IR 05000312/1979001
| ML19282B084 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 02/01/1979 |
| From: | Faulkenberry B, Andrea Johnson, Miller L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML19282B082 | List: |
| References | |
| 50-312-79-01, 50-312-79-1, NUDOCS 7903090002 | |
| Download: ML19282B084 (6) | |
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U. S. NUCLEAR REGULATORY COMMISS10l1 0FFICE OF IllSPECTIO?! AliD EI'FORCEMEi1T REGI0fl V Report flo. 50-312/79-01 Docket flo. 50-312 License flo. DPR-54 Safeguards Group Licensee: Sacramento flunicipal Utility District P. O. Box 15830 Sacranento, California 95813 Facility flame: Rancho Saco Inspection at: Clay Station, California Inspection Conduc ed: January 5, 6, 8, and 18,1979
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[, /h 79 Inspectors:
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D,. Johnson, actorInspectog Date' Signed
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I 'l 7 '1 L'. F. til.ler,. Reactor, I spector Date Signed'
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P. 'O. Mor7_11, Reactoy Inspector Date Signed i
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Personnel: J.1. CNtis' Chief, Reactor Operations and Date Signed
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fluclear Support Branch bDh ci n k l. [b -
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B. H. Faulkenberry, Chjefr Rec, tor Projects Date Signed a
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Section #2 ID N k nn50(,h._
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,,979 Approved by:
B. H. Faulkenberry, Chief,Jeactot Projerts Da'te Signed Section #2, Reactor Ope (ations'a'nd Muclear Support Branch
Inspection on January 5, 6, 8, and 18,1979 (Recort t!o. 50-312/79-01)
Areas Inspected:
Reactive, unannounced inspection of reportable occurrences involving (T)later hammer on December 15, 1978, in the decay heat system (DPS), and (2) loss of integrated control system (ICS) neuer on January 5,1979, causino a unit trin ard e cooldmn rate th' w eeded technical snecification (TS) lirnits.
This insnection involved 50 hurs onsite by three inspectors.
Results:
!!o items of noncompliance or deviations were identified.
790309000>
IE:V Form 219 (2)
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DETAILS 1.
Persons Contacted
- J. Mattimoe, Assistant General Manager
- R. Rodriquez, Manager, Nuclear Operations
- P. Oubre, Plant Superintendent
- R. Colombo, Technical Assistant
- W. Ford, Operations Supervisor J. McColligan, Technical Supervisor
- G. Coward, Maintenance Supervisor
- D. Blackly, Mechanical Engineer
- W. Garrett, Plant Mechanical Engineer
- J. Parman, Quality Control Inspector
- J. Field, Plant Mechanical Engineer
- F. Bamford, quality Assurance Coordinator The inspectors also talked with and interviewed several other licensee empicyees, including members of the engineering, main-tenance, operations, and quality assurance (0A) organizations.
- Denotes licensee personnel attending management meeting on January 8, 1979.
2.
Reoortable Occurrence Follow-up a.
Water Hammer Event on December 15,1978 (LER 78-17)
On January 3,1979, the Sacramento Municipal Utility District (SMUD) submitted a letter report to the IE Region V office regarding a " water hammer" event in the decay heat system (DHS) caused by starting the "B" DHS pump with the suction valve from the borated water storage tank closed. The li-censee letter stated that an examination of the DHS had revealed that two rigid pipe supports had been pulled from the wall and were loose (Nos. 4S-26101-8 and 4U-25021-9).
Pursuant to an agreement made on Decenber 15, 1978, at an NRC exit interview (Inspection Report No. 50-312/78-20 and con-firmed by an NRC immediate action letter dated December 20, 1978), the licensee had also examined four hydraulic shock suppressors and determined that one snubber (No. 32, 4SW-26101-6)
poppet valve and seat had been damaged. The licensee's letter stated that the items described above had been repaired and that operating personnel would be cautioned by a memo regarding the water harner proble.
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-2-e Two flRC inspectors arrived at the plant site on January 5,1979, to examine the circumstances surrounding the water hammer event and to verify the licensee's corrective actions. The inspectors interviewed management, engineering and operations personnel and examined the following records.
(1) flonconformance Report (t CR) i;o. S-ll26, dated December 18, 1978, describing the damaged pipe supports discovered on the "B" DHS after the December 15, 1978, water hammer.
(2) flonconformance Report t!o. S-909, dated August 23, 1978, describing three DHS supports found to be degraded by spalling and splitting around support anchors.
One sup-port (40-25021-9) was also included in f;CR S-ll26.
(3) Plant Review Committee (PRC) Meeting Minutes No. 574, dated December 21, 1978, which documented the licensee's determination that the water hammer event was reportable due to snubber and support damage.
(4) Work Request No. 032887, dated 12/18/78, which was written
_ to remove and test snubbers !!o. 30, 32, 34, and 35.
(5) Piping isometric drawings 26101-18"-GD, 20024-12"-GD, 20026-12".r,D, and 25021-16"-HD, Sht. 4.
(6) Shift Supervisor and Control Room Legs for December 15-19, 1978.
The inspectors examined selected portions of the "A" and "B" DHS piping as well as the repaired components to verify the adequacy of the repairs.
The following were inspector observa-tions and statements made by licensee representatives:
(1) Three additional DHS pipe supports showed evidence of damage (looseanchor bolts and concrete spalling), one in the "A" pump room and two in the "B" heat exchanger room. Licensee representatives stated that a thorough examination of the DHS piping and. supports would be per-formed, all damaged supports identified would be repaired, and all snubbers located between rigid supports where there was evidence of support danage for the associated piping would be tested before starting up the plant.
