ML20072H272

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Forwards Responses to NRC Questions Re Util 811016 Preliminary Rept on Hydrogen Ignition Sys & 821229 Submittal Concerning Degraded Core Hydrogen Control,Per 830303 Telcon
ML20072H272
Person / Time
Site: Clinton Constellation icon.png
Issue date: 03/21/1983
From: Wuller G
ILLINOIS POWER CO.
To: Schwencer A
Office of Nuclear Reactor Regulation
References
L30-83(03-21)6, L30-83(3-21)6, U-0619, U-619, NUDOCS 8303290371
Download: ML20072H272 (3)


Text

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TlHnnia Power Company $$8!(03-21)6 500 SOUTH 27TH STREET. P. O. BOX 511. DECATUR. ILLINOIS 62525-1805 Docket No. 50-461 March 21, 1983 Director of Nuclear Reactor Regulation Attention: Mr. A. Schwencer, Chief Licensing Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Schwencer:

Subj ect : Clinton Power Station Unit 1 Degraded Core Hydrogen Control

References:

1) IP letter U-0309 10/16/81, G. E. Wuller to W. R. Butler, NRC, Preliminary Report on the Hydrogen Ignition System for the Clinton Power Station
2) IP letter U-0590 12/29/82, G. E. Wuller to A. Schwencer, NRC; submittal of responses to NRC Staff questions on degraded core hydrogen control.
3) Telcon on 3/3/83 between NRC (H. Abelson and A. Notafrancesco) and IP (E. Kant, J. Shepard, J. Peterson).

References (1) and (2) provided information on the Clinton Hydrogen Ignition System. During the recent telephone conference (reference 3), we were requested to give further information or clarification on six questions / concerns generated by the NRC Staff review. Attached is the Illinois Power response to the verbal questions.

Sincerely, G. E. Wuller Supervisor-Licensing Nuclear Station Engineering GEW/jmm

'I attachment cc: Dr. H. Abelson, NRC Clinton Project Ihnager Mr. L. Ruth, NRC CSB Mr. A. Notafrancesco, NRC CSB h[/)E)l Mr. H. H. Livermore, NRC Resident Inspector Illinois Department of Nuclear Safety C303290371 830321 PDR ADOCK 05000461 A

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Attachment to U-0619

. March.21, 1983 Question 1.

How many circuit breakers are in Clinton's design?

, Response There are six (6) 120V breakers per division serving 10-12 igniters each for a total of twelve circuir breakers. This design is significantly. improved over other systems licensed by the NRC because fewer igniters are. lost when a circuit breaker. opens.

Question 2 There appears to be an error in the elevation at' azimuth 309 in Figure 8-1 (reference 2). The. figure specified el. 704'-0".

Response

The Staff is right; the correct elevation is 764'-0".

Question 3 There was concern whether the open areas at the various levels within' containment (Question 6 of-Reference 2) are in-line or offset.

Response

The open areas are, for the most part, in line with each other such that containment spray can pass from one elevation;to the next. This assurotion is important in applying the generic application of containment spray carryover to the wetwell.

Question 4 How many igniters are in the wetwell?

Response

Our current system design includes twelve igniters irt the wetwell region. This is three more than the nina shown in the preliminary design.

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Attachment to U-0619 March 21, 1983 Page 2

. Question 5 A) Reference 1, page 18, shows 6 2,156 lbs of Zircaloy. while the FSAR gives a value of 65,100. Resolve the conflict.

B) The table on Page D-i- (ref.1) shows eight .(8) vacuum breakers, while figure 8-1 (ref. 2) shows only four (4). Explain.

Response

A) The FSAR (Table 6.2-52) value of 65,100 lbs includes the weight of the spacers. In our. analysis'only the cladding surrounding the active fuel was assumed.

B) There is no conflict. Figure 8-1 shows 4 sets of vacuum breakers. Each set has two vacuum breakers in series totaling eight (8) breakers.

Question 6 2

The vacuum breaker flow area of 2.67 ft appears incorrect. See page D-i of reference 1.

Response

2 The Staff is correcy. The flow area should be 0.267 ft each rather than 2.67 ft .

Ingidentally, the flow area quoted for Grand Gulf 1s not 3.27 ft . Grand Gulf changed their flow area to 1.09 ft2 (total) in a11ater NRC submittal.

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