ML20207B449

Special Rept:On 880620,area Temp Inside RCS Pressurizer Cubicle Greater than 120 F.No Abnormal Trends Which Would Associate Cause of Temp Excursion to Leakage in Area.Revised Thermal Life Calculations Performed on Environ Equipment

ML20207B449
Person / Time
Site:	Millstone
Issue date:	07/19/1988
From:	Scace S NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
MP-12062, NUDOCS 8808020339
Download: ML20207B449 (2)

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HARTFORD. CONN ECTICUT 06141-0270 L L J CMCC.7C' (203) 665-5000 Docket No: 50-423  ;

Re: 10CFR50.36 U. S. Nuclear Regulatory Commission July 19, 1938 Attn: Document Control Desk MP-12062 Washington, DC 20555

REFERENCES:

(1) E. J. Mroczka Letter to U. S. Nuclear Regulatory Commission, Millstone Nuclear Power Station, Unit No. 3.

Proposed Revision to Technical Specifications Area Temperature Monitoring-Containmeg , dated June 21, 1988 Centlemen:

Millstone Nuclear Power Station, Unit No. 3 Area Teraperature Monitoring - Containment (CS-01)

This special report is being submitted within thirty days pursuant to Plant Technical Specifications 3.7.14b and 6.9.2. Plant Technical Specification 3.7.14b requires that a special report be submitted to the NRC within 30 days, if one of more area (s) exceeds the Containment Area CS-01 (inside crane wall) temperature limit of 120 degrees Fahrenheit, by less than 20 degrees and for a period greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. The specific area being discussed is the Pressurizer Cubicle, monitored by temperature element ECS-TE137.

On June 20, 1988 at 1837 hours0.0213 days <br />0.51 hours <br />0.00304 weeks <br />6.989785e-4 months <br />, with the plant in Mode 1 at 100% power, 2250 psia and 586 degrees Fahrenheit, temperature element ECS-TE137 in Contairaent Areas CS-01 indicated that the area temperature inside the Reactor Coolant System Pressurizer Cubicle was greater than 120 degrees for a duration greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Temperature element ECS-TE137 was monitored and verified less than 140 degrees - the temperature at which equipment in the area monitored by ECS-TE137 must be declared inoperable in accordance with the plant's Technical Specifications. At 2052 hours0.0238 days <br />0.57 hours <br />0.00339 weeks <br />7.80786e-4 months <br /> on June 23. ECS-TE137 indicated that the temperature inside the Pressurizer Cubicle went below 120 degrees. Total time of the temperature excursion was approximately 74 hours8.564815e-4 days <br />0.0206 hours <br />1.223545e-4 weeks <br />2.8157e-5 months <br />, with a maximum temperature of 123.3 degrees during the temperature excursion.

A review of Containment Dev Point temperatures as well as leakage detection system parameters revealed no abnormal trends which would associate the cause of the temperature excursion to leakage in the area. The temperature excursion above the Technical Specifications limit is attributed to normal operating temperature influences and the inherent design of the Pressurizer Cubicle. The temperature history of the Pressurizer Cubicle indicates that the cubicle temperature is expected to exceed its present plant Technical Specifications limit during normal power operation.

Revised thermal life calculations have been performed for the environmentally qualified equipment located inside the Pressurizer Cubicle for continued operation at a temperature of 130 degrees. The results of these calculations indicate no significant impact on the thermal life characteristics of this equipment as a result of the temperature excursion and demonstrate continued g operability of the associated equipment. f)i 0 8800020339 000719 PDR ADOCK 05000423 PNU g

On June 21, 1988, Northeast Nuclear Energy Company submitted a proposed license amendment to facility operating license NPF-49, by incorporating certain changes to the Millstone Unit No. 3 Technical Specifications Table 3.7-6 (Reference (1)). Specifically the proposed changes to Table 3.7-6 were submitted to create two new environmental zones, one of which is CS-03, Containment Area Pressurizer Cubicle and to raise the Maximum Normal Excursion (i.e. the Technical Specification) temperature limit from 120 degrees to 130 degrees. One of the reasons for the proposed license amendment is that ECS-TE137 monitors a specific well defined area, i.e. the Pressurizer Cubicle, which has indicated a higher normal maximum average temperature value than originally predicted for Containment Area CS-01. The qualified life for the environmentally qualified equipment inside the Pressurizer Cubicle has been recalculated based oc the requested Maximum Normal Excursion valce of 130 degrees Fahrenheit.

The following is a list of affected equipment for ECS-TE137 (Pressurizer Cubicle):

3RCS*MV8000A - Pressurizer Relief Isolation Valve 3RCS*MV8000B - Pressurizer Relief Isolation Valve 3RCS*PCV455A - Pressurizer Power Operated Relief Valve 3RCS*PCV456 - Pressurizer Power Operated Relief Valve 3RCS*SV8095A - Reactor Vessel Head Vent Isolation Valve 3RCS*SV8095B - Reactor Vessel Head Vent Isolation Valve 3RCS*SV8096A - Reactor Vessel Head Vent Isolation Valve 3RCS*SV8096B - Reactor Vessel Head Vent Isolation Valve Thirty days from receipt of the license amendment (Reference (1)), a special report will be submitted, if required, documenting all temperature excursions inside the Pressuricer Cubicle during the elapsed period. Temperature excursions will not be submitted individually as they occur, unless the temperature excursions exceed 130 degreec.

As additional information, Special Reports /LERs86-016 and 87-023 also document temperature excursions inside Containment Area CS-01 -

the Pres-surizer Cubicle, which have been attributed to the inherent design of the i Pressurizer Cubicle and to normal operating temperature influences.

This special report is being submitted pursuant to Plant Technical Specifications 3.7.14b and 6.9.2. The licensee contact for this special report is Vere Joseph, who may be contacted at (203)447-1791, ext. 5571.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY ,

I km en Step en E. Scace '

Station Superintendent Millstone Nuclear Power Station SES/VRJ ck cc: W. T. Russell, Region 1. Administrator D.11. Jaf fe, NRC Project Manager, Millstone Unit Nos. 2 and 3 W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 5

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