ML20236H862
| ML20236H862 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 10/30/1987 |
| From: | Delgeorge L COMMONWEALTH EDISON CO. |
| To: | Lieberman J NRC |
| References | |
| 3764K, IEB-79-14, NUDOCS 8711050007 | |
| Download: ML20236H862 (8) | |
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Commonwealth Edison -
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] Address Reply to: Post Office Box 767 l-A
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October 30, 1987 Ii Mr. James Lieberman Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
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Subject:
Zion Nuclear power Station Units 1 and 2 i
I Response to I&E Inspection Report Nos.
50-295/87-005 and 50-304/87-005 NRC Docket Nos. 50-295 and 50-304
Reference:
October 2, 1987 letter from A.B. Davis to J.J. O'Connor j
Dear Mr. Lieberman:
This letter concerns the safety inspection of activities at Zion Station conducted on March 2 through June 10, 1987, by C.F. Gill. The referenced letter indicated that the failure to properly install Zion's control room ventilation system appeared to be in noncompliance with NRC requirements. This issue was discussed on July 15, 19.87 during an Enforcement Conference held in the NRC Region III office.
The referenced letter also provided Commonwealth Edison with a Notice of Violation and proposed imposition of Civil Penalty for this event. This event was characterized as a Severity Level III violation and $50,000 civil penalty Violation was proposed. Commonwealth Edison Company's response to the Notice of Violation, along with a $50,000 check, is provided in the Attachment to this' letter.
In addition the referenced letter also requested that Commonwealth Edison conduct a review to ensure that the corrective action program developed is consistent with the concerns and actions outlined in paragraphs 5 (c) and (d) of the subject NRC Inspection Report. paragraphs 5 (c) and 5 (d) have been reviewed against the corrective action program outlined in the Attachment to this letter. The information and action plans described in these two documents are consistent with one another.
The failure to properly install the ventilation relief dampers in the Zion control room' ventilation system, and subsequent failure to properly evaluate and describe this deviation in Zion's updated FSAR, has logically produced broader questions regarding the current accuracy of Zlon's FSAR descriptions. The referenced letter requested that Commonwealth Edison Company provide the basis for having conddence that the control room ventilation system as well as other safety systems are in fact as described in the FSM or properly evaluated pursuant to 10 CPR 50.59.
Commonwealth Edison Company has carefully reviewed this matter and has concluded that there is little potential for existence of any additional significant deviations.
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4 J. Lieberman October 30, 1987 i
As described in'the Attachment, Commonwealth Edison's corrective' action program included a detailed walldown of the control room ventilation system. This walkdown was conducted with the specific objective of
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identifying any as-built discrepancies that could affect system safety function. Other than the initial construction deficiency that is the subject of this violation, no such discrepancies were found. This provides assurance that.the control room ventilation system is in fact as described in the FSAR.
Regarding other plant safety systems, our review has identified I
specific initiatives that have been completed, as well as ongoing surveillance programs, that provide a high degree of assurance that significant as-built discrepancies do not exist in those systems.
For example, the program completed in response to I.E.Bulletin 79-14 included detailed walkdowns and resolution of any as-built discrepancies in safety related piping systems.
For electrical and instrumentation systems, technical specifications require detailed, rigorous testing, generally in a manner that exactly replicates system functioning in accident modes. The application of such programs represents a significant difference between other plant systems and the control room ventilation system, and supports our determination that no additional actions are needed on those systems.
The referenced letter stated that the escalation and mitigation factors contained in the Enforcenant policy were considered and no adjustment has been deemed to be appropriate. Commonwealth Edison Company has also reviewed these factors and has concurred that no adjustment is appropriate.
However, there is additional information regarding the extensiveness of the corrective actions taken that Commonwealth Edison wishes to highlight.
j As fully described in the Attachment, Commonwealth Edison Company embarked on an extensive design review program on September 17, 1986. This was immediately following the initial identification and sealing of the misinstalled relief dampers. To date, this program has involved in excess of 1,000 man hours of effort.
After careful review, the modification program described in the Attachment hus been developed. Tnis program will involve an additional commitment of manpower and finances This design review and corrective 3ction program represents an aggressive approach to resolving Zion's main control rocxn HVAC deficiencies.
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october ~30, 1987
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l Please direct any further questions to commonwealth Edison's
. Department of Nuclear Licensing.
Very truly.yours, a
. Assistant Vice Pr sident
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. Attachments-
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'cc: Zion. Resident ' Inspector J.;A.'Norris:
A. B.'. Davis.- RIII.
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j ATTACHMENT ZION NUCLEAR POWER STATION RESPONSE TO NOTICE OF VIOLATION ITEM OF NONCOMPLIANCE As a result of an NRC inspection conducted during the period March 2 through June.10, 1987, a violation of NRC requirements was identified.
In accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions," 10 CFR Part 2, Appendix C (1987), the Nuclear Regulatory Commission proposes to impose a civil penalty pursuant to Section 234 of the Atomic Energy Act of 1954, as amended (Act), 42 U.S.C. 2282, and 10 CFR 2.205.
The particular violation and associated civil penalty are set forth below:
10 CFR 50.34(b) requires, in part, that the licensee submit a final safety analysis report that describes the facility.
10 CFR 50.59 requires, in part, that changes made to the facility as described in the finni safety analysis report be evaluated in accordance with 50.59(a) to determine, in part, if an unreviewed safety question exists, j
Figure 9.10.2-1 of the Zion Station Updated Final Safety Analysis Report (UFSAR) illustrates the design configuration of the control room j
ventilation system.
v contrary to the above, the control room ventilation system as described in Figure 9.10.2-1 of the UFSAR did not reflect the as-built system
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as required by 10 CPR 50.34(b). The system as-built contained a different damper configuration than that described in the UFSAR which resulted in unfiltered inleakage pathways. The deviation between the UFSAR and the as-built system was not evaluated in accordance with 10 CPR 50.59.
