ML20148J256

Application for Amend to License DPR-3,revising Tech Spec 3.1.1.1.2 to Change Shutdown Margin Switching Temp from 490 to 470 F.Fee Paid

ML20148J256
Person / Time
Site:	Yankee Rowe
Issue date:	03/23/1988
From:	Drawbridge B YANKEE ATOMIC ELECTRIC CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20148J261	List: ML20148J256 ML20148J270
References
FYR-88-37, NUDOCS 8803300217
Download: ML20148J256 (4)

Text

s, u Tel2 phone (617) 872-8100

'* ' TWX 710-380-7619 YANKEE ATOMIC ELECTRIC COMPANY f

y 1671 Worcester Road, Framingham, Massachusetts 01701 PC-210 March 23, 1988 FYR-88-37 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Reference:

(a) License No. DPR-3 (Docket No. 50-29)

Subject:

Request for Change to Technical Specification Requirements in Mode 3 Shutdown Margin

Dear Sir:

Pursuant to Section 50.59 of the Commission's Rules and Regulations, the Yankee Atomic Electric Company hereby requests the authorization to make the following changes:

Proposed Change Item 1 We propose to modify Technical Specification 3.1.1.1.2 to change the shutdown margin switching temperature f rom 4900F to 4700F. This change is also reflected in Note 2 of Technical Specification 3.3.2 Table 3.3-2, and Bases 3/4.1.1.1. Revised pages containing the proposed change are attached.

Item 2 A. Change Surveillance Requirement 4.1.1.2.1 to 4.1.1.1.2.1. e B. Relabel Subpart (a) to the above surveillance requirement as Subpart (b), and insert new Subpart (a) concerning the determination of shutdown margin following the detection of an inoperable control rod while in Mode 3. A revised page containing the proposed change is attached.

Reason for Change Item 1 The change will increase operational flexibility during Mode 3 operation. During Mode 3 operation with the nonreturn valves open, following L

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United States Nuclear Regulatory Commission March 23, 1988 Attention: Office of Nuclear Reactor Regulation Page 2 FYR 88-37 an unplanned shutdown, the average main coolant temperature often decreases to below 4900F. In addition, during coastdown it is possible to operate with average main coolant temperature less than 4900F in Mode 1, thereby, making a transition to Mode 3 with average main coolant temperature less than 4900F impossible to avoid. Both of these conditions have made large borations necessary in the past.

Item 2 A. This change merely corrects a typographical error.

B. This change corrects an omission in the Mode 3 shutdown margin surveillance requirement which dates back to the initial conversion to standard Technical Specifications at the Yankee plant.

Bases for Change Item 1 The current Technical Specification specifies two different shutdown margin requirements in Mode 3 depending on average main coolant temperature.

These requirements change at the transition temperature of 4900F. For temperatures greater than or equal to 4900F, the required shutdown margin is 6% op or greater as based on the conditions existing at 5160F. For temperatures greater than or equal to 3300F, but less than 4900F, the required shutdown margin is 5% op or greater as based on the conditions existing at 3300F. '"

These temperature ef fects on shutdown margin are graphically shown in Figure 1. The transition temperature on the shutdown margin requirement is still needed because nonautomatic operations of SI actuation and NRV closure are allowed below the transition temperature. The availabilities of these functions influence the shutdown margin requirement due to the response of the plant to MSLB. However, our evaluations of MSLB analyses show that the transition temperature can be changed from 4900F to 4700F as shown in Figure 1. There is a sufficient amount of shutdown margin to preclude recriticality during either the postulated MSLB accident with the automatic trip functions or without. Since the current transition temperature (4900F), to block the automatic trip functions, was basically chosen as a lower end of practical operating limit during full-power condition, changing it to 4700F is acceptable.

Item 2 There exists within standard Technical Specifications, a Mode 1 through 5 surveillance requirement concerning the determination of shutdown margin within one hour and once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter following the discovery of an inoperable control rod. During the conversion of Yankee Technical Specifications to standard Technical Specifications, this requirement was inadvertently left out of the Mode 3 specification.

United States Nuclear Regulatory Commission March 23, 1988 Attention: Office of Nuclear Reactor Regulation Page 3 FYR 88-37 .

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1 Safety Consideration  !

l Item 1 This change is requested in order to provide flexibility in plant ,

operation by lowering the transition temperature of shutdown margin t requirement in Mode 3. As such, this proposed change would not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated. This change merely lowers the trcnsition temperature for the automatic trip functions to actuate i SI and NRV closure as well as for shutdown margin requirements.

i Therefore, the change cannot increase the probability or  !'

consequences of an accident, as the shutdown margin will remain sufficient in Mode 3.

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2. Create the possibility of a new or different kind of accident from l any previously analyzed. This modification will not result in a new failure mechanism which could initiate an accident. Therefore, the .

proposed change will not create the possibility of a new or different kind of accident. ,

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3. Involve a significant reduction in a margin of safety. Our j evaluations show that shutdown margin provided by the proposed l 1 change is sufficient to preclude recriticality in the event of a  ;

postulated MSLB accident. Thus, this change does not involve a l

{ significant reduction in a margin of safety. '

i Item 2  !

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{ This change is requested to correct two administrative oversights, a 3

~4 typographical error, and the previous omission of a Mode 3 shutdown margin l surveillance requirement. As such, this proposed change would not: li

, 1. Involve a significant increase in the probability or consequences of l an occident previously evaluated.

2. Create the possibility of a new or different kind of accident from j i any previously analyzed.

3. Involve a significant reduction in a margin of safety.

Based on the consideration contained herein, it is concluded that there i is reasonable assurance that operation of the Yankee plant, consistent with the proposed Technical Specifications, will not endanger the health and safety of the public. This proposed change has been reviewed by the Nuclear Safety

Audit and Review Committee.

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'i United States Nuclear Regulatory Comission March 23, 1988

1. Attention: Office of Nuclear Reactor Regulation Page 4  ;

FYR 88-37 l 2 j An application fee of $150.00 is enclosed in accordance with 10CFR170.21. ,

i Schedule of Change f These changes to the Yankee Technical Specifications will be implemented i upon Comission approval. A timely review and approval of this submittal ,

would be appreciated.-

l l 1 We trust that you will find this submittal satisfactory; however, should you desire additional information, please contact us.

Very truly yours,  ;

YANKEE ATOMIC E CTRIC COMPANY

' db 4 B. L. Drawbridg .

) Vice President and Manager of Operations l BLD/16.46  ;

Attachment  ;

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COMMONWEALTH OF MASSACHUSETTS) 1

)ss MIDDLESEX COUNTY )

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Then personally appeared before me B. L. Drawbridge, who, being duly j sworn, did state that he is Vice President and Manager of Operations of Yankee

Atomic Electric Company, that he is duly authorized to execute and file the i f foregoing document in the name and on the behalf of Yankee Atomic Electric J Company and that the statements therein are true to the best of his knowledge l and belief.

i bb Robert H. Groce Notary Public My Commission Expires ' August 29, 1991 l

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