ML20196B796

CRD Partial Scram Test Results & Max Daily Temp Rept, 880117-31

ML20196B796
Person / Time
Site:	Fort Saint Vrain
Issue date:	01/31/1988
From:	Ronald Burrows, Novachek F PUBLIC SERVICE CO. OF COLORADO
To:	Calvo C NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation
References
P-88054, TAC-61601, NUDOCS 8802120147
Download: ML20196B796 (8)

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P-88054 Attachment 1 CONTROL R0D DRIVE PARTIAL SCRAM TEST RESULTS AND MAXIMUM DAILY TEMPERATURE REPORT REPORT PERIOD:

JANUARY 7, 1988 - JANUARY 31, 1988 Prepared by: 2 < u yf

'R. L. 66rrows Senior Plant Engineer Approved by: -

F. 'd./ Novabhek Technical / Administrative Services Manager Public Service Company of Colorado Fort St. Vrain Unit No. 1 8802120147 08020227 PDR ADOCK 050 P

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P-88054 Attachment 1 Page 1 I. ABSTRACT This report summarizes the partial scram test results and the maximum daily . temperature of those control rods with motor temperatures above 215' degrees Fahrenheit. It is prepared to satisfy the Fort St. Vrain Interim Technical Specification Surveillance Requirement 4.1.1.A.1.a. The time pericd covered by this report' is January 7,1988 through January 31, 1988.

II. BACKGROUND Because proper operation of the Control Rod Drive Mechanism (CRDM) is critical for safe operation of the reactor, a series of qualification tests were conducted over a one year time span to demonstrate its capability. The motor temperature during these tests varied between 200 degrees Fahrenheit and 230 degrees Fahrenheit, and averaged 215 degrees Fahrenheit. A total of 130,000 jog cycles plus 1600 scrams was logged during the fina?

design testing, which is many times that expected over the normal life of a CRDM. The operating temperature of the CRDM is limited by the motor's Class H insulation which is de-rated to 272 degrees Fahrenheit to account for motor temperature rise, frictional torque increase, and winding life expectancy.

In order to monitor CRDM temperatures, Resistance Temperature Devices (RTD's) are mounted on the closure plate, orifice valve motor plate, and CRDM motor as shown on Figure 1. All CRDM's installed in the reactor are equipped with RTD's. Three recorders located in the control room record each of these temperatures for all 37 CRDM's. CRDM motor temperatures are alarmed at 212 degrees Fahrenheit and 247 degrees Fahrenheit.

CRDM motor temperatures are monitored at least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to verify that they are less than 250 degrees Fahrenheit, which is a limiting condition for operation. If one or more CRDM motor temperature (s) is found to be greater than 215 degrees Fahrenheit during the daily surveillance, the motor temperature of all CRDM's exceeding 215 degrees Fahrenheit is recorded and a partial i scram test is performed on the CRDM with the highest motor temperature once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. These surveillances ensure that CRDM motor temperatures exceeding 215 degrees Fahrenheit do not degrade the CRDM's reliability to perform its design function when required.

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P-88054

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SUMMARY

OF RESULTS CRDM motor temperatures exceeded 215 degrees Fahrenheit for two intervals during this report period. -The .first interval' was from January 7,1988 through January 13,1988. The second-interval was from January 16, 1988 through January 31, 1988.

Since the daily scram surveillance is performed only when CRDM motor temperatures exceed 215 degrees Fahrenheit, data is presented for these two intervals only.

The partial scram test results and maximum daily temperature of those CRDM's with motor temperatures above 215 Ldegrees Fahrenheit are presented on Table 1. The pertinent-parameters presented are: reactor region involved, control rod porition, maximum daily motor temperature, extrapolated scram times (surveillance value and Back EMF calculated value) and starting acceleration. -The control rod position is presented because of its relationship to available starting torque which affects the starting acceleration and extrapolated. scram time.

calculated by surveillance. The surveillance extrapolated scram . time is affected by control rod position because it is calculated using distance travelled versus time. . Since the acceleration is slower at lower control rod positions, a longer period of time is required to reach steady state speed.

This longer acceleration period results_in a decrease in distance travelled over a_given period of time, and thereby indicating a longer extrapolated scram time. The extrapolated scram time calculated by the Back EMF program applies a correction factor to provide a projected full length scram time. Therefore, the surveillance scram times can only be compared for trends if the control rod position is approximately the same. .The Back EMF calculated scram time is more readily trended since the value should be independent of control rod position.

The starting acceleration values presented represent those calculated by the Back EMF program. These values reflect the CRDM's freedom of rotation to accelerate to steady state speed and therefore are considered to be valuable performance indicators. Two values are presented: The actual acceleration measured during a scram from the indicated control rod position, and the projected acceleration if the control rods were at the full out position (greater than 188 inches). If the control rod position is greater than 188 inches, no data is presented for a projected starting acceleration since the actual and projected are the same. As indicated with scram times, the projected starting acceleration is more readily trended since the value should be independent of control rod position.