This is a Severity Level III violation (Supplement I).
4 Civil Fenalty - $50,000.
AD_HISSJON OR DENIAL OF THE ALLEGED VIOLATION Commonwealth Edison company admits the violation as described above.
REA. SONS FOR THE VIOLATIOM The most basic reason for this violation was the inadequate implementation of the original design intent of the main control room HVAC relief damper configuration. This design change, which occurre0 during the construction phase of Zion Station, evidently was implemented without sufficient communication between the construction crews and the engineering staff. Due to the construction / quality assurance practices during this time period, there is little information available to more fully illLtminate the detalls of this miscommunication.
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, However, since this design change occurred during' construction, a
~ documented evaluation under 10 CPR 50.59 was not performed, as would have been
'the case for a system modification after the plant became operational.
Commonwealth Edison Company's trigger for performing and documenting a 10 CFR 50.59 evaluation of a design change is the initiction of such a modification.
The absence of a modification package, and an associated safety evaluation, would in turn result in Zion's FSAR not being properly updated.
CORRECTIVE ACTION THAT HAS BEEN TAKEN AND RESULTS ACHIEVED 1.
Immediate corrective action following the discovery of radioactivity within the main control room on September 11, 1986, was to identify and seal the misinstalled relief dampers.
In addition, the integrity of the sealed dampers was verified through the use of a helium leak test. This process of investigation, leak identification, and immediate sealing of the leakage source occurred during the time period of September 12-16, 1986.
2.
Zion Station Commonwealth Edison's Station Nuclear Engineering Department (SN8D) and Sargent & Lundy Engineers initiated an extensive design /as-built review of the entire control room HVAC system. This effort was initiated on September 17, 1986. The purpose of this review was to determine if other design /as-built inconsistencies existed and to evaluate their potential safety significance.
This was an extensive effort eventually involving in excess of 1,000 man hours of both commonwealth Edison and Sargent & Lundy personnel. As discussed above this effort was initiated immediately following the
. discovery and closure of the source of inleakagc.
This effort resulted in the identification of several minor inconsistencies related to a few ventilation mixing boxes, mislabeled duct lines, or inaccurate piping and instrument diagrams. None of these deviations had any safety significance.
l 3.
However, the review /walkdown effort described above did identify a number of items that could potentially enhance the operation of the mein control room ventilation system. These issues are listed below:
a.
Redundant leak-tight isolation of the control room HVAC system from l
outside air sources and the adjacent Technical Support Center (TSC) HVAC system should be provided. This would preclude a single damper failure from causing a loss of the system's functional performance.
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b.
Eliminate potential unfiltered air leakage paths via the filter bank's and/or air handler drains.
I c.
Automatic isolation of the hot and cold lab supply fan duct work should be provided.
l d.
Rerouting of the main control room / adjacent area differential pressure instrumentation to more accurately measure the required pressure differential.
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CORRECTIVE ACTION THAT WILL BE TAKEN TO AVOID FURTHR9 VIOLATION As described above, the design review and walkdown effort identfied five major improvement goals for the Main Control Room HVAC System (PV).
Briefly, these goals are:
1.
Provide redundant isolation of the normal outside air path.
2.
Provide redundant isolation between the PV and adjacent OV ventilation Systems.
3.
Permanently seal the misinstalled relief dampers.
4.
Upgrade the quality of the PV differential pressure instrumentation.
5.
Bliminate any potential air in-leakage paths via various drain lines.
The specific modifications that will be installed to satisfy these goals are outlined below. A diagram of the PV system is provided to illustrate modifications a, c, e, and f.
a.
The control room HVAC system relief dampers will be permanently sealed off. This modification will remove the economizer mode of operation from the control room HVAC system. The TSC HVAC system will maintain its economizer cycle. Since both systems presently share the same outside j
suction path this duct work will have to be altered.
J b.
Check valves will be installed to eliminate the potential unfiltered air and leakage paths into the filter banks and air handlers via their drain systems.
i c.
The hot and cold labs supply fan will be isolated from the PV System.
l This modification will involve installation of a new 42" x 10" bypass duct l
connected to the outside air duct upstream of bubble tight damper OPCV-PV-39.
I d.
The present control room / adjacent areas pressure differential transmitter sensing lines lead from the control room to the auxiliary building and the TSC.
These sensing lines will be rerouted to traverse from the control room to the turbine building only. This modification will give a more accurate reading of pressure differential between the control room and its adjacent areas.
e.
Redundant isolation of the normal outside air path will be achieved by j
installing a 24" x 48" bubble tight damper on the outside air inlet to l
both PV air handling units. This will require that the PV make-up filter duct be disconnected from the outside air duct and reconnected to PV return duct.
l f.
Redundant isolation of the OV air handling units from the PV air handling l
units will be achieved by replacing the existing 48" x 60" damper
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OFCV-pV-11B with a single bubble tight damper in conjunction with the modification Cescribed in (c) above.
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_4-DATE WHEN FULL COMPLIANCE WILL BE ACHIEVED Implementation of the modification program described above is expected to be complete during the first quarter of 1989. Procurement and delivery of the bubble tight dampers is anticipated to be the limiting factor.
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