IR 05000271/1979007
| ML19247B737 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/19/1979 |
| From: | Bettenhausen L, Caphton D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19247B735 | List: |
| References | |
| 50-271-79-07, 50-271-79-7, NUDOCS 7908130291 | |
| Download: ML19247B737 (6) | |
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U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION A1T ENFORCEMENT
REGION I
Report No. 50-271/79-07 Docket No. 50-271 License No. DPR-28 Priority --
Category C Licensee:
Vermont Yankee Nuclear Power Corp.
20 Turnpike Road Westborough, MA 01581 Facility Name: Vermont Yankee Nuclear Power Station Inspection At: Vernon, Vermont Inspection Conducted:
May 1-3, 1979 (AW[f Inspector:
A L. H. Bettenhausen, Reactor Inspector Date Signed
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Approved By:
D. L. Caphton, Chief, Nuclear Da'te Signed Support Section No.
1, RO&NS Branch Inspection Summary:
Inspection on May 1-3, 1979 (Report No. 50-271/79-07)
Areas Inspected:
Routine, unannounced inspection of startup testing program following fuel shuffling covering areas of control rod scram times, sequences and reactivity checks; core power distribution; calibration of local and average power ran._ monitors; core thermal power evaluation; and determination of reactor shutdown margin and
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reactivity anomalies.
The inspection involved 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> onsite by one NRC regional based inspector.
Noncompliances: None.
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DETAILS 1.
Persons Contacted B. Buteau, Reactor Engineering Assistant
- W.
Conway, Plant Superintendent P. Donnelly, I&C Supervisor
- D.
Girroir, Engineering Assistant W. Murphy, Assistant Plant Superintendent
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- L. Rau_, Reactor Engineer G. Wallin, Records Clerk
- Denotes those present at the exit interview of May 3, 1979.
2.
Licensee Action on Previous Inspection Items (Closed) Unresolved Item (271/79-04-01):
Training sessions were conducted between March 19 and 23, 1979 for licensed operators; these sessions included operators' obligation to maintain line of sight with panels in the control. room with negative emphasis on " partially" leaving the line-of-sight area.
Pro-cedure A.P. 0150, Responsibilities and Authorities of Operations Department Personnel, was issued as Revision 10 on April 12, 1979 to include clarification of the line-of-sight control room area.
This matter is considered to be resolved.
(Closed) Unresolved Item (271/79-06-01):
The inspector reviewed veddor and corporate safety evaluations and the draft minutes of Plant Operations Review Committee (PORC) meetings 79-17 and 79-18 held April 2 and 3, 1979 to consider full power operation for cycle 6A where 84 previously exposed 8D219 fuel bundles replaced 8D274 fuel bundles known or suspected of leaking.
The conclusion of these analyses was that all requirements of 10 CFR 50.59 were met for the reconfigured core so that the plant could operate at all power levels within current Technical Specificaticns.
The inspector had no further questions and this matter is considered to be resolved.
3.
Post-Refueling Startuo Testing The inspector reviewed the following tests and checks to verify that the startup for Cycle 6A following the partial refueling of March, 1979 was conducted in accordance with technically adequate plant procedures.
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Control Rod Scram Insertion Times.
The inspector reviewed test data for Scram #88 whereby all rods were scrammed
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and timed in single rod tests under Procedure 0.P. 4424,
Control Rod Scram Testing, Rev. 4, dated December 6, 1977 on April 1 and 2, 1979.
The test results can be su=marized as follows:
Nominal Average Times Technical
% Inserted Scram #88 Specifications 90%
2.460 (sec)
3.419 (sec)
46%
1.365 1.860 25%
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0.838 1.096 5%
0.325 0.358 b.
Control Rod Sequence and Reactivity Checks.
The licensee uses procedure 0.P. 4450, Rod Worth Minimizer Surveillance and Shutdown Margin Checks, Rev. 3, dated January 17, 1978 to document the correct loading of the Rod Worth Minimizer (RWM) program for the rod withdrawal sequences specified and to verify the program by operator selection of out-of-sequence rods and RWM function to prevent withdrawal.
In addition, shutdown margin is checked by withdrawing operable edge rods to predetermined notch positions and verifying suberiticality.
The procedure was performed satisfactorily on March 31, 1979.
c.
Core Power Distribution Limits.
Daily surveillance of core thermal hydraulic limit.s as required by Technical Specification 4.11 is performad under Procedure 0.P. 4401, Core Thermal Hydraulic Limits ' Evaluation, Rev. 6, dated February 22, 1979.
The procedure requires operater review of computer calculations for maximum peaking factor, maxi-mum average planar linear heat generation rate, minimum critical power ratio, and fraction of limiting core power
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density.
