IR 05000029/1990011
| ML20058P076 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 08/01/1990 |
| From: | Chaudhary S, Lohmeier A, Terao D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20058P074 | List: |
| References | |
| 50-029-90-11, 50-29-90-11, NUDOCS 9008160031 | |
| Download: ML20058P076 (8) | |
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t UNITED STATES NUCLEAR REGULATORY COMMISSION
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REGION I
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Report No-90-11 Docket No.50-029
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License No. DPR-3-
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Licensee: Yankee Atomic-Electric Company 580 Main Street Bolton, Massachusetts 01740-1398
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Facility:Name;' ' Yankee Rowe Plant'
Inspection at:
Rowe, Massachusetts Inspection Dates: June 19-22, 1990
~ Inspectors:.
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C C. ChaudtrJrP~ Sr. Refactor Engineer, Materials da'te
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and Processes Section,' EB, DRS 2 10- 90
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'A. Lohmeier, Reactor Engineer, Materials and dat4 Processes Section, EB, DRS
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~!~ N Approved by:
.0. Terao,. Acting Chief, Materials and date
Processes ~Section, Engineering Branch,.DRS Inspection Summary:
Inspection June 19-22,1990 (Report 'No. - 50-029/90-11)
Areas Inspected:.The inspectors performed a routine inspection of the safety
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injection tank design and replacement procedures together with a walk-down of safety injection system pumps, valves and piping.
Maintenance of-Fatigue Cycle Operation Logs were reviewed and follow-up actions on previous inspection open items were reviewed.'
Results: 'No violations'or deviations were identified. As a result of the
inspection; one open item (50-02.9/90-04-01) remained unresolved and one open item (50-029/90-03-01) was cicsed.
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9008160031 900609 ADOCK0500g9 FDR
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DETAILS
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t 1.0 Persons Contacted Yankee Atomic Electric Company YNSD - Yankae Nuclear Service Division YNPS - Yankee Nuclear Power Station
- L. X. Bozek,-Quality Assurance Supervisor, YNSD
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- M. W. Fethersten, Maintenance Engineer, YNPS
- T. Henderson, Acting Plant Superintendent, YNPS.
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W.-Jones, Engineering Manager, YNSD
- K. E. Jurentkuft, Plant Operations Manager, YNPS.
- J. Kay, Technical. Services Manager, YNPS
- 0. King, Maintenance Support Supervisor,.YNPS C. D. Melin, Construction Engineer, YNPS R. Mellor, Technical Director, YNPS
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- R. M Mitchell, Maintenance Manager, YNPS
- N St. Laurent, Acting Manager of Operations, YNPS
United States Nuclear Regulatory Commission (USNRC)
- T. Koshy, Sr. Resident inspector, Yankee Rowe
- L Mayer, Reactor Engineer
- M. Markley, Resident Inspector, Yankee Rowe
- Denotes those attending the exit meeting on June 22, 1990,
The inspectors also contacted administrative and technical personnel during the inspection, 2.0 Scope of Inspection A routine unannounced inspection was conducted at the Yankee Electric Company Nuclear Power Generation Station in Rowe, Massachusetts during
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g the period June 19-22, 1990. The scope of the inspection-included review l-of design activities and fabrication procedures for the replacement safety injection tank together with a-walk-down of safety injection system
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pumps, valves and piping. The inspectors also witnessed a'part of the tank fabrication and erection activities.
Maintenance of fatigue cycle operation records and follow-up actions on previous inspection open. items were also reviewed, i
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3.0 Replacement Safety Injection Tank'(SIT)
't After a history of shell wall crack formation, propagation, leakage anc repair, the licensee made a decision to replace the-SIT (TK-28)-with a stainless steel tank.
The licensee. indicated that although the cracks
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had been evaluated and determined to be non propagating, there was evidence that the tank had been undergoing'long term deterioration.
Henca, in view of this continuing deterioration, the licensee determined that to ensure the continued reliability of the safety injection: system (SIS), it would.
be prudent to replace, rather than continue.to repair the original SIT.
The original tank will remain in service u'ntil the ~1990 refueling outage scheduled to begin approximately June 23, 1990.
