B12685, Provides Status of Four Concerns Along W/Remaining Info to Resolve SEP Topic III-5.B, High Energy Pipe Break Outside Containment. Items Considered Adequately Addressed.Written Confirmation Requested

Provides Status of Four Concerns Along W/Remaining Info to Resolve SEP Topic III-5.B, High Energy Pipe Break Outside Containment. Items Considered Adequately Addressed.Written Confirmation Requested

ML20236D108
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	10/23/1987
From:	Mroczka E, Sears C CONNECTICUT YANKEE ATOMIC POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
TASK-03-05.B, TASK-3-5.B, TASK-RR B12685, TAC-51936, NUDOCS 8710280023
Download: ML20236D108 (9)

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D s'l ATOMIC POWER COMPANY t

C CONNECTICUT YANKEE TELEPHOk P.o. DoX 270 B E R L I N, CONNECTICUT HARTFoRo, CONNECTICUT 06141 0270 l

l l 203 665-50 1 1 October 23,1987 1

Docket No. 50-213  !

1 B12685 e

h U.S. Nuclear Regulatory Commission Q $

Attn: Document Control Desk N :t I Washington, D.C. 20555 4

> d ,

Reference:

(1) D. M. Crutchfield letter to W. G. Counsil, SEP Topic 111.54-- )

"High Energy Pipe Break Outside Containment," dated MayY0, 2- q 1982. o a

Haddam Neck Plant Resolution of Pipe Breaks Outside Containment Issue (TAC 51936)

In Reference (1) the NRC Staf f evaluated Connecticut Yankee Atomic Power Company's (CYAPCO) safety assessment report on SEP Topic III.5.B--High Energy Pipe Breaks Outside Containment. Four items required resolution:

A. Verification that flooding and spray effects of leakage cracks have been fully addressed, B. Evaluation of postulated breaks in the auxiliary feedwater system, C. Clarification of the jet impingement criteria utilized in the evaluation of piping in the primary auxiliary building, and D. Evaluation of the effects of turbine extraction steam line breaks on the switchgear room.

CYAP O summarized the status of these four concerns at the time the ISAP report ) was prepared.

With this letter CYAPCO is providing the status of these four concerns along with the remaining information to resolve the high energy pipe break outside containment issue for the Haddam Neck Plant.

8710200023 871023 PDR ADDCK 05000213 P PDR j

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1 (1) Integrated Safety Assessment Program, Final Report, B12349, dated ]

December 12,1986. I

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j U. S". Nuclear Regulatory Commission j

'B12685/Page 2  :

October 23, 1987:.

J Item A ~

CYAPCO has provided a satisfactory response to this item by letter dated February 12, 1975.(2i  !

1 Item B i The Staff ' concluded by letter dated ' January 27, 1987(3) that CYAPCO's augmented in-service inspection' (ISI) program would resolve; all - staff ' concerns associated with this item. CYAPCO  ;

descrjbed the augmented ISI program by' letter dated December 5, 1 1986.t4)

Item C :

- Criter.ia for pipe whip analysis and jet impingement were provided to the Staff as Attachment ! by letter dated November -18, 1986.(5) .

CYAPCO stated in this letter. that evaluation of certain ~ pipe breaks in j the primary aux.iliary. building was' ongoing. Attachment I of this '

letter provides the results of that evaluation.

Item D  ;

- By letter dated November 18, 1986,(5) CYAPCO provided the Staff information on this item. Results of calculation 78-818-228-GC are summarized and provided with this letter as Attachment II.

Conclusion With the information provided in this letter CYAPCO considers Items (A), (B), (C),

and (D) to be adequately addressed. There are no other open items on the high energy pipe breaks outside containment topic.

(2) D. C. Switzer letter to R. A. Purple, "Haddam Neck Plant--Review of a Potential Causes of Flooding of Safety-Related Equipment," dated l February 12,1975. I (3) F. 3. Miraglia letter to E. 3. Mroczka, " Augmented Inservice Inspection and Resolution of Environmental Qualification and High Energy Line Break {

Issues," dated January 27,1987. l l

(4) E. 3. Mroczka letter to C.1. Grimes, " Environmental Qualification of l Equipment Outside Containment and High Energy Line Breaks," B12318, dated December 5,1986.

(5) 3. F. Opeka letter to C.1. Grimes, " Integrated Safety Assessment Program," 1 B12293, dated November 18,1986. j J

U' S. Nuclear Regulatory Commission

. B12685/Page 3 October 23,1987-CYAPCO requests that the Staff provide to CYAPCO written confirmation of closure of these SEP open items.-

I Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY

$ .b . h s j E. 3. Mroczka 4 '

Senior Vice President By: C. F. Sears Vice President cc: W. T. Russell, Region I Administrator F. M. Akstulewicz, NRC Project Manager, Haddam Neck Plant

3. T. Shediosky, Resident Inspector, Haddam Neck Plant

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' Docket No. 50-213 -

B12685 l

Attachment I Haddam Neck Plant High Energy Pipe Break Evaluation i

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L . Attachment I j Bi2685/Page1 Clarification of the Jet Impingement Criteria Utilized in the Evaluation Of Piping in the Primary Auxiliary Building Discussion The high energy lines in the Primary Auxiliary Building (PAB) that were evaluated in this study included the charging, auxiliary steam, letdown, and steam generator l blowdown lines. l i

