ML20245K274
| ML20245K274 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 08/03/1989 |
| From: | Garcia E, Hooker C, Andrea Johnson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML20245K259 | List: |
| References | |
| 50-344-89-18, IEIN-87-020, IEIN-87-20, NUDOCS 8908180381 | |
| Download: ML20245K274 (9) | |
See also: IR 05000344/1989018
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V. S. NUCLEAR REGULATORY COMMISSION
REGION V
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Report No.
50-344/89-18
Docket No.
50-344'
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Licensee:
Portland General Electric Company
121 S.W. Salmon Street
Portland, Oregon 97204
Facility Name: Trojan Nuclear Plant
Inspection at:' Portland and Rainier, Oregon
Inspection Conducted:
July 12-14 1989
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Inspectors:
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E. A Ho e
1 Facilities Inspector
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A. D. Johns
, Regional Enforcement Officer
Dfite' Sighed
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Approved:
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E. M. Garcia, Acting Chief
Date' Sigried
Facilities Radiological Protection Section
Summary:
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Areas Inspected:
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This was a special, unannounced inspection of an unresolved item
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(50-344/89-07-04) concerning the licensee's high: pressure hydrogen
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and nitrogen storage facility at the Trojan Nuclear Plant.
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addition the inspection included a review of the licensee's
evaluation and implementation of recommendations associated with NRC
Information Notice (IN) 87-20, Hydrogen Leak in Auxiliary Building,
dated April 20, 1987.
Inspection procedures 30703 and 92701 were-
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addressed.
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b.
Results:
One potential safety problem associated with. bulk storage of
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hydrogen on the roof of the control building had not been
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identified, evaluated or resolved as a result of the licensee's
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review associated with NRC Information Notice 87-20.
In addition,
the licensee's review and evaluation of the matters discussed in the
Information Notice were narrow in scope and not timely in completion.
Accordingly, one violation of 10 CFR 50, Appendix B, Criterion XVI
was idectified, paragraph 2.
{q90818038 <.
890803
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DETAILS
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- 1. . Persons Contacted
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- Lice'nsee
- D. WL Cockfield, Vice President, Nuclear
. C' P. Yundt, General Manager, Trojan
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2 *A.L N. Roller, Manager, Nuclear 71 ant Engineering -(NPE);
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R. M. Nelson, Manager, Nuclear Safety & Regulation' Department (NSRD)
- D.;R. Swanson, Manager, Nuclear: Safety Branch-(NSB)
- M..W. Hoffmann, Branch Manager, Mechanical Engineering
S. A.'Bauer,-Branch Manager, Nuclear Regulation
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D. W. Swan, Manager,-Technical Services'(TSM)
- W. 'J. Williams, Jr.,' Compliance Engineer
A. P. Corral, Nuclear Safety Engineer-
J. D. Guberski, Compliance Engineer
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D. R. Pearson, Specialist III, Nuclear Operations
M. H. Malmros, Supervisor, Instrument _ & Control Maintenance
'G'; Van'Bladeren, Supervisor, Mechanical Maintenance Engineering
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.W. Monroe, Systems Engineer
NRC Resident Inspector
jR. C. Barr , Senior Resident Inspector
~* Denotes individuals' attending the exit interview on July 14, 1989.
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.In additien to the individuals noted above, the inspectors met and held
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discussions with other' members of the licensee's staff.
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- 2.
Followup (92701)
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Background
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dated May 23, 1989, describes several
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Inspection' Report No. '50-344/89-07,
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rNRC Region.V concerns regarding potential safety problems with the-
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- (seismic Class II design) on the roof of the control room.
Concerns sere
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also raised with the location of the hydrogen system's fill station that
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was' located on.the exterior of the auxiliary building wall. The
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potential safety problems included:. (1) The potential for introducing an
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explosive or flammable gas mixture of hydrogen into the control room via
the control room ventilation system; (2) nitrogen leakage into the
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control room ventilation system that could cause asphyxiation of the
operators; (3) detonation of a hydrogen tank resulting in damage to the
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roof of the control room that could-have an effect on the performance of
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safety-related equipment; and (4) an explosion of the hydrogen delivery
truck that could result in damage to safety-related components in the
auxiliary building in the vicinity of the fill station. The potential
safety problems were identified based on the guidance provided in EPRI
NP-5283-SR-A., Special Report, September 1987, Guidelines for Permanent
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BWR' Hydrogen' Water Chemistry Installations-1987 Revision;
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indicated that the NRC was reviewing this EPRI/BWROG topical report. As.