The inspector reviewed completed data sheets for the period April 4, 1979 through April 30, '079 and compared data sheets with associated computer edits P1, OD-6, options 3 and 4 and OD-59, option 32 at random to verify performance of the surveillance and compliance with Technical Specifications.
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-4-In addition, the inspector observed the perfor=ance of Calibration #403 on May 2, 1979.
This calibration is done by running a complete set of Traversing Incore Probe (TIP) data under control of the OD-1 computer program as specified in 0 P. 2425, Core Power Distribution Calculation, Rev. 4, February 22, 1979.
A satisfactory calibration was completed about 3:30 p.m.
A calibration begun earlier in the afternoon was unsatisfactory because of erroneous computer data entries resulting from concurrent maintenance on an APRM recorder.
d.
Local Power Range Monitor (LPRM) Calibration.
The inspector examined LPRM calibrations performed on March 8, 1979 and April 12, 1979 in accordance with procedure 0.P. 4406, LPRM Calibration and Functional Check, Rev. 2, Cetober 20, 1977.
Calibrations #391 and #400 were performed with technically adequate procedures and in accordance with Technical Specifications.
The licensee uses computer edits P-1 and OD-10, options 1, 7, 9, 11 and 13 before
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and after a full-core TIP set to verify as-left LPRM gain settings.
LPRM readings before and af ter calibration are plotted directly on the appropriate TIP trace as a further verification.
e.
Average Power Range Monitor (APRM) Calibration.
Thit calibration is done in accordance with procedure 0.P. 4400, Calibration of the Average Power Range Monitoring System to Core Thermal Power, Rev. 5, August 17, 1977.
The inspector reviewed data sheets for calibrations performed
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on April 4, 5, 6, 7. 9, 13, 16, 18, 20, 23 and 27, 1979 and compared data against computer edits OD-3 and P-1 for appropriate times to verify compliance with procedure and Technical Specifications.
f.
Core Thermal Power Evaluation.
The inspector reviewed the evaluation of core thermal power performed by procedure 0.P. 2411, Core Thermal Power (TSS'), Rev. 4, July 13, 1978 on April 4, 1979 at 0442.
The procedure utilizes console readings entered onto a data sheet and thence into a time-share off-site computer program.
This is compared to an OD-3 process computer calculation.
The inspector verified the physical properties and parameters used in the core thermal power evaluation and independently calculated similar results, b.30@7h
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Shutdown Reactivity Monitoring and Reactivity Anomalies.
Several checks and tests are performed to demonstrate adequate control of reactivity.
One performed during startup following refueling demonstrates adequate shut-
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down margin with the highest worth operable control rod fully withdrawn.
Procedure 0.P. 4426, Shutdown Margin Check, Rev. 6, February 9,1979, was performed on March 31, 1979.
Rod 22-39 was identified by the vendor s
to be the most reactive rod for the loading of Cycle 6A.
It was fully withdrawn.
Rod 18-35, selected as the margin rod, was analytically evaluated to be worth 0.73% at notch position 10 and 1.42% fully withdrawn; it was withdrawn first to notch 10 and then to notch 48, thereby demon-strating shutdown er.rgin in excess of the 0.61% required.
The rod reactivity worths were documented in memo NEX 79-96 transmitted from the fuel vendor on May 2, 1979.
Another check conpares actual critical rod pattern with predicted critical rod pattern and patterns for i 1% Ah-about the predicted critical.
This check was documented as part of procedure 0.P. 4430, Reactivity Anomalies, Rev. 4, December 1, 1978.
Data sheet VYOPF 4430.02 compares actual and predicted rod patterns in graphic form; the actual critical rod pattern for cycle 6A was within 2 cod notches of the predicted pattern and well
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within the i 1%t)tenvelope.
A third check in this area is the surveillance on reactivity anomaly, also performed as part of procedure 0.P. 4430.
This compares actual rod notch inventory of reactivity with predicted rod notch inventory and beunds of i 1%dh,within predictions.
Surveillance for reccti-vity anomalies in Cycle 6 was performed November 17, 1978, December 14, 1978, January 11, 1979, January 31, 1979 and March 1 1979; surveillance for Cycle 6A was first performed April 19, 1979.
All comparisons of actual and predicted rod notch inventories were well within the i 1% 2h EA requirement.
The inspector independently verified data and calculations.
No items of noncompliance or deviati;ns were identified.
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Lxit Interviev The inspector =et with licensee representatives (denoted in Paragraph 1)
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at the conclusion of the inspection on May 3,1979. The inspector
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summarized the scope and findings of the inspection as they are detailed
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in this report.
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