding the adequacy of Tornado Missilc Shield Protection on the North and West walls of the Fuel Storage Building.

It has been determined that this item is not a reportable deficiency under 10CFR50.55(e). The following infor ation is provided in accordance with 10CFR50.55(e)(3), and is considered to be a final report on this item.

S O (

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LUnited States Nuclear Regulatory Commission December 29, 1983 Attention: Mr. Richard W. Starostecki, Director Page 2 Description of Deficiency

' The NRC Resident, Inspector reported unresolved item 443/82-13-02 for Tornado Missile Shields which are located on the North and West walls of the Fuel Storage Building above Elevation 64'-0" where ductwork penetrates the walls.- Prior to the installation of ductwork, a clear line of sight was available through the penetration to a one-foot thick floor slab located at Elevation 64'-0".

.The floor slabs also contain openings through which a tornado missile could travel and strike the storage pool or its auxiliaries located below.

Analysis of Safety Implications The FSAR, Section 3.5.2, states that the Spent Fuel Cooling / Cleanup System and storage pool is protected against tornado missiles.

Under the present configurations, a tornado missile could enter the Fuel Storage Building through the North wall opening and enter the spent fuel area

'through an_ opening in the Elevation 64'-0" slabs and damage spent fuel or the Pool. Cooling System. -This is a violation of the FSAR design bases.

Corrective Action Taken The evaluation of safety implications resulted in the initiation of a detailed review of all exterior openings in Category 1 buildings. A total of thirty (30) openings were~ identified as potential tornado missile targets.

These - openings were categorized into three groups.

1. Openings protected by missile shields, but the adequacy of those shields was questionable (area of coverage).

2.- Opening vulnerable to sudden'depressurization due to damage by a missile hit.-

l

3. Openings identified during design review which do not have missile shields.

A probability analysis was performed based on the assumption that Unit 1 is operational, and Unit 2 under construction (this assumption is conservative because the number of potential missiles is maximized).

I The analysis was initiated with a field inspection that identified types of potential missiles and their relative storage locations with respect to i- physical plant location and the missile criteria of the Standard Review Plan

! (SRP). The analysis concluded that there is an average annual probability of l' a plant' mis'sile entrance of 1.2 x 10-6 for all openings in Category 1 l buildings. It is concluded that the probabilities of missile entry for individual openings or the total plant are acceptably low and consistent with guidelines delineated-in Section 2.2.3 of NUREG-0800.

J-

. p United States Nuclear Regulatory Commission December 29, 1983 Attention: Mr. Richard W. Starostecki, Director Page 3 Important conservatisms in the analysis are:

1. When Unit 2 is completed the maximum number of potential missiles available will decrease and therefore the missile strike probabilities will decrease.

2. - Probabilities are for missile entrance and not missile impact on safety-related components. If such calculations were carried out in a more detailed analysis, it is likely that there would be no opening that would lead to a safety-related component hit probability greater than about 10-8 per year.

3. The NRC Tornado Region I upperbound windspeed of 360 mph was assigned a probability of about 10-7 for this analysis. A proposed American

' Nuclear Society Standard entitled " Guidelines for Estimating Tornado Missiles and Extreme Wind Characteristics at Nuclear Power Sites",

(proposed ANS 2.3, ANSI N-178, Draft 2, Revision 4, April 1980) estimates that the 10-7 annual probability tornado windspeed is about 225 mph.

Although this is a proposed standard in draft form, it does represent a consensus of tornado experts and is a more realistic characterization of upperbound tornado windspeed for the Seabrook site.

We will review the appropriate FSAR sections to determine if a revision is warranted.

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY n)

John DeVincentis Project Manager cc: Atomic Safety and Licensing Board Service List Director, Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555

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William S. Jordan, III, Esquire 'Brentwood Board of Selectmen

'Harmon'& Weiss RED Dalton Road

-1725'I' Street,LN.W. Suite 506 Brentwood, New Hampshire 03833 Washington, DC 20006 Roy P. Lessy,-Jr.. Esquire

-Office of the Executive Legal Director . Edward F. Meany U.S. Nuclear Regulatory Commission . Designated Representative of Washington, DC 20555 the Town of Rye 155 Washington Road

. Robert A. Backus, Esquire' ~ Rye, NH 03870 116 Lowell Street P.O.. Box-516~ Calvin A. Canney Mancehster, NH 03105 City Manager.

City' Hall Philip Ahrens,-Esquire. 126 Daniel Street Assistant Attorney General Portsmouth, NH 03801 Department of the Attorney General Augusta, ME 04333 Dana Bisbee, Esquire Assistant Attorney General Mr. John B. Tanzer Office of the Attorney General Designated Representative of 208 State House Annex

the Town.of-Hampton Concord, NH 03842 5 Morningside Drive Hampton,.tni 03842 Anne Verge, Chairperson Board of Selectmen Roberta'C. Pevear Town Hall Designated Representative of South Hampton, NH 03842 the Town of Hampton Falls Drinkwater Road Patrick J. McKeon Hampton Falls, NH 03844 Selectmen's Office 10 Central Road Mrs. Sandra Gavutis .

Rye, NH 03870 Designated Representative of-the Town of Kensington Carole F. Kagan, Esq.

RFD l- Atomic Safety and Licensing Board Panel East Kingston, NH 03827 U.S. Nuclear Regulatory Commission Jo Ann Shotwell, Esquire Assistant Attorney General Mr. Angie Machiros Environmental-Protection Bureau Chairman of the Board of Selectmen Department of the Attorney General Town of Newbury One Ashburton Place, 19th Floor Newbury, MA 01950

. Boston, MA 02108 Town Manager's Office Senator Gordon J. Humphrey Town Hall - Friend Street U.S.~ Senate Amesbury, Ma. 01913 Washington, DC 20510 (Attn: Tom Burack) Senator Gordon J. Humphrey 1 Pillsbury Street Diana P. Randall Concord, NH 03301 70 Collins Street (Attn: Herb Boynton)

SEabrook, NH 03874 i Richard E. Sullivan, Mayor Donald E. Chick City Hall Town Manager Newburyport, MA 01950 Town of Exeter 10 Front Street Exeter, NH 03833

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