During the outage, it will be drained and its piping connections cut and capped.
The replacement tank will be connected to the SIS. and the contents of the
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original tank pumped back from the refueling cavity.
Because the SIS.is not required by the Technical Specifications, the switch-over.will take place while the tank. inventory is in the refueling cavity.
Documentation of the SIT replacement is provided in EDCR 90-301.
The inspectors determined that the replacement tank-design has been verified for acceptability in accordance with ASME Section XI,.IWA 7220.
It is being fabricated on site from 304L stainless steel plate, chosen for its superior corrosion resistance and weldability.
The purpose of the new tank is solely to replace the original tank and is not intended to provide any new or additional capability to the plant.
The new tank is 30 feet in diameter with 32 feet shell height.
It has a flat bottom.and a domed
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roof. The tank capacity has a useable volume of'160,000 gallons.
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some additional design improvements have been incorporated, such as a 4.
inch supporting sand bed with stainless steel telltale drains resting on
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an 18 inch thick concrete slab over an octagonal. ring beam.
Improvements have also been made in instrumentation, tank insulation, valves, grounding, security lighting, ard tank access.
New engineered. safety considerations =
include seismic evaluation including the effect of " sloshing" and tornado missile damage.
Testing of -the tank includes ~ utilization of a vacuum box to test local sections of weldments and a standing water hydrostatic
pressure test to assure leak tightness of welded joints after the fabrica-
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tion process.
The tank was -designed by the Yankee Project Department including Mechanical Engineering, Systems Engineering, Electrical Engineering and Instrumentation and Control Engineering.
The design procedure was developed in.accordance l,
with the Yankee Atomic Electric Company QA and Engineering Manuals and included procedures for performing calculation _s by engineers, line-by-line-calculation checks and calculation approvals by the task group..The 1 eensee reviewed the final. design for adequacy and acceptability before
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tank erection.
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' A project team covering the mechanical,; systems, instrumentation and-controls, and electrical engineering ~was formed at the licensee's corporate
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headquarters, and a-project manager was appointed a the plant site.
The-team meets weekly at headquarters.
The construction' department which
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supervises the independent contractors:also participates.
For QC represen-tation at the plant site, an outside inspector has been retained by the plant site organization.
Selection'of the SIT fabricator by the project team ~and procurement personnel was based on the review of vendor. qualifi--
cations and bidding.
The YAEC report EDCR 90-301 includes a. safety evaluation _as required by:
-l 10_CFR 50.59 which describes the, function and design basis for the_ SIT; j
The EDCR document indicates that-the design-changes.in the replacement SIT..
l are expected to have minimal impact on the normal operation of the ECCS i
system, and no adverse impact during~ emergency conditions.
The replace--
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ment SIT is expected to substantially outperform the original SIT during
design basis events such as earthquakes and-tornadoes. With the replacement j
SIT, the licensee concluded-that there will be no increase in the. con-sequences of an accident previously' evaluated in the FSAR the probability
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of malfunction of equipment important to safety is not increased, the possibility for creation of a new type of unanalyzed event different than those considered in the FSAR will not be created by-the replacement SIT, and the margin of safety will not be reduced, therefore,, permitting _
l replacement under 10 CFR 50.59 rules.
l a-l 4.0 Replacement Safety Injection Tank Construction j
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The inspectors observed the construction of the replacement SIT which
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was in the process of being fabricated.
The concrete and sand support
structure was complete and the bottom flat plate (s) were in position.
The plates for the vertical cylindrical portion of: the SIT were all tack welded l
in position, and a large portion of the welding-of these plates together..
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had been completed. Welding of the dome conical section was in progress-
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with some of the dome plate yet to be formed.
Many of' the fittings and
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connections were also welded to the cylindrical shell portion.
After-l grinding smooth to the shell surface, the welds were visually examined for acceptability.
Additional examinations, such as PT, were performed if-the visual examination disclosed any questionable indication.
l The inspectors observed the arc-welding being-performed at the SIT erection site and noted that spare welding rods were kept in'a heated chamber approximately 100 feet from the tank erection site and held at a
temperature of 170 F.