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a' result'of these potential safety: problems, the NRC issued IN 89-44,
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l Hydrogen Storage on the Roof of the Control Room, dated April-27, 19894A
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- Chronology?of Events-
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Based'on a review of licensee records,L the-inspectors made the following
observations:
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The licensee's Corporate Office in Portland, OR, received IN 87-20 f
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on May 1, 1987, and forwarded it to the NSRD, also of the Corporatef
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Office; for review. An individual (0ERP Coordinator) in the NSB of.
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'the NSRD that was assigned the responsibility for the initial review
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land coordination of such documents, initiated Operational Assessment'
ReviewForml(0AR)87-29.
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The OERP Coordinator completed Part A,. Sections I and II, of 0AR
87-29 on May 2, 1987, marking: II.A. to note that IN.87-20 was
applicable to Trojan;Section II, item C " Conditionally
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Significant;" II.F.
" Investigate and recommend corrective action,
if any" and provided the following comment " Recommend that NPE
verify that Trojan's design-precludes excess hydrogen accumulation
in the Control / Aux Building / Fuel Building complex. The proper
sizing'of the excess flow valves shown on P&ID M-232/Rev 23 in
combination with adequate building ventilation would appear to
alleviate the. problem at Trojan." Item II.G. " Evaluation Priority"
assigned a target due date of July 3,.1987, and item II.H. assigned
NPE as the evaluation ~ action group. On May 3, 1987, the NSB Manager
approved the initial review and forwarded 0AR 87-29 to NPE, located
in the Corporate Office
NPE completed their evaluation (Part A,Section III and Part B) of
OAR 87-29 and submitted a request for design change (RDC), Startup
No.74,,datedOctober7,1987,andmemorandum(ANR-1246-87M), dated
October 8, 1987, with their recommendations to NSRD.
The memorandum (ANR-1246-87M) recommended that PGE 1012, Fire
Protection Plan Program Description, be revised to include the
effects of a hydrogen gas supply line leak.in the Auxiliary and Fuel
Buildings. The memorandum noted that the reason for the revision
was that PGE-1012 did not adequately address the possibility of
leaking hydrogen building up to flammability limits (4-75 percent by
volume). The memorandum also stated:
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" Evaluation of 0AR 87-29 concluded that ventilation in rooms
carrying hydrogen lines in the Auxiliary / Fuel Buildings is
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inadequate for the existing hydrogen gas supply excess flow
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valve (GS-037, -038, -162) closure setpoint.
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For example, ventilation in the volume control tank (VCT) room
is only 300 cubic feet per minute (cfm). Excess flow valve
closure setpoint is 600 standard cubic feet per minute (scfm).
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Flammability limits could:be. reached very quickly if a leak.
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. The 600 scfm flow rate was subsequently determined to be. incorrect,
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as discussed later in this report.
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The memorandum furti,+r ,uoted from the Standard Review Plan
-(NUREG-0800):
" Hydrogen lines in safety-related areas should be either'
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designed to Seismic Class 1 requirements.. or sleeved such that
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the outer pipe is directly vented to the outside, or should be
equipped with excess flow valves so that in case of a line'
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break the hydrogen concentration in the affected areas will not-
. exceed 2. percent."
.0AR (Part B)' Evaluation Criteria Checklist,Section III.B., states:
L"Could the identified problem:... Item 7. Degrade the facilities'
' fire protectionLprogram or fire-fighting capability?... Item 13.
' Result in unsafe' conditions not readily identifiable to Plant
Operators."-
These were marked yes.
RDC, Startup No. 7.4, recommended that: (1) to increase the
ventilation in the rooms carrying hydrogen lines in'the
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, % Auxiliary / Fuel. Buildings; or (2) replace hydrogen gas system excess
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. flow valves <that have'a lower closure set point and (3) install-
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' rooms carrying hydrogen. lines-to detect hydrogen leakage.