(The plant had tripped at approximately 12 A'1 due to a loss of Integrated Control System power).
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The licensee representatives also stated that f1RC Region V personnel would be informed of completion of this work prior to taking the reactor critical to allow an fiRC inspector to return to the site and examine the repairs.
(2) The licensee representative stated that information concerning the water hammer event was reported to f!RC by letter dated January 3,1979, and that a special re-port would be sent to flRC-DOR as requested in a letter to the licensee dated September 2,1977. The inspectors directed the licensee's attention to the pertinent sec-tions of the tecnnical specifications that require submittal of a licensee event report (LER). The licensee representative stated that a report would be submitted as prescribed by the technical specifications.
(3) Licensee representatives stated they had experienced events of similar nature (vibration) in the past from the opening of the DHS suction valve.
Reportedly, the operations supervisor discussed the event of December 15, 1978, with all operating shift personnel and was planning
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to issue a Special Order on the subject.
(4) The work request (fio. 032887) that controlled inspection, repair, and testing of the affected snubbers indicated that the snubbers were reinstalled and inspections com-pleted on December 19, 1978.
However, the document showed that the equipment was returned to service on December 22, 1978.
The reactor was returned to power operation on December 19, 1978.
Examination of the pertinent admin-istrative procedure, AP-3, requires that when work is completed the shift supervisor will sign the work requests and forward them to the plant scheduler. The licensee representatives assured the inspectors that the snubbers had been satisfactorily returned to service before the reactor was returned to operation and that the work re-quest procedure would be examined and changed, if necessary, to assure that all personnel understand the administrative procedural requirements.
Prior to returning the plant to power operation, a licensee representative contacted IE Region V personnel to infom them that the pipe support repairs mentioned above had been com-pleted and the plant was ready to start up.
Reportedly, no additional damaged supports were identified and no additicnal snu54 m 'zerc # # e i? n
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An inspector returned to the site on January 6,1979, after plant startup, to examine the pipe support repairs.
The inspector conducted an examination of the "A" and
"B" DHS suction piping and interviewed licensee engineers ing and maintenance personnel. The inspector verified that the damaged pipe supports had been repaired and that there were no additional damaged supports.
The inspector observed that snubbers numbered 33, 36, and 37 were associated with the damaged pipe support in the "A" pump room, were located inside the boundary of rigid undamaged supports, and had not been tested by the licensee.
Licensee per-sonnel stated that these snubbers would be tested within two days and the results would be reported to the NRC Region V office by telephone.
Subsequently, IE Region V personnel arranged for a management meeting on January 8, 1979, to discuss the water hammer event and associated repairs.
b.
Loss of Integrated Control Systen (ICS) power on January 5,1979, causina a unit trip and a cooldown rate that exceeded technical ~
specification limits.
LEiF7F01)
On January 5,1979, at approximately 12 o' clock noon, the reactor tripped due to an accidental loss of ICS power. The inspector interviewed licensee operations and engineering per-sonnel and examined appropriate logs and records of the trip to verify that regulatory requirements had been met and that appropriate corrective actions were completed by the licensee.
The inspector obsegved that the reactor coolant temperature dec5easedfrm580 F (when the trip occurred) to approximately 435 F within ten minutes.
One hour later the temperature was 51 5 F.
The inspector verified that the licensee had received ccncurrgnce from the USSS vendor that cgntinued operation after the 120 cooldown (computed as 550-430) was justified, and that the technical specification pressure-temperature limits for operation were not exceeded. The corrective actions planned by the licensee were also examined and found to be consistent with that described in LER 79-01.
No items of noncompliance or deviations were identified.
3.
ECCS Procedure The inspector examined Licensee Procedure D.5, " Loss of Reactor Coolant / Reactor Coolant Pressure," and discussed this procedure with coerations personnel.
The inspector narticinated in a drill
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which verified that the high pressure injection cross connect valve (s) could be opened within ten minutes; specifically, a simu-lated small break in the primary coolant system was initiated in the reactor control room. The inspector accompanied an operator from the control room to the subject valve.
This action took 213 minutes.
The operator simulated the opening of the valve which was estimated to take another 2 minutes. The total time required to walk from the control room and cpen the valve was determined to be approximately 4S minutes.
No items of noncompliance or deviations were identified.
4.
Exit Interviews On January 8,1979, the inspectors and Region V management personnel met with licensee personnel denoted in Paragraph 1 to discuss ccm-nunications with the regional office, Technical Specification re-porting requirements and follow-up of licensee corrective actions.
The licensee representatives made the following statements.
a.
The letter report on the water hammer event on December 15, 1979, would be resubmitted as a LER.
b.
The DHS including the associated supports had been thoroughly examined and no additional damage was discovered. The three snubbers identified as requiring a bench test had all been satisfactorily tested and returned to service.
c.
An engineering evaluation of the DHS would be performed by a consultant to assure that the system design and construction is adequate to perform its safety function as described in the Rancho Seco safety analysis report.
On January 18, 1979, the licensee informed the inspectors that an engineering representative of Bechtel Corporation was per-forming the evaluation and that he had been onsite and examined the system.
On January 18, 1979, the licensee representative also indicated that administrative controls and procedures will be evaluated to assure that future services performed onsite by vendors and contractors will be adequately monitored, and that documentation involving the return of plant equipment to service will clearly show control by operations personnel.