IR 05000317/1975017
| ML19329C801 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs, Davis Besse  |
| Issue date: | 08/06/1975 |
| From: | Knapp P, Meyer R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19329C786 | List: |
| References | |
| 50-317-75-17, NUDOCS 8002190911 | |
| Download: ML19329C801 (9) | |
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I:I Forrt '12
Jan 75) (Rev)
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TD U. S. NUCLEAR REGULATORY CO.T11SSION d'
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OFFICE OF INSPECTION AND E.TORCDIE q
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REGION I
I Inspection Report No:
50-317/75-17 Docket No:
50-317
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icensee:
Baltimore Gas and Electric Comnany License No:
DPR-53 Cas and Electric Buildine Priority:
Charles Center Category:
C Baltimore, Maryland 21203
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Safeguards Group:
aca tion:
Calvert Cliffs 1. Lusbv, Marvland ype of Licensec:
PW, 2 560. %'t (CE)
ype of Inspcetion:
Special' Inspection ates of Inspection:
July 1-2, 1975 ates of Previous Inspection:
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eporting Inspector:
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O 5 7U R.J.heyer,FddiationSpecialist DAIE ccccpanying Inspectors:
None
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DATE DATE
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DATE ther A$.. - -cc=panying Pers'ennel:
None
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DATE
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cviewed By : \\.\\ * (~~ N b - A c._.2 O.
%-G-/7 P. J. Knapp, Chief, Facilift'es Radiological DATE Protection Section Enclosure 3 Attachment 2 O
8002190///
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SUIStARY OF FINDINGS Enforcement Action A.
Items of Noncompliance 1.
Violations None 2.
Infractions None 3.
Deficiencies
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None B.
Deviations None Licensee Action on Previousiv Identified Enforcement Action Not applicable Other Sionificant Findings A.
Current Findines 1.
General The inspection was specific to a review of circumstances re-lating to an unplanned release of radioactive gas to the Auxiliary Building, with subsequent release via the plant vent.
Inspection findings shewed that the release resulted from ex-cessive leakage of degassing primary coolant through the piston rod packings on charging pumps Nos. 11 and 13.
The licensee initiated investigative actions upon receipt of radiation monitor alarms and other indicators and took corrective actions to terminate the release upon identification of the leak.
Max-imum personnel contamination, resulting from the gas permeating the hair and clothing, was 4,000 disintegrations per minute (dpa)
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l per probe area. No personnel overexposures occurred.
Release rate from the plant vent was approximately 47. of the technical specification licit.
Licensee reported the event in accordance l
with technical specification requirements.
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2.
Unresolved Item
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I Licensee's program to review and resolve air balance problems in the Auxiliary Building.
(Details, Paragraphs 52 & E)
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3.
Infractions and Deficiencies Identified by Licensee
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Not applicable i
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Status of Previously Reported Unresolved Items
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l Resolution of waste gas system problem remains unresolved.
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l (Ref: IE Inspection Reports 50-317/75-10 and 50-317/75-15)
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Management In t e rview The following individuals attended the management interview at the con-clusion of the inspection on July 2, 1975, s
R. Douglass, Chief Engineer J. Tiernan, Radiation Safety and Chemistry Engineer The following subjects were discussed:
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A.
The inspector stated that the inspection was limited to a review of the circumstances relating to the unplanned gaseous release
occurring on July 1, 1975 and that no ite=s of noncompliance had
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b3en noted in the areas of review.
(Details, Paragraphs 2-5)
B.
The inspector discussed the air balance problems he had noted during the inspection.
The licensee stated that the air balance would be evaluated and corrective measures accecplished.
Tentative completion
j schedule was established as one month, that is, about August 1, 1975.
The inspector identified this as an unresolved item pending completion of program.
(D'etails, Paragraphs 5.a & b)
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DETAILS
A 1.
Persons Contacted R. Douglass, Chief Engineer
J. Tiernan, Radiation Safety and Chemistry Engineer A. Kaupa, Staff Engineer, Chemistry J. Speciale, Rad-Chem Foreman J. Schlag, Principal, Rad-Chem Technician P. Steinbach, Resident Engineer, BG&E, Unit 2 J.11111, Shif t Supervisor, Operations 2.
Event Chronolocy Sequential aspects of the event, as determined from the Health Physics Log and survay records, Control Room and Shif t Supervisor's Log and discussions with licensee representatives, were as follows:
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0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />
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Two individuals exiting frca the Auxiliary Building, Unit 1 side, with personal clothing
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contamination. (4,000 dpm).