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The. Manager, NSRD approved 0AR 87-29 on November 19, 1987, and
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cforwarded it to the TSM at the Trojan Plant for review and approval.
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The TSM reviewed the 0AR package and returned it to NPE on November
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x25,11987, with the following note attached:
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"I see this as~a case.of over correcting for a potential
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problem of low probability and questionable safety concern.
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Need exists as I see it to look more closely for a cost
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effective solution."
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The OAR was reassigned to NSRD and, on December 8, 1988, an
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-individual from the Nuclear Safety group signed off as completing
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the re-evaluation of 0AR 87-29. This subsequent evaluation
recommended: (1) to delete the previous recommendation to increase
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the ventilation flows; (2) instead of replacing the hydrogen gas
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supply excess flow valves, install a new excess flow valve in the
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hydrogen line on the roof of the Auxiliary Building that supplies
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the VCT; (3) delete the previous recommendation to install hydrogen
sensing equipment in the Auxiliary / Fuel Buildings, since the system
engineer performs daily reviews of hydroren tank pressures; and (4)
revise PGE-1012 as previously recommended.
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The final approval process for 0AR 87-29 was completed and signed-
off_by the Vice President, Nuclear, on April 4, 1989. The target'
due date to revise PGE-1012 was' July l', 1989, and the target due
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date to install the new excess flow control valve was July 1, 1990.
Based on the above review, interviews with the individuals that performed
0AR 87-29 reviews and evaluations, and other document reviews, the
inspectors made the following additional observations:
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The individual that initiated 0AR 87-29 and performed the screening
(Attachment A, Sections I and II) informed the inspectors that: (1)
the scope of his review consisted of the topic addressed in IN 87-20
only and did not, and typically would not, include any other
documents such as those referenced in IN 87-20 (NUREG/CR-3551,
ORNL/N0AC-214 and EPRI/BWROG topical report, 1987 revision); (2) his
recommendations were made to stimulate interest in the review and
evaluation process; (3) his recommendation, to verify that Trojan's
design precluded excess hydrogen accumulation in the
Control / Auxiliary Building / Fuel Building complex from hydrogen
lines that may be routed through these areas, was based on personal
knowledge of the plant; (4) the control room was not considered
since there were no hydrogen lines in that area; (5) the Control
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Building was listed because he did not know for sure that hydrogen
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lines-were not routed through parts of this area; and (6) hydrogen
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storage on the roof of the control room was also not considered
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since storage was not the topic addressed in IN 87-20.
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NPE management staff informed the inspectors that the OAR evaluation
target due date (July 3,1987) was changed due to their involvement
in refueling outage activities.
The individual that completed the initial evaluation informed the
inspectors that: (1) the scope of his evaluation was based on the
topic addressed in IN 87-20, guidance in the Standard Review Plan
(NUREG-0800), information in the FSAR, system drawing, a walk down
of the hydrogen system's line routing (, and review of PGE-1012; (2)
the documents referenced in IN 87-20 NUREG/CR-3551,ORNL/N0AC-214
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and EPRI/BWROG topical report, 1987 revision) were not reviewed; and
(3) the control room was not a concern since no hydrogen lines were
routed through this area.
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The inspectors were also informed by this individual that the value
of 600 scfm, used in his evaluation to determine the flammability
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mixture in the VCT room, was based on information obtained from the
model number of one (middle valve) of three excess flow control
valves in the hydrogen supply manifold. The drawing he used only
listed one model number and he assumed that the other two valves had
the same flow rates, since their model numbers were not listed.
Based on the interview with cognizant NPE staff, the inspectors were
informed that the 600 scfm was the shut off flow for the excess flow
control bypass valve (GS-162) in the supply man 1 fold located on the
roof of the control room. This valve was normally isolated during
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routine operations and only used during filling of the turbine
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, generator's hydrogen cooling system. The normal operation' of the
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hydrogen supply system was through excess control valves GS-037 and
GS-038 with a nominal flow rate of 25 scfm and shut off flow at' 75
scfm_. 'Both of these valves supplied the header to the VCT and the
generator's cooling system.