Some rods were transferred to an insulated heated
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canister at the erection site to keep the welding rods warm, dry and
unexposed to the ambient environment before actual use at the erection j
site. This procedure provides adequate control to ensure good weldability l
of the tank shell plates.
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The inspectors noted welding arc strikes on the cylindrical side
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plates of the SIT.
The licensee stated-that these strike marks would be
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removed by grinding and the plates visually inspected for = acceptability.
If the ground surface indicates a possible crack, further examination-such as PT will be performed in accordance with the YAEC Construction Specifica-tions to determine the extent and nature of the crack. The Construction Specification provides for welding procedures, qualifications and heat input control to prevent sensitization of-the stainless steel.
5.0 Plant Walk-Down of Safety injection System Pump and Piping Areas.
The inspectors performed a general walk-down of the SI pump room and lower safety injection piping system room.-
r-ing the walk-down it was noted that boric acid residue (white " flowers had been accumulating on the shaft seals of the three low pressure-satety injection pumps (LPSI),
In some cases, the' residue buildup was thrown on the floor after hitting i
the operating shaft.
Each' pump had a surrounding yellow / magenta line
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stripe on the floor warning of the possibility of contamination within the marked areas.
Survey instruments had been brought in to check whether the pieces of boric acid residue thrown to the floor showed signs of being contaminated.
The survey indicated.that no contamination ~was present on the floor.
Further inspection of the SI pumps-indicated that -
the No. 2 pump had considerable boric acid residue buildup at its
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horizontal cylinder joint, The inspectors expressed concern over any i
possible leak causing a longer term safety problem'or deleterious effect g
on the operation of the pump or by the boric acid residue being scattered
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beyond the delineated areas of the pump.
In another area, the inspectors observed that a similar boric acid residue had formed on a valve casing (CHV_772).
This was also called to
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the cause of this boric acid accumulation and its effect on the safety _
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function of the system.
The existence of boric acid residue as evidence of leakage cannot be avoided in the. safety injection pump shaf t seals, but -
buildup of the residue can be controlled.
6.0 General Engineering Procedures
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A discussion was held with licensee engineers to determine whether the
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engineering organization participates in assuring that' safety matters are
resolved in a manner consistent with good engineering practice. The licensee gave several examples of engineering activity as well_as
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providing documentation of engineering procedures cor.sistent with good engineering practice.
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The EDCR document is illustrative of the performance of both headquarters
.and plant site engineering in providing for an engineering and economic evaluation based decision to replace the SIT which had shown evidence of long' term deterioration. Discussed inLthe document were the design, procurement procedures and the fabrication of the replacement SIT. The t
many engineering sonsiderations included a complete engineering
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evaluation of the safety implications of SIT-replacement.
Engineering responsibilities for SIT replacement were clearly defined in a-project organization utilizing engin.eering personnel with direct responsibility
for the replacement activities.
Specialized expertise had beer.
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appropriately retai.ied from both the Headquarters Division in Bolton and from outside consultants.
YAFC supports the engineering development activity of EPRI and provides an environment for engineering participation in engineering society activities. -These types of activities provide for an interchange of, technology with other utility engineering organizations within and
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outside YAEC.
Other engineering activities include application of the concepts of group interaction meetings, probabilistic risk-assessment, root cause evaluation, lessons learned, and self assessment.
From the discussions held with the engineering personnel, there appear.to be no engineering procedural or organizational impediment to plant safety.
7.0 General Operation Records The inspectors requested from the licensee a description of the operating transients to which the plant had been subjected throughout.its operating lifetime.
This request was made to determine the extent of the-licensee identified and recorded thermal cycling transients.
The, licensee presented to the inspectors a listing of the date and duration of all fatigue cycles
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I from 11/14/60 through 8/25/89.
(This listing appears in OP-7094.1). This
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list identifies the start up and shut down transients of the plant for i
comparison with the number of transients for which the plant compor,ents
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have been designed.
The inspector found that the listing of fatigue
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cycles for the plant was complete and ensured that adequate documentation-exists for reviewing the remaining fatigue life of individual components
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for plant life extension.