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Received a control room alarm on the fuel handling area ventilation radiation =onitor.
i 0915 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.481575e-4 months <br />
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Auxiliary Building evacuated; other radiation monitor readouts reviewed.
Twelve individuals exi~ing from the auxiliary i
building, Unit 1, with.ntamination on their
j person and clothing (1,500 to 4,000 dpm).
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0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> Initiated investigation which included general and
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specific air sampling and contamination surveys in the Auxiliary Building.
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Continued the above to 1540; termination of event.
0945 hours0.0109 days <br />0.263 hours <br />0.00156 weeks <br />3.595725e-4 months <br />
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Sampled plant vent exhaust.
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1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />
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Evacuated construction workers, Unit 2 side -
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Precautionary action - All individuals received I
personal survey - No personal contamination l
experienced.
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1018 hours0.0118 days <br />0.283 hours <br />0.00168 weeks <br />3.87349e-4 months <br />
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Leak source identified as charging pumps: No. 11
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charging pump stopped - leak at piston rod packing.
j 1025 hours0.0119 days <br />0.285 hours <br />0.00169 weeks <br />3.900125e-4 months <br />
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No. 13 charging pump stopped and isolated for maintenance - leak at piston rod packing.
1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br />
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Plant vent monitor trend turned down.
1205 hours0.0139 days <br />0.335 hours <br />0.00199 weeks <br />4.585025e-4 months <br />
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Started fuel handling area ventilation system.
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No. 11 charging pump isolated.
1210 hours0.014 days <br />0.336 hours <br />0.002 weeks <br />4.60405e-4 months <br />
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1415 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.384075e-4 months <br />
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Plant vent monitor returned to normal.
1445 hours0.0167 days <br />0.401 hours <br />0.00239 weeks <br />5.498225e-4 months <br />
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Unit 2 released to nor=al status.
1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br />
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Sampled plant vent, normd1 background.
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1555 hours0.018 days <br />0.432 hours <br />0.00257 weeks <br />5.916775e-4 months <br />
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Stopped fuel handling area ventilatien system.
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l 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />
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Charging pumps returned to service.
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Release Startsti c j
Relecse Rate Release Rate Limit (T/S)
Total Release
53 1.8X10 m /sec.
3.85X10 m /sec. 100 C1 (Xenon-133 &
135)
<0.002 uCi/sec.
2.0 uCi/sec.
30 uCi (Iodine-131: '
Particulates (>8 day Tg)
Not detected l
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Summary Description i
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a.
On July 1, 1975 at approximately 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br />, two individuals, exiting from the controlled access area had detectable con-tamination (4,000 dpm) on their person and clothing.
At approx-imately the same tira the fuel handling area gaseous monitor
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alarmed. Various other monitoring systems were showing higher
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than normal radiation levels.
Personnel contamination events
and radiation monitors indicated that airborne radioactivity i
was present in the Auxiliary Building.
Evacuation of the building was initiated. At 0915 hours0.0106 days <br />0.254 hours <br />0.00151 weeks <br />3.481575e-4 months <br /> fourteen individuals exited from the area.
These individuals were also contaminated to comparable i
levels.
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b.
An investigation to determine the cause was initiated.
This included general and specific air samples and surveys of the Unit 1 and Unit 2 sides of the Auxiliary Building.
Airborne radioactivity above the normally experienced activities were found to be generally present on the Unit 1 side.
At approx-imately 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />, the Unit 2 side, occupied by construction workers, was evacuated through established check points.
No personal contamination was detected on these individuals.
These individuals were evacuated as a precautionary measure, in that the Auxiliary Building is common to both units and separated only by a security fence with Unit 2 being maintained as an unre-stricted area.
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Through continuing surveys, the source of the gaseous leakage >
was determined to be the charging pumps.
Specifically, pumps No. 11 and 13 were leaking primary coolant through the packing on the piston rods. Degassing of the primary coolant occurred in the charging pump rs'm and the Auxiliary Building sump, located outside the room and immediately adjacent to the separating fence between Unit 1 and Unit 2.
This is an open sump and collects water from the floor drain in the charging pump room.
This sump is at the minus 10 foot level immediately adjacent to the separating fence between Units 1 and 2.
Some gaseous activity exfiltrated to the Unit 2 side but was limited tc a small area.
The area was not occupied and air concentrations did not exceed applicable limits, d.