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Based on discussions with the individuals that completed the OAR
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87-29 review', it appeared that they did not realize prior to the
Chemistry Team Inspection the 600 scfm flow rate was limited to the
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bypass flow path only.
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~ The TSM informed the inspectors that his request for a re-evaluation
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of 0AR 87-29 was based on his engineering judgement that: (1) the
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initial evaluation was'not thorough based on his knowledge of the
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plant systems and areas and (2) to increase the ventilation in the
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VCT room would be a very difficult and. costly task. The inspectors
were also informed that he did not consider hydrogen storage because
the OAR did not address it.
Based on interviews with cognizant NPE and NSRD staff, the licensee
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could not confirm where the OAR resided during the period of
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November 25, 1987, to December 8, 1988. The individual that
completed the re-evaluation informed the inspectors that he may have
had the OAR in his possession; however, he was not positive.
The individual that completed the re-evaluation informed the
inspectors that: (1) the scope of his evaluation was based on the
topic addressed in IN 87-20, guidance in-the Standard Review Plan
(NUREG-0800), information in the FSAR, system drawing, and review of
PGE-1012; (2) the documents referenced in IN 87-20 (NUREG/CR-3551,
ORNL/N0AC-214 and EPRI/BWROG topical report, 1987 revision) were not
reviewed and (3) that any leakage of hydrogen into the VCT room was
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not considered to be a significant safety problem, since there was
no ignition source in the room and the VCT was designed to seismic
Class I requirements.
Based on an examination of. licensee diagrams, the inspectors noted
that the hydrogen supply control valves were exterior to the VCT
room and appeared to have been hard piped to the VCT within the
room.
In addition, the level indicating units and control valves to
and from the VCT were also exterior to the room. The VCT was also
noted to be the only tank in the room and appeared to occupy a major
portion of the room's volume,
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Based on the above observations and interviews with NPE and NRSD
management, it appeared that the the documents referenced in IN 87-20
(NUREG/CR-3551, ORNL/NOAC-214 and EPRI/BWROG topical report, 1987
revision) were not reviewed by any of the persons responsible for the
reviews and evaluations associated with OAR 87-29. The initial review
and evaluation of the OAR appeared timely; however, the re-evaluation
appeared not to have been performed in a timely manner. One would
perceive that a matter originally considered to be conditionally
significant, a potential fire hazard, and could result in unsafe
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conditions not readily identifiable to plant operators would have
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received a more timely re-evaluation.
These matters were discussed with the licensee's staff during.the
inspection and at the exit interview on July 14, 1989. The inspectors
observations were acknowledged by the licensee. The inspectors were
informed that improvements.have been made in their Commitment Control
System to reduce delays in the 0AR review process.
The inspectors were also informed by the management staff and the Vice
' President, Nuclear, that since the referenced EPRI report was published
for BWR Plants, this document and other such documents for BWRs would not
receive the attention normally given to PWR documents. The licensee's
management staff stated that they believed their reviews and evaluations
were consistent with the subject matter presented in IN 87-20 and that
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the matter was'not considered to be a significant safety problem.
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Based on review of the concerns identified during the Chemistry Team
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Inspection _on April 17-21, 1989, personnel interviews, observations
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during this' inspection (50-344/89-18), and in-office review of documents,
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the inspectors made;the following additional observations:
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Prior to a recent change in the licensee's hydrogen storage
. facility, the hydrogen and nitrogen storage system was found as
. described in the UFSAR. Trojan's Design Base Document'(DBD) No. 30,
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Control Building-Ventilation Systems, dated September 16, 1987, did
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not. address the hydrogen storage facility's impact on the control
room. An independent design base review, completed by a contractor
on September 29, 1988, stated in DBD C3, Section 4.1 (2):
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" Gas storage tanks: All storage tanks were evaluated for
potential missile generation, and it was-determined that the H
bulkgastanksontheroofoftheControlBuildingwoulb
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produte the most significant and potentially damaging missiles
for safety-related equipment. These tanks have a relatively
high internal pressure (2,450 psig)..."
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...(see Appendix A, Open Item C3-0-06)."
