ML20133C562
| ML20133C562 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 09/30/1985 |
| From: | Hueter L, Schumacher M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20133C517 | List: |
| References | |
| 50-454-85-38, 50-455-85-42, NUDOCS 8510070427 | |
| Download: ML20133C562 (7) | |
See also: IR 05000454/1985038
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U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports No. 50-454/85038(DRSS);.50-455/85042(DRSS)
Docket Nos. 50-454; 50-455
Licenses No. NPF-37; CPPR-131
Licensee:
Commonwealth Edison Company
Post Office Box 767
Chicago, Illinois 60690
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Facility Name:
Byron Nuclear Station
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Inspection At:
Byron Nuclear Station, Units 1 and 2
Inspection Conducted: August 28-29, 1985
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Inspector:
L. J. Hueter
7-30 -75-
Date
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Approved By:
M. C. Schumacher, Chief-
Independent Measurements and
Date
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Environmental Protection Section
Inspection Summary
Inspection on August 28-29, 1985 (Reports No. 50-454/85038(DRSS);
50-455/85042(DRSS))
-Areas Inspected:
Nonroutine, announced inspection of an occurrence involving
initiation of a liquid radwaste release without required dilution prior to
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release to an unrestricted area.
Also inspected was the gaseous and liquid
radwaste startup program for Unit l'
'The inspection involved 15 inspector-
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hours onsite by one NRC inspector.
Results: Two violations were identified (failure to follow liquid radwaste
release procedures - Section 2 and failure to take timely action when a
Technical Specification LC0 release limit was exceeded - Section 2).
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DETAILS
1.
Persons Contacted
1A. Chernick, Compliance Supervisor
1J. Langan, Compliance
1R. Pleniewicz, Assistant Superintendent, Operation
R. Querio, Byron Station Superintendent
A. Scott, Health Physicist
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1J. VanLaere, Rad-Chem Supervisor
1234K. Weaver, Station Health Physicist
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1F. Willich, QA Inspector
P. Brochman, NRC Resident Inspector
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1J. Hinds, Jr. , NRC Senior Resident Inspector
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1 Attended the August 29, 1985 exit meeting.
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2 Telephone conversation September 3, 1985.
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3 Telephone conversation September 5, 1985.
4 Telephone conversation September 20, 1985.
2.
Liquid Radwaste Release Incident - August 22-23, 1985
On the afternoon of August 22, 1985, steps were taken to initiate a batch
release, Release No. 50489, from a liquid radwaste tank.
The prerequisites,
including sampling, chemical and radioactivity analyses, radwaste and
dilution flow rates, monitor alarm / isolation setpoint determinations, and
associated paperwork with verification / approvals required by procedures
were initiated.
The principal procedure for liquid releases is BCP 400-T50,
Revision 3, " Liquid Radwaste Release Form", which has a number of temporary
changes in effect.
The release was initially started at 19:22 on August 22 with a release
rate of 315 gpm and circulating water blowdown rate (dilution) of
24,000 gp"i.
However, the release was stopped 40 minutes later at 20:02
(tank level at 58%) at the request of the Station Control Room Engineer
(SCRE) due to the need to stop circulating water blowdown flow because of
the lowering water level in the circulating water flume.
Following the
termination of the release, the circulating blowdown flow was terminated
to allow the circulating water level in the flume to rise to the desired
level.
After reaching the desired level it was planned to restart the
circulating water blowdown flow but at a lower release rate (15,000 gpm)
and then restart the liquid radwaste batch release.
A new procedure
package was initiated for this renewal of Release No. 50489.
Portions of the procedure which required no change were signed off with
the notation " performed previously."
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In Section F, " Operating Department Responsibility - Discharging Release
Tank to Circulating Water Blowdown Line," of procedure BCP 400-T50,
Step 1.c. has provisions for date and initials of both the radwaste
operator and radwaste foreman for verification that the circulating water
blowdown rate is equal to or greater than the minimum rate stated in
Section C, Step 3 (determined by health physics personnel) which was
15,000 gpm for the renewal of Release No. 50489.
At 23:28, at the request of the radwaste foreman, the radwaste operator
made a telephone call to the center desk operator (nuclear station
operator (NS0)) in the reactor control room to verify the circulating
water blowdown rate was at least 15,000 gpm.
The NS0's initial response
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was " Blowdown? We don't have any blowdown going." However, while still
on the line he asked another occupant of the control room a question
which the radwaste operator could not hear well. When the NSO came back
on the line, the radwaste operator understood him to say that the blowdown
rate is 15,000 gpm on the low end after which the radwaste operator asked
"15,000 gpm?" and the NSO states "Yes."
(However, the NSO in a written
statement, said he told the radwaste operator that 15,000 gpm was the
flow rate that would be established when blowdown was started).
The
radwaste operator proceeded to log the erroneous verification (due to
miscommunication of established circulating water blowdown rate) in
release procedure BCP 400-T50 in preparation for restarting the release
of Release No. 50489.