I 8.0 Pressurizer Cracking History It was called to the attention of the inspectors that a raview by the licensee had been made of existing indications in the pressurizer cladding.
Indications had been found during inspections in 1966, 1977, 1978, 1981 and 1984.
The indications were located at-the 15 foot shell.
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weld, the 19 foot water level and at the 2 foot top-head-to-shell weld.
The licensee informed the' inspectors that these regions would be reinspected j
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9.0 Follow-up on Previously Identified Items-(OPEN) Unresolved Item 50-029/90-04-01:
This item pertains to discrepancies found'concerning pipe support locations, "as-built" configuration, and in some cases missing pipe supports in safety-related piping systems in the plant.
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The inspector reviewed ~the-licensee's follow-up' actions in response to a missing support in-the spent-fuel pool (SFP) cooler and the support CRE-H-10. The above discrepancy and other discrepancies in the "as-built" configuration of other supports in some safety related system raises questions regarding the adequacy of the licensee's-original efforts in response to IEB 79-14.
In the original efforts (IEB 79-14) to assure the "as-built" adequacy of pipe supports, the licensee used two organizations:
CYGNA Energy
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Services (CYGNA)'and Yankee Atomic Energy Company (YAEC), to perform
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walk-down. inspections and to document, analyze and resolve any identified i
discrepancy.
The current pipe support discrepancies are in systems that-were inspected by YAEC.
The licensee initiated a reinspection of those systems inspected by YAEC to ascertain the adequacy of the' original (79-14) inspection.
The current inspection again identified several deficiencies.
These. findings were not yet evaluated for their impact.on systen' sa f ety.
The initial scope of-the current reinspection did not include systems'
inspected by CYGNA. 'However, in the light of the questions regarding-the adequacy of YAEC-original (1979-80)-inspection, the licensee committed to:
include some systems originally inspected by CYGNA.
This item remains open pending completion of the licensee's' reinspection efforts and evaluation of findings as to their-impact on system. safety, i
(CLOSED) Unresolved Item 50-029/90-03-01 Duric; the last inspection of the original safety injection tank (SIT)
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(TK-28), it was reported in Inspection Report (IR) No. 50-029/90-03 that
the licensee would provide for observation of leakage rate and.any extension of a 2.6 inch indication on the tank lower shell surface.
Should the observed indication extend by an amount greater than.25 inches, a retssessment would be made of tank operability.
Since that time, the leak rate increased from 1.5 GPD_to 2.2 GPD on June 17, 1990.
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However, the leakage at the present time'is holding steady at that level, The progression of the indication length remained below the limit.
The SIT cracking issue was considered an unresolved item in IR 50-029/90-03, pending receipt of further technical information justifying continued operation.
Because a decision had been made to replace the SIT, and the replacement is in progress, the issue no longer remains an unresolved item.
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.j i-10.0 Documents Reviewed
NRC Region I-Inspection Report 50-029/90-03
Yankee Project Procedure No. 17, Design Change Plan & Control
. System, Rev. 8, 2/23/90.
Memorandum, YRP 668/90, Erosion-Corrosion Monitoring Program at
YNPS, 5/31/90.
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YRP 400/90, Organization for MOV Program to Support 1990 Refueling,.
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4/10/90,
YRP 410/90, Project Engineering Personnel-to. Assist During 1990
Refueling, 4/4/90.
Procedure OP-7004, Rev. 5, Yankee-Reactor Vessel Fatigue Cycle Log,
5/89.
E0CR 90-301, Safety Injection Tank. Replacement, Change No; 1,.5/22/90.
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11.0 Unresolved Items Unresolved items are matters about which tore'information is required in order to ascertain whether they are acceptable, violations, or deviations..
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Unresolved items are discussed in Section 9.0.
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12.0 Management Meetings The licensee's management was informed of the. scope and purpose of the
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inspection at the entrance interview on June 19, 1990.. The findings of the inspection were discussed with the licensee's representatives during i
the course of the inspection and presented.to the licensee's management =
l at the exit interview on June 22, 1990 (See Section 1.0_for~those who attended).
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No written material was provided to the licensee by the inspectors. :The licensee did not indicate that proprietary information was involved within the-scope of this inspection,
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