Upon determination that the charging pumps were the source of leakage, pump No. 11 was shut down at 1018 hours0.0118 days <br />0.283 hours <br />0.00168 weeks <br />3.87349e-4 months <br /> followed by shutdown and isolation of pump No. 13 at 1025 hours0.0119 days <br />0.285 hours <br />0.00169 weeks <br />3.900125e-4 months <br />.
The pump packings were subsequently replaced and the pumps were returned to service at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br />.
Subsequent to the determination that off-gassing was occurring at the auxiliary sump, the sump was equipped with an exhauster that exhausts back to the charging pump room.
This eliminated distribution of gaseous activity to the building prrper.
By lj]0 hours air concentrations were returning to normal e.
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uCi/ml). The Unit 2 side yas returned to unrestricted access status at '.445 hours0.00515 days <br />0.124 hours <br />7.357804e-4 weeks <br />1.693225e-4 months <br />.
During the course of event no individuals were exposed to excessive air concentrations of radioactivity.
Isotopic analysis showed the predominant isotepe
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to bc Xenon-133.
Othcr identified isotopes included Xenon-135 and the particulates, Cesium-138 and Rubidum-88.
Iodine and
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long lived particulates were not identified in general grab
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samples; however, Iodine-131 was collected on the charcoal filter in the main vent sampling system.
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The licensee issued a press release on July 1, following the event. On July 2, the day following tha event, licensee
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representatives participated in a construction employee safety meeting to describe the event and answer employee questions.
The inspector attended this meeting as an observer.
Specific concerns were not raised by attending employees.
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5.
Inspection Findings a.
During the course of the inspector's review of the event, survey results suggested that air balance in the Auxiliary Building was less than desirable.
It was noted that elevated air concen-trations existed in areas far removed from the source of leakage, specifically the fuel handling area which is several elevations removed.
The inspector conducted smoke tests to determine existing air flow direction. The tests were conducted on July 2, 1975.
Test results are noted below:
-15' Elevation - At the fence separating Units 1 and 2 flow was from Unit 1 to Unit 2.
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-10' Elevatien (Source of leakage elevation) - Flow was from the j
corridor to the charging pump room. At the separating fence near the Auxiliary Building sump area, flow was stagnant with slow
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drift from Unit 1 to Unit 2.
At the elevator vestibule near the i
Auxiliary Building sump, flow was generally to and into the i
elevator.
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Elecation - Flow was from the elevator to the vestibule.
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the degassifier room flow was from the corridor to the room. At the VCT room flow was to the room.
At the separating fence near i
the VCT room flow was from Unit 1 to Unit 2.
Near the boric acid storage tanks at the separating fence, flow was from Unit 1 to Unit 2.
Near the waste gas room at the separating fence flow was from Unit 2 to Unit 1.
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+27' Elevation - Flow was from the elevator to the vestibule to the corridor.
Flow at the heat exchanger room was =arginally from the corridor to the room.
At the separating fence flow was from Unit 2 to Unit 1.
Along the valveway flow was from the rooms to the corridor.
At the letdown filter room entrance, flow was stagnant.
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+45' Elevation - Flow v>s from the elevator to the vestibule and the general area.
At the separating fence in the cask loading area flow was from Unit 1 to Unit 2.
+69' Elevation - Flow was from the elevator to the vestibule to the fuel handling area to the passageway connecting the access control point.
b.
The inspector reviewed the results of the smoke tests with the licensee. The licenree agreed that air balance problems existed in the Auxiliary Building and stated that a program to evaluato
and correct these problems would be initiated.
The licensee established a tentative completion date for this program as one month from the date of the inspection.
The inspector stated this would be considered as an unresolved item and reviewed during subsequent inspections.
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A L LdC1124t&& L J Evaluation and Clarification of Incident
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Personnel were exposed to low levels of airborne radioactive T.aterials (less than 2% of the Maximum Permissible Concentration).
The concentrations of airborne radioactive material im Units 1 and 2 were measured and the times that persons were present in these con-centrations were determined. Based on this infor=atien it was deter-mined that personnel in Unita 1 and 2 were exposed to approxinately 0.9% and 1.7% of the applicable limits, respectively.
The reactor coolant pumps were not involved in this incident in any way. The leaking packing was on the pistons of the positive displace-cent coolant charging pumps. This packing has a design leakage at all times and the auxiliary building is designed to contain radio-active materials released from this leakage.
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Enclosure 3 fetachment 3 omes *
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