Following the telecon between the radwaste operator
and the NSO, the radwaste foreman asked the radwaste operator for the'
rate of circulating water blowdown and he was told 15,000 gpm on the low
end. The radwaste foreman also proceeded to log the erroneous verifica-
tion of established circulating water blowdown rate in release procedure
BCP 400-T50.
Following completion of several more steps on the release
procedure, the release tank outlet valve / isolation valve was unlocked and
opened following which the discharge flow control value was slowly opened
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at 23:59 on August 22, to the release rate of 300 gpm (within the 350 gpm
allowed in Step 3 of Section C of the release procedure).
This action
initiated a liquid radwaste release into the circulating water blowdown
line (which drains to the Rock River) without operation of the circulating
water blowdown flow to provide required dilution before release to an
unrestricted area.
Procedure OBCS 11.1.1.1-1, Revision 1, which requires
the release tank to be released with the circulating water blowdown system
flow rate as specified in the Liquid Radwaste Release Tank Form
BCP 400-T50, was not followed.
Failure to positively verify that
circulating water blowdown flow rate existed before initiating the
liquid radwaste release and failure to have the circulating water
blowdown flow rate specified in Release Procedure BCP 400-T50 while
making a release from the radwaste release tank were identified by the
inspector as a violation of Technical Specification 6.8.1.a which
requires implementation of procedures for effluent discharges
(Violation 454/85038-01).
The circulating water blowdown line monitor alarmed in the reactor control
and was observed / acknowledged by the NSO within the first minute after the
release from the radwaste tank was initiated.
The NSO discussed the alarm
condition with the SCRE.
Unaware that a radwaste release had been
initiated, they initially believed it might be a spurious alarm.
The NSO
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then made a phone call to notify the shift engineer (SE).
The SE asked the
NSO to call the radwaste operator to ask if any radwaste release was in
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progress.
The NS0 then called the radwaste operator and was informed that
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a radwaste release was in progress.
The NSO informed the operator that
circulating water blowdown flow had not been established and instructed the
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radwaste operator to terminate the release which he did at 00:09 on
August 23, ten minutes after the release had been initiated.
During the
ten minutes, about 2700 gallons of liquid radwaste containing a
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radionuclide mixture with a concentration of about 30 times the limit
specified in 10 CFR Part 20, Appendix B, Table II, Column 2, was released
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from the radwaste release tank into the circulating water blowdown line
which drains to the Rock River.
During this release, the circulating water
blowdown flow rate (intended at 15,000 gpm) had not been established to
provide necessary dilution
Action a. of Technical Specification
3.11.1.1 requires that when the concentration of radioactive material
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released in liquid effluents to unrestricted areas exceeds the
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concentrations specified in 10 CFR Part 20, Appendix B, Table II, Column 2,
the concentration shall be immediately restored to within the above limits.
The nine minute delay between the actuation of the blowdown monitor alarm
and termination of the release appears inordinate and does not meet the
immediacy requirement of the technical specification.
This was identified
by the inspector as a violation of Technical Specification 3.11.1.1 which
requires immediate restoration to within the limits for release to an
unrestricted area (Violation 454/85038-02).
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The circulating water blowdown line is basically a 30 inch diameter pipe
about 13,000 feet long, common to both units.
It connects to the
circulating water system a short distance downstream of the condenser
water box of each unit and travels over several small hills and valleys
before splitting into two pipes that discharge into a small canal about
300 yards long that flows into the Rock River.
The blowdown flow is
normally controlled by a valve near the beginning of the blowdown line of
each unit before the blowdown lines combine into a common line. The
motive force is supplied by the circulating water pumps on the the
Valves are also located on each of the two
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pipes at the end of the blowdown line.
The ten minute release into the circulating water blowdown line was
terminated at 00:09 on August 23.
This situation was discussed between
operations personnel and onsite radiation protection personnel and it was
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decided to open the upper blowdown valve and close the lower blowdown
valves in an attempt to fill up the blowdown line for the benefit of
whatever mixing and dilution could be obtained before release into the
canal and Rock River.
At 00:15, six minutes after termination of the release, the upper
blowdown valve was opened.
At 00:23 and 00:29, the first and second
valves respectively on the lower end of the blowdown line were closed.
The latter two valves are located about five miles from the plant by
road.
Calculations indicate that closure at the end of the blowdown line
should have occurred several minutes before the bolus containing the
activity could have been released.
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A dip sample was collected at 00:50 from the canal at the discharge from
the blowdown line and subsequently analyzed.
At 00:56 both valves on the
lower end of the blowdown line were reopened to reestablish circulating
water blowdown release to the canal / river. Additional grab sample were
collected near the end of the blowdown via the composite sampler flow
path at 01:10, 01:30 and 01:50 and subsequently analyzed.
The concentration in the release tank was approximately 30 times the
unrestricted area release level based on observed concentrations of Co-58
(1.2E-3 pCi/ml), Co-60 (1.0E-4 pCi/ml), Mn-54 (1.0E-4 pCi/ml), and I-131
(3.6E-6 pCi/ml). The radionuclides identified in the grab samples and
their respective concentrations are as follows:
Time of Sample
Radionuclide
Concentration (pCi/ml)
00:56
Co-58
1.7E-7
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01:10
Co-58
2.8E-7
5.5E-8
01:30
Co-58
4.2E-7
01:50
Co-58
7.2E-8
Although these samples show dilute concentrations (unrestricted area
maximum permissible concentration (MPC) for Co-58 is 9E-5 pCi/ml), it is
noted that if the activity in the blowdown line were not well diluted the
bolus containing the bulk of the activity could have been released in a
period of a few seconds, between grab samples.