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Appendix A, Item C3-0-06, Description, read, in part:
"For the following items, Trojan UFSAR information was used in
defining design bases in this document; however, no supporting
documentation was found (subsection 4.1.2):
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( b) - H and N tanks mounted on the Control Building roof
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cannot penetrate the 2 ft. 6 in, thick roof as stated on
UFSAR pages 3.5-16/17...."
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Following the Chemistry Team Inspection (performed during the licensee's
refueling outage), the licensee, on the evening of April 21, 1989,
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isolated the hydrogen storage tanks and installed oxygen monitors (for
any potential nitrogen inleakage) in the control room.
The Manager, NPE, informed the inspectors that during a meeting with
Bechtel during the first week of May 1989, the Bechtel representatives
informed PGE that, based on a cursory engineering evaluation, the
existing hydrogen and nitrogen storage facility's did not have any
adverse effect on the control room habitability (detonation, missiles and
line breaks); however, a detailed analysis to confirm this would be
costly. The licensee's staff informed the inspectors that rather than
expending money on;an analysis, they elected to rel_ocate the hydrogen
storage facility as'it could be incorporated into other modifications
already in progress and to assure that it will meet the EPRI guidelines.
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'No detailed, analysis was performed to determine whether or not the
previous hydrogen storage facility on the roof of the control building
. represented a. safety problem to the control room or other nearby safety
related equipment.
By' letter, dated May 5, 1989, the licensee, informed the Commission that
PGE was going ~to relocate the bulk hydrogen storage tanks from the roof
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of the' Control Building prior to reactor restart.
The letter also read,
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in part, that a complete evaluation, including the new storage facility
. location and any supporting analysis, would be submitted to the
commission by May 31, 1989.
During an Enforcement Conference held on May 12, 1989, at the NRC Region
V Office, related to security matters, the issue of hydrogen storage was
discussed. The licensee acknowledged the lack of timely action in
response to IN 87-20 but stated that'they believed the scope of their
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review was consistent with the topic addressed in the notice.
On May 31, 1989, PGE submitted their evaluation of the new hydrogen
storage system and the existing nitrogen system (on the roof of the
control room). No analysis ~ addressing the,old hydrogen system was
included in the report. The licensee also informed the Commission that
they would re-revaluate the hydrogen distribution system by July 14,
1989.
During the inspection the deportability of the hydrogen issue in
accordance with 10 CFR 50.73 requirements was discussed with the
licensee. At the exit meeting on July 14, 1989, the licensee informed
the inspectors that a report with their re-evaluation would be submitted
to the Commission by August 14, 1989, for information even though in
their view the matter was not reportable under the regulation.
The inspectors toured the area of the previous hydrogen storage facility
and the licensee's new storage facility. The inspectors verified that
the old storage tanks and fill station had been removed, as stated by the
licensee. The new hydrogen storage facility, includh g new tanks, was
located on the South side of the Cooling Tower. The hydrogen gas from
the new system to the plant was pressure reduced (2450 to 200 psig) and
supplied normal flow through two excess flow control valves with a shut
off flow of 75 scfm. The hydrogen supply lines were routed underground
from the Cooling Tower area to the South side of the Turbine Building,
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s#where they 'came out of the ground and ran over the Turbine Building roof
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to the roof of the Control Building. The hydrogen suppl
.this area was further pressure reduced (200 to 100,psig)y to the VCT from
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and flowed
.through another flow control valve with a cut off flow of 5.5 scfm. .The
licensee installed the new system under the provisions of 10 CFR 50.59.
10 CFR 50, Appendix B, XVI., Corrective Action, reads in part:
'" Measures shall .be established to assure that conditions adverse to
quality, such as failures, malfunctions, deficiencies, deviations,
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defective material,. and equipment and nonconformances are promptly
identified and corrected...'."
The failure to take prompt corrective actions for a potential safety
problem was identified as an apparent violation of 10 CFR 50, Appendix
B.,XVI (50-344/89-18-01).
3.
Exit Interview
-The inspectors met with the licensee representatives, denoted in
paragraph 1, at the conclusion of the inspection on July 14, 1989. The
scope and findings.of the inspection were summarized.
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The requirements of 10 CFR Part 50 Appendix B, XVI, were discussed. The
inspectors informed the licensee that the findings and observations made
during the inspection would be given further in-office review.
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