IR 05000277/1978029
| ML19305A172 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/22/1978 |
| From: | Greenman E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19305A167 | List: |
| References | |
| 50-277-78-29, 50-278-78-32, NUDOCS 7901040322 | |
| Download: ML19305A172 (10) | |
Text
U.S. NUCLEAR REGULATORY COMMISSION
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OFFICE OF INSPECTION AND ENFORCEMENT Region I
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50-277/78-29 Report No.
50-278/78-32 50-277 Docket No.
50-278 DPR-44 C
License No. nPR-56 Priority
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Category C
Licensee:
Philadninhia Floctric Comoany 2301 Market Street Philadelohia. Pennsylvania 19101
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Facility Name:
Peach Bottom Atomic Power Station, Units 2 and 3 Inspection at:
Delta, Pennsylvania Inspection conducted: October 30-November 3,1978 Inspectors:
[de 8>f
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E. G. Greenman, Reactor Inspector dat3 signed t
date signed date signed i
Approved by:
c'O b 01 )v ii /n l is E. C. McCabe, Jr., Reactor Projects Section date sigred No. 2, RO&NS Branch Inspection Summary:
Inspection on October 30-November 3, 1978 (Recort No. 50-277/78-29 and 50-278/78-32)
Areas Inspected:
Routine, unannounced inspection by an NRC regional based inspector of plant operations including facility tours and survey measure-ments, licensee event report review (in-o#fice and :nsite), shock suppressors,
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monthly operations reports review and inde. pendent erfort.
Ine inspection in-volved 17.5 inspector-hours onsite at Unit 2 and 17.5 inspector-hours onsite at Unit 3 by one NRC regional inspector.
Results:
One item of noncompliance was identified (Infraction - Failure to maintain a High Radiation Area door in a locked condition at Unit 3 - Detail 3).
Region I Form 12 7901040372 (Rev. April 77)
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conditions.
The inspector checked equipment status and operability and verified by comparison of selected control room instrumentation and in-plant instrumentation that limiting conditions for operation were being satisfied. The status of off-normal alarms were dis-cussed with various operating personnel.
Operators were knowledge-able of plant conditions. Minimum staffing requirements were also verified based on control room observations.
Radiation surveys were made.
No unacceptable conditions were identified.
During the conduct of facility tours, numerous doors requiring locking were checked..No unacceptable conditions were identified at Unit 2.
Inspection determined at Unit 3,135 feet elevation, in the Turbine Building that the 3B and 4B FWH room door (a designated High Radiation Area) was closed but that the lock was not functional in that the door could be and was opened by the inspector.
This was contrary to Technical Specification 6.13.1.b which requires areas in which the intensity of radiation is greater than 1000 millirem /hr. to be provided with locked doors to prevent unauthorized entry and constitutes an Infrection level item of noncompliance (78-32-01).
The inspector also reviewed a current radiation survey for the area dated October 31, 1978 which indicated total radiation levels of various areas within the rcom varying from 12-1200 milli-rem / hour. The licensee took prompt and timely corrective action including door adjustments and this action was reviewed by the inspector as well as corrective action to preclude recurrence of what was con'sidered to be an isolated instance.
Conseqtantly no additional response is required with respect to this mat.er.
The inspector also reviewed High Radiation Lock Surveys to determine that the licensee's audit function was in place.
No additional unacceptable findings resulted.
4.
Results of Snubber Inspections (Unit 2)
a.
Visual Inspection At the beginning of the refueling outage which commenced September 9,1978, a visual snubber inspection was conducted as required by T.S.
This inspection identified nine hydraulic snubbers with empty resevoirs. These snubbers were removed and tested to determine if the visual inspection showing no fluid level also indicated inoperability.
The following 3 of 9 snubbers tested based upon visual results evidenced charac-teristics outside the acceptable limits.
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DETAILS 1.
Persons Contacted C. E. Anderson, Operations Engineer J. Davenport, I&C Engineer S. Roberts, Results Engineer J. Spencer, Maintenance Engineer
- W. Ullrich, Plant Superintendent A. hasong, Test Engineer Other licensee employees were contacted during the inspection.
These included engineering personnel, administrative personnel, reactor operators, shift supervision, security personnel and health physics personnel.
- denotes those present at management meetings.
2.
Logs and Records The following logs and records were reviewed for the periods as indicated.
Comments concerning specific areas are contained within this report.
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a.
Shift Supervision Log, October 1-November 2,1978.
b.
Plant RWPs (Radiation Work Permits) - Sampling.
c.
Snubber Test Records - Unit 2 1978 outage.
d.
Radiation - Contamination Survey Results (Sampling).
e.
Rad Lock Surveys - Sampling, f.
PORC Meeting Minutes 78-83-3, 4 and 5.
3.