The licensee's evaluation concluded that the maximum instantaneous
concentration reaching the unrestricted area could not be determined but
was probably between 10 MPC and.the release tank concentration of 30 MPC.
On this basis the licensee plans to provide a 30 day written report
pursuant to 10 CFR 20.405(a)(1)(v) as noted in the licensee's Deviation
Report, 6-1-85-262, covering this event.
The licensee calculated the
dose to a member of the public from radioactive materials in this liquid
effluent release.
The dose was not significant in comparison with the
dose limits specified in Technical Specification 3.11.1.2.
The remainder of the water in the release tank was released without
incident beginning at 06:07 on August 23rd with proper circulating water
blowdown flow established to provide dilution.
A new procedure package
was not initiated for this third part of Release No. 50489.
The procedure
package used for the second part of the release was reused with new data
and new " sign offs" and the words "3rd Start" handwritten above or below
the data for the release procedure for the second part of the release.
This reuse of the release form together with handwritten temporary changes
gave a very cluttered appearance to the release procedure.
Although
apparently not contributing to this event, this clutter could increase
the potential for personnel error in following the release procedure.
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The licensee is conducting an investigation / evaluation of the event to
determine the cause, to take measures to prevent recurrence and to
improve the release procedures and control of releases.
As of the
inspection date it was concluded that the cause was a communications
problem and that the procedure for verification of circulating water
blowdown flow rate was a contributing factor.
A temporary procedure
change has been implemented to preclude recurrence which now requires
verification (initials and date) by a member of the reactor control room
(SCRE or RS0) as well as the radwaste foreman that the circulating water
flow rate is established at or above the minimum calculated rate needed
to provide adequate dilution before the control room SE or SR0 authorizes
the release.
This should preclude verification of dilution flow based
solely on telephone conversation.
A placard has also been prepared for
placing at the circulating water blowdown flow control valve while
releases are in progress.
The placard states " Release in Progress."
The placard's placement and removal are covered by procedure change.
To eliminate clutter and to enhance ease of following the radwaste release
procedure, it has been retyped to include all the temporary changes and
policy has been made to require use of a new procedure to continue release
from a tank once the release has been terminated.
Under consideration is
total review of the procedure for possible simplification and introduction
of a greater safety factor in the concentration planned for release to an
unrestricted area.
Also under consideration is a modification that would
have an isolation function on the radwaste release tank upon reduction or
loss of circulating water blowdown flow rate needed for dilution purposes.
Two violations were identified.
3.
Startup - Comcarison of Effluent Monitor Readings Against Known Effluent
Concentrations
The licensee has conducted tests involving laboratory analysis of gaseous
and liquid effluent samples and comparison of the results with respective
effluent monitor readings.
Good agreement was observed with the mcnitors
responding slightly on the high side (conservative).
No violations were identified.
4.
Startup - Demonstrate that Gaseous and Liquid Radioactive Waste Systems
Operate Per Design
The licensee has demonstrated that gaseous and liquid radioactive waste
processing, storage, and release systems operate in accordance with the
design with the exception of the boric acid evaporator and the radwaste
evaporator.
These two evaporators are in the final stages of beir.g made
operable and testing.
In the interim, a vendor resin system (covered by
a 10 CFR 50.59 review) has been used for water cleanup.
Operability is
not imminent for the licensee's volume reduction system (incinerator),
which involves primarily solids but also has provisions for treating liquid
in the form of contaminated oil.
No violations were identified.
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5.
Startup - Nonradioactive Process and Effluent Streams Checked for
Unanticipated Radioactivity
The licensee has established a progrr.m for gamma isotopic analysis of
quarterly samples from normally not.adioactive process and effluent
streams including the auxiliary steam system, station heating system,
diesel generator cooling system and the makeup demineralizer system.
No detectable activity has been identified.
Inspection Reports No. 50-454/85037; 50-455/85041 cover an occurrence
involving a recent identification by the licensee of slight contamination
(apparently from Unit-1) on vendor supplied resins used to purify flush
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water in Unit 2 piping systems, in preparation for preop testing.
6.
Exit Interview
The inspector summarized the scope and findings of the inspection with
licensee representatives (Section 1) at the conclusion of the inspection
on August 29, 1985.
The inspector discussed the likely informational
content of the inspection report with regard to documents or processes
reviewed by the inspector during the inspection. The licensee did not
identify such documents or processes as proprietary.
Licensee representatives acknowledged the inspector's identification of a
violation to follow adequate procedures and a violation of technical
specification requirements,
These matters were discussed in subsequent
telephone conversations with various licensee representatives on
September 3, 5, and 20.
On September 20, the violations were reaffirmed.
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