BECO-86-123, Forwards Revised Tech Spec Page 204A,incorporating Modified Footnote Ref in 811002 Application for Amend 49 to License DPR-35 Re Spiral Unloading of Fuel Cells to Facilitate Insp

Forwards Revised Tech Spec Page 204A,incorporating Modified Footnote Ref in 811002 Application for Amend 49 to License DPR-35 Re Spiral Unloading of Fuel Cells to Facilitate Insp

ML20212Q281
Person / Time
Site:	Pilgrim
Issue date:	08/28/1986
From:	Lydon J BOSTON EDISON CO.
To:	Zwolinski J Office of Nuclear Reactor Regulation
References
BECO-86-123, NUDOCS 8609040147
Download: ML20212Q281 (3)

Text

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General Offices 800 Boylston Street Boston, Massachusetts 02199 1

Janus M. Lydon August 28, 1986 Chief operating Officer BECo 86-123 1

Mr. John A. Zwolinski, Director BHR Project Directorate #1 i Division of Licensing

, Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission i Washington, D. C. 20555

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License DPR-35 Docket 50-293 d

i

Dear Mr. Zwolinski:

Bases Change: Footnote to Spiral Unioading

References:

(a) Boston Edison letter of September 22, 1981 i

(b) NRC letter of October 2, 1981 (Amendment No. 49 to Facility Operating License No. DPR-35)

Boston Edison has identified the need to modify a footnote to Section 3.108.,

" Core Monitoring" of the Bases, found on page 204A. This footnote was l

proposed in Reference (a) and emplaced into our technical specifications as Amendment No. 49 by Reference (b). Currently this footnote states:

' During the 1981 refueling outage, prior to initiating spiral unloading,

the central controlled cell will be removed to facilitate inspection of i

the Core Spray Spargers.

I The revision to Bases will state:

During selected refueling outages, prior to initiating spiral unloading, the central controlled cell will be removed to facilitate inspection of the Core Spray Spargers, r

Reason For Change A spiral unloading pattern is one by which the fuel in the outermost cells (four fuel bundles surrounding a control blade) is removed first. Unioading

' continues by removing the remaining outermost fuel cell by cell. The center cell will be the last removed. Spiral loading and unloading precludes the creation of fluxtraps.

8609040147 860828 . /80 PDR ADOCK 05000293 PEH4 6,5 P

BOSTON EDISON COMPANY Page 2 By letter of September 1,1981, Boston Edison committed to perform a more in depth inspection of the Co'e Spray Spargers during the 1981 refueling outage.

The footnote added in Amendment No. 49 facilitated that inspection by permitting the unloading of the center cell first, which allowed the mounting of the equipment necessary to perform the inspection prior to full core unloading. This provided an earlier indication of the Core Spray Sparger's condition.

During Refueling Outage #7, and possibly during future refuelings, Boston Edison wishes to employ the same inspection technique to inspect the Core Spray Spargers. This method will allow us more time to develop and implement any repairs indicated necessary by the inspection, and thereby reduce the potential adverse impact of such action on the duration of a refueling.

A rev sed page 204A is included as an attachment to this submittal. You are i

requested to remove existing page 204A and insert new page 204A into your Controlled Copy of Pilgrim Nuclear Power Station Technical Specifications.

Should you wish further information on this issue, please contact us.

Very truly yours, c

6 aames M. Lydon

3.10 BASES:

8. Core Monttoring The SRM's are provided to monitor the core during periods of station shutdown and to guide the operator during refueling operations and station startup.

Requiring two operable SRM's in or adjacent to any core quadrant where fuel or control rods are being moved assures adequate monitoring of that quadrant during such alterations. The requirement of 3 counts per second provides assurance that neutron flux is being monitored and insures that startup is conducted only if the source range flux level is above the minimum assumed in the control rod accident.

The limiting conditions for operation of the SRM subsysten of the Neutrcn Monitoring System are derived from the Station Nuclear Safety Operational Analysis (Appendix G) and a functional analysis of the neutron monitoring system. The specification is based on the Operational Nuclear Safety Requirements in subsection 7.5.10 of the Safety Analysis Report.

A spiral unloading program is one by which the fuel is in the outermost cells (four fuel bundles surrounding a control blade) is removed first. Unloading continues by removing the rernaining outermost fuel cell by cell. The center cell will be the last removea. Spiral loading is the reverse of unloading. Spiral unloading and reloading will preclude the creation of flux traps (moderator filled cavities surrounded on all sides by fuel).

During spiral unloading, the SRM's shall have an initial count rate of > 3 cps with all rods fully inserted. The count rate will diminish during fuel removal. Under the special condition of complete spiral core unloading, it is expected that the count rate of the SRM's will drop below 3 cps before all of the fuel is unloaded.

Since there will be no reactivity additions, a lower number of counts will not present a hazard. When all of the fuel has been removed to the spent fuel storage pool, the SRM's will no longer be required. Requiring the SRM's to be operational prior to fuel removal assures that the SRM's are operable and can be relied on even when the count rate may go below 3 cps.

4 During spiral reload, SRM operability will be verified by using a portable external source every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> until the required amount of fuel is loaded to maintain 3 cps. As an alternative to the above, up to two fuel assemblies will be loaded in different cells containing control blades around each SRM to obtain the required 3 cps. Until these assemblies have been loaded, the 3 cps requirement is not necessary.

C. Spent Fuel Pool Water Level To assure that there is adequate water to shield and cool the irradiated fuel assemblies stored in the pool, a minimum pool water level is established. The minimum water level of 33 feet is er.tablished because it would be a significant change from the normal level (-l foot) and is well above the level to assure adequate cooling.

(During selected refueling outages, prior to initiating spiral unloading, the central controlled cell will be removed to facilitate inspection of the Core Spray Spargers.

Revision 99 204A