Facility Tour Facility tours were conducted at both Unit 2 and Unit 3 on numerous occasions during the course of this inspection. Areas examined in-cluded the turbine building, reactor building, control room and exterior areas including access controls.
Inspections were con-ducted to detennine the general state of cleanliness, housekeeping, adherence to fire protection guidelines and to observe plant i
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(1) Snubber 23HB-S-38. indicated a bleed velocity of.088"/
minute in tension. Minimum acceptable bleed rate is 1/8"/ minute and the snubber was declared inoperable.
(2) Snubber 1-66-S-75 indicated a locking velocity of 13.7"/
minute in tension. Minimum acceptable locking velocity for this snubber is 14"/ minute.
The licensees review based on as left data from the last inspection showed that this snubt - had been incorrectly set at a locking velocity of 10+1"/ minute.
The licensees review further indicated this failure to be administrative in nature and not related to deterioration or any mechanical nature therefore the snubber was not declared inoperable.
(3) Snubber SS-136 exhibited an average bleed velocity in compression of 11.1"/ minute which was in excess of the original acceptable maximum bleed rate of 10"/ minute.
The inspector reviewed ITT Grinnell Technical Report PHD 7579-S-1 dated October,1977 entitled, "A Parametric Study of the Effect of Locking Velocity and Bleed Rate Setting on the Dynamic Perfonnance of ITT Grinnell Figure 200 and Figure 201 Hydraulic Snubbers".
The report in-dicated findings based upon testing of a 21/2 inch bore snubber where in one series of tests the locking velocity was held constant and the bleed rate was varied over a wide range and in another series the bleed rate was held constant while velocity was varied.
Sinusoidal displace-ment at different frequencies was used as the controlled dynamic input.
The report stated that for the range of locking velocity from 1.0 inches / minute to 40 inches / minute and the range of bleed rate from 0.1 inches / minute to 25 inches / minute the dynamic response of the snubber was not significantly different from the response at the factory settings of 8 inches per minute for locking velocity and 4 inches / minute for bleed rate.
Grinnell concluded that the response of ITT Grinnell Figure 200 or 201 snubbers to an arbitrary dynamic loading with a locking velocity and bleed rate in the above range would be essentially the same as the response at the factory settings.
Utilizing the Grinnell data and conclusions, the snubber was not considered to be inoperable.
Based upon the above, with one snubber inoperable, T.S. 4.11.D.1 specifies an inspection frequency of 12 months + 3 months.
The inspector had no further questions concerning visual
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inspection results and the licensees compliance with T.S.
4. ll.D. l.
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i The licensees review of Snubber 1GG-S-75 indicated that incorrect criteria was used to set 8 snubbers in 1977 (Last previous outage).
Of these eight, only 4 were in a nonconservative direction and no additional snubbers failed to meet acceptance criteria.
b.
Functional Testing
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In accordance with T.S. 4.ll.D.4, ten snubbers were also selected and removed from their locations and then function-ally tested. One of the ten units was later identified as having an empty reservoir and is included under the visual inspection discussed previously.
Of these 10 units, two had bleed rates in tension of less than 1/8"/ minute.
An addi-tional 2 units showed locking velocities less than the 14"/ minute acceptable value.
T.S. 4.ll.D.4 requires 10 additional units to be tested for each failure.
Based on these findings, the licensee elected to remove all (145) safety related snubbers and functionally test entirely.
Breakdowns concerning functional testing results are summarized below:
(1) Operational Criteria (14"-30" per minute locking velocity and bleed rate 1/8"-10"/ minute)
(a) Relief Valve Line Snubbers *
Total snubbers *
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Number of snubbers tested as found
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Number of Snubbers whose average
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locki.ng velocity did not meet acceptance criteria
Number of snubbers whose average
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locking velocity did not meet acceptance criteria or had one or more locking velocity readings below acceptance criteria
Number of snubbers with average
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bleed rate <1/8"/ min.
- Data not obtained for as found condition.
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Number of snubbers with average
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bleed rate <l/8"/ min. or one bleed reading <1/8"/ minute
Number of snubbers previously
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calibrated in nonconservative direction
(b) All Other Safety Related Snubbers (6"-30" per minute locking velocity and bleed rate 1/8"-10"/
minute)
Total snubbers *
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Number of snubbers tested as found
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Number of snubbers whose average
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locking velocity did not meet acceptance criteria
Number of snubbers whose average lock-
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ing velocity did not meet acceptance criteria or who had one or more locking velocity readings below acceptance criteria
Number of snubbers that did not
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meet original 9"-30" acceptance criteria
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Number of snubbers with average bleed rate <1/8"/ minute
Number of snubbers previously mis-
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calibrated in conservative direction
(2)
Location (a) Drywell Total snubbers 107
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Number tested as found (see footnote
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for previous table)'
103
- Data not obtained for as found conditio.