A. Charging Lines in the PAB I With respect to postulated charging line breaks in the PAB, the only system inside l the PAB which is required for shutdown method (l) 1 or 2 is the charging system -l i+ 3el f. The charging system is used in shutdown methods 1 and 2 to control reactivity and to maintain pressurizer level, accounting for coolant shrink during l cooldown and RCS ' leakage. However, in the event of a charging line break, j

- sufficient time exists to isolate the charging system and line up the alternate charging path (loop fill header) to provide RCS makeup. Interactions between the charging line break and other portions of the charging system are as follows: j o The charging line is not subject to pipe whip concerns based on the fact that it is separated from the RCS by a check valve and thus lacks a sustained high energy source.

o The blowdown force of the charging pump discharge. load has been analyzed using the rjteria shown of Attachment I by letter dated l November 18, 1986. / Pipe whip is not considered credible for a l blowdown force of approximately 230 lbs. on a schedule 160 pipe. l o A charging line break could potentially result in jet impingement damage to the cabling and air lines to valves CH-MOV-344 and CH AOV-295. These valves are located in parallel in the loop fill line, and one of these valves is required to open in order to use this makeup ,

path. However, these valves are accessible in the PAB, and sufficient  !

time exists to isolate charging and manually line up to the loop fill path.

(1) Method 1--Main Feedwater Pumps (requires off-site power)

Method 2--Steam Driven Auxiliary Feedwater Pumps (two pipe routings) i Method 3--Primary System Feed and Bleed .

(Method 1 is only assumed to be available if the postulated break does not cause a reactor / turbine trip.)

(2) 3. F. Opeka letter to C. I. Grimes, " Integrated Safety Assessment Program,"

B12293, dated November 18,1986.

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Attachment 1 l.

B12685/Page 2 I

With a break in the normal charging header, both charging pumps would be ,

considered inoperable and the plarit would be shut down. The RCS would be kept {

hot by decay heat and/or operation of the reactor coolant pumps thus precluding 1 I

the need for make-up for shrink, and pressurizer heaters would maintain RCS pressure for subcooled margin. With letdown isolated (letdown isolation is being made single failure proof during the current refueling outage), the only RCS makeup required would be to compensate for RCS leakage (Technical Specification maximum allowable is 10 gpm) since a charging line break outside i containment does not directly result in a significant RCS inventory loss. Even at this leak rate, the pressurizer would not drain substantially during the one (1) hour period. During operating conditions, it is not anticipated that RCS leakage will be greater than one (1) gpm due to seal and packing leakage. However, it is noted that during this time, makeup (up to approximately 10 gpm) can still be provided to the RCS via RCP seal water injection. This is equal to the maximum RCS loss rate allowed by the Technical Specifications. With charging aligned to the loop fill header, safe shutdown could be achieved using either method I or method 2.

The other high energy systems considered in the PAB all meet the separation / size j differential criteria, and can be isolated outside the PAB. Specific detail are as '

follows:

B. Auxiliary Steam Header in the PAB This system runs th.oughout the plant providing low-pressure steam for various purposes. As a result of a plant survey, one system interaction was noted:

1. A six-inch,110 psig heating steam main enters the PAB above ground level near the west wall entrance. This line continues to be run to the first-and second-stage evaporator rebollers (E-43-1 A and E-44-1 A).

This line runs directly above the component cooling pump P-13-1B. In the remote event of a pipe break, the component cooling pump could be af fected. However, the component cooling water system is not safety related and service water can be used in the residual heat removal (RHR) heat exchangers for cooldown. All three shutdown methods would remain available.

C. Letdown (Bleed) Lines in the PAB This system runs from the three letdown orifices through the nonregenerative heat exchanger E-76-1 A to the pressure control i valve LD-PCV-ll3.  !

The system. runs in the same pipe trench as the required shutdown lines (charging and RHR). ' However, a two-inch line will not damage lines of equal size or greater. The charging and RHR lines are larger. Therefore, all shutdown methods remain available.

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5 Attachment I B12685/Page 3 D. Steam Generator Blowdown System The steam generator blowdown system is defined as the piping from the reactor containment penetrations through the piping trench to the blowdown tank in the PAB. A whipping pipe in this system would have no effect because of isolation characteristics and because a whipping pipe cannot damage another pipe of equal size or larger.

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Docket No. 50-213 B12685 j Attachment II Haddam Neck Plant Structural Evaluation of the Effects of Extraction Steam Line Break on the Switchgear Room Wall -

October 1987

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, Attachment 11 B12685/Page1 Haddam Neck Plant Structural Evaluation of the Effects of Extraction Steam Line Break on the Switchgear Room Wall An analysis of the Haddam Neck switchgear room wall along column line D'was performed by CYAPCO. The analysis considered the jet impingement loading placed on the wall due to an extraction steam line break approximately 8 feet from the switchgear room wall. The switchgear room wall west side consists of a 12-inch filled concrete block wall. The east side consists of a 1/4-inch-thick carbon steel plate with a grid of W5 x 18.5 wide flange beams integrally welded to the plate. The wide flange stiffeners are spaced approximately 48 inches on center and run both horizontally and vertically. The plate is in contact with the concrete block wall. The plate and stiffeners are welded to the main structural load carrying members of the building.

The jet impingement load due to an extraction steam line break would act on the block wall side. The switchgear room is located east of the wall. Analysis has shown that the switchgear room wall syste'm will remain intact when subjected to the additional imposed jet impingement load acting in conjunction with all credible loads. Furthermore, no yielding of the steel plate and grid system would occur. Therefore, no damage will occur to any components within the switchgear room.

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