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'i; Attachment 1 l' Page 3' IV.. CONCLUSIONS The performance of CRDM's with motor.. temperatures in excess of

~ -215 degrees Fahrenheit did not show any significant tr.nds or degradation during this report period. .Therefore, it is concluded that CRDM motor temperatures excee' ding- 215 degrees '

Fahrenheit did .not degrade the CRDM's reliability to perform' its design function when required.

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. Attachment 1

' TABLE 1 Control Rod Extrapolated Scram ' Sta rting Accolarat eon ~

Oate Region

• Position (in.) Maximum Motor Te Daily 9 ( ,F) Tiue (Sec)** (Rad /Sec/Sec)***

Jury. Back EMr Actual Pro.fected ja 1-07-88 12 84.4 242.1 1ba.0 N/A**** N/A**** N/A**** Li; 1-08-88 12 102.7 28.4. 6 140.6 145.1 '106.3 117.0 30 N/A 216.4 N/A N/A N/A N/A 1-09-88 12 107.6 245.4 142.0 145.0 108.5 116.6 '

30 N/A 216.4 N/A N/A N/A N/A 1-10-88 12 109.9_ 237.1 143.2 lb5.1 108.5 116.4 26 N/A 216.6 N/A N/A N/A ' N/A 1-11-83 12 111.5 237.0 140.8 145.1 109.5 117.2 26 N/A 21C.5 N/A N/% N/A N/A 1-12-88 12 120.0 240.6 148.4 146.1 109.5 116.2 26 N/A 219.0 N/A N/A N/A N/A 1-13-88 12 123.1 240.2 -134.8 145.1 108.9 115.2 26 N/A 217.6 N/A N/A N/A N/A 1-14-88 Sircugh 1-15-89 Ne da ta presented. All CRDM rotor ter6,eratures less than 215 degrees Fahrenheit.

1-16-88 12 123.3 240.0 140.4 145.1 113.7 118.1 26 N/A 215.0 N/A N/A N/A N/A 1-17-88 12 145.0 233.2 149.6 145.2- 111.8 116.3-1-18-88 12 154.8 226.0 136.7 145.0 111.9 115.3 1-19-88 12 178.0 225.9 148.4 145.1 113.4 116.5 1-20-88 12 162.0 22'i.9 152.0 145.2 113.0 115.5 1-21-88 12 100.4 230.4 138.7 144.7 107.9 116.8 ~

1-22-88 12 113.3 220.4 140.9 145.1 1G8.4. 115.9 1-23-88 12 162.0 233.1 15c.8 145.2 113.2 -115.7 1-24-88 12 176.1 231.5- 138.6 145.1 114.4 115.9 1-25-88 12 187.0 230.2 122.6 145.2 115.3 115.6 1-26-88 12 180.4 224.4 140.1 145.1 114.1 115.2 1-27-88 12 189.9 224.1 147.3 143.7 116.2~ N/A i

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' Attrichment 1 TA8tE 1' ,

Control Rod Extrapolated Scram Starting AcceIsratIon Date Reglon* Position (in.) Maximum Daiiy*F)

Motor Temp. ( TIES (Sec)** -(Rad /Sec/Sec)***

Sury. Pack EMF .Actuaf PmiecM 1-28-88 12 189.8 222.1 138.3 1883. 8 117.1 ' N/A 1-29-88 12 189.8 222.2 138.3 143.7 116.3 N/A 1-30-88 12 189.9 236.4 148.4 143.9 115.2 N/A 30 N/A 215.6 N/A - N/A N/A N/A 1-31-88 12 189.9 232.6 149.6 143.8 116.4 N/A 30 N/A 216.8 N/A N/A N/A N/A

• Region with highest CROM motor temperature listed fi rst.

• t_ i m i t i ng Co nd i t i on fo r ope ra t i on : .(152 sec.

• • • Acceptance criteria applied during preventive maintenance: $8.83 Rad /Sec/Sec.

• • • • 8ack LMF data for 1-7-88 not ava ilable, s

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16805 WCR 19 1/2, Platteville, Colorado 80651 February 2, 1988 Fort St. Vrain Unit No. 1 P-88054 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Attention: Mr. Jose A. Calvo Director, Project Directorate IV Docket No. 50-267

SUBJECT:

CONTROL RDD DRIVE PARTIAL SCRAM TEST RESULTS AND MAXIMUM DAILY TEMPERATURE REPORT

Dear Mr. Calvo:

The Fort St. Vrain Interim Technical Specifications (Surveillance Requirements, Section 4.1.1.A.1.a) require that a report be provided to the NRC at least once every 31 days when one or more Control Rod Drive (CRD) motor temperature (s) exceeds 215 degrees Fahrenheit. A report on the partial scram test results and the maximum daily temperature of those CRD's with motor temperatures above 215 degrees Fahrenheit is included as Attachment 1 for your review.

We hope you will find this submittal responsive to your concerns. If you have any questions or comments, pleas- contact Mr. M. H. Holmes at (303) 480-6960.

Sincerely,

$/W R. O. Williams Vice President Nuclear Operations R0W:RLB/bj Attachment cc: Regional Ad.ninistrator, Region IV Attention: Mr. T. F. Westerman, Chief Project Section B cc: Mr. R. E. Farrell Ago/

Senior Resident Inspector l Fort St. Vrain f