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Number of snubbers with average
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locking velocity below acceptance criteria
Number of snubbers with locking
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velocity acceptance criteria of 14"-30"/ minute
Number of snubbers (14"-30" acceptance
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criteria) with low average locking velocity
Number of snubbers with locking
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velocity acceptance criteria of 6"-30"/ minute
Number of snubbers (6"-30" acceptance
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criteria) with low average locking velocity
Total number of 6"-30"/ minute locking
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velocity snubbers which would have been considered failures at original 9"/ minute lower limit
Number of snubbers with bleed rates
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less than 1/8"/ minute
(b) Outside Drywell (All snubbers have locking velocity acceptance criteria of 6"-30"/ minute)
Total number of snubbers
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Number tested as found
Number of snubbers with average lock-
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ing velocity below acceptance criteria
Number of snubbers which would have
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been considered failures at original 9"/ minute lower limit
Number of snubbers with bleed rate of
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<1/8"/ minute
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c.
Low Bleed Rate - Causative Mechanism Dismantling of several snubbers indicated that the cause of the low bleed velocity was foreign material in the hydraulic fluid capable of plugging orifices in the snubber valve block.
Oil sample analysis indicated that the material appeared to be
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flakes of ethelene propylene which apparently entered the hydraulic system during installation of the valve block bleed rate adjustment screw.
If the EP seal washer was not threaded onto the screw small flakes could become lodged in the thread and eventually fall into the block during assembly. All snubbers exhibiting low bleed rates were dismantled, rebuilt fd retested and calibrated.
The inspector reviewed Procedure M18.1 Revision 6, dated September 30, 1978, " Hydraulic Snubber Overhaul" and confirmed that procedural requirements have been established for threading the EP thread seal on the adjustment screw to preclude this problem.
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d.
Low Locking Velocity - Causative Mechanism The Grinnell report PHD 7579-S-1 review indicated that velocity is adjusted by varying compression in the snubber spring loaded poppet arrangement.
Thus for a given setting of the spring, the locking velocity is dependent upon the viscosity of the hydraulic fluid which varies significantly with temperature.
Verification testing performed by the licensee and reviewed by the inspector indicated a temperature sensitivity with re-spect to locking velocity of nominally 0.4 inches per minute per degree F*.
The data obtained during functional testing showed locking velocities of 2 inches to 4 inches per minute less than velocities as set during previous outages such that a variation of 10'F in ambient conditions could account for the variations found.
No data was available to substan-tiate snubber test area temperatures during prior outages.
The licensee is continuing to evaluate new data from the manu-facture relating to the locking velocity relationship to tem-perature.
This area is also currently under review by NRC
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management. The licensees engineering evaluation confirmed snubber operability at elevated temperatures.
Discussion with a cognizant licensee representative that applicable procedural revision will be made to reflect those engineering
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reviews and the new acceptance criteria prior to the next functional testing.
This item is unresolved pending revision to these procedures (78-29-01 and 78-32-02). The licensee also comitted to functionally test 10 representative snubbers
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l between three and nine months from the Unit 2 startup to provide further assurance that the snubbers are fully oper-able during the operating cycle. A future inspection will be conducted to confirm function testing results (78-29-02).
All snubbers at Unit 2 were recalibrated to lockup at 20+2
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inches per minute and all bleed rates were set at 3-5 inches per minute.
5.
Inoffice Review of Monthly Operating Reports The following licensee reports have been reviewed inoffice.
Peach Bottom Atomic Power Station Monthly Operating Reports for:
a.
August 1978 dated September 15, 1978.
b.
September 1978 dated October 15, 1978.
These reports were reviewed pursuant to Technical Specifications and verified to determine that Operating Statistics included shutdowns and that narrative summaries of the months operating experience were contained therein.
No unacceptable conditions i
were identified.
6.
Nonroutine Event Review The inspector reviewed the following nonroutine events both in-office and onsite for safety significance, circumstances and re-lationship to Technical Specification protective limits. The licensees PORC review, evaluation and corrective action was also verified.
LER Number 2-78-35/3L
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E-3 D.G. start time to reach rated voltage and frequency did not meet surveillance re-quirement due to a leaking check valve in the hydraulic system.
2-78-41/1T
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4 KV emergency bus sequentia loading re-lays were found set outside talibration range.
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2-78-42/3L
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Inboard Mainsteam Line Drain Isolation Valve failed to close electrically.
3-78-16/3L
"D" Mainsteam Line Radiation Monitor failed
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to cause a half scram during surveillance testing.
7.
Unresolved Items Unresolved Items are those for which more information is needed to verify acceptability. Detail 4 contains an unresolved item.
8.
Exit Interviews At periodic intervals during the course of this inspection, meet-ings were held with facility senior management (denoted in Para-graph 1) to discuss inspection scope and findings.
Licensee representatives acknowledged inspection findings.