ML20082R468
| ML20082R468 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/09/1983 |
| From: | Pollard R, Weiss E UNION OF CONCERNED SCIENTISTS |
| To: | |
| Shared Package | |
| ML20082R474 | List: |
| References | |
| NUDOCS 8312130182 | |
| Download: ML20082R468 (6) | |
Text
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USNRC L
13 DEC 12 P12:14 UCS 12/9/83 0FFICE CF SECCETAF UNITED STATES OF AMERICA'f ag; g. SEtu.*:n~
rmr v 7 gg NUCLEAR REGULATORY 00rtilSSION BEFORE THE COMMISSION In the Matter of
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METROPOLITAN EDISON COMPANY
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Docket No. 50-289
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(Restart)
('Ihree Mile Island Nuclear
)
Station, Unit No. 1)
)
UNION OF CDNCERNED SCIENTISTS RESPONSE TO GEU LETTER OF DECEMBER 6, 1983, REGARDING EMERGENCY FEEDWATER FLOW INSTRUMENTATION Introduction On December 6,1983, counsel for GPU transmitted to you a docment which it characterized as "potentially relevant and material to matters under j
adjudication in the plant design and procedures phase" of the mI-l restart t
proceeding.
The docment is a letter frm H. D. Hukill, Director of MI-1, to l
the NRC, dated November 23, 1983.
The letter discloses that the emergency l
feedwater flow instr ments installed at MI-l to corply with the short-term
" lessons learned" requirements do not meet NRC's criteria or GPU's commitment in
[
the restart proceeding.
Il essence, GPU requests an exmption fran those requirements, although its subnission obscures this, as we will describe below.
There is no justification for granting such an exemption and UCS therefore urges that you not permit the plant to operate without accurate feedwater-flow instrmentation.
8312130182 831209 i
PDR ADOCK 05000289 G
,. Background The NRC's 21-2 [assons tearned Task Force noted that "the need for an energency feedwater systen of high reliability is a clear lesson learned from the MI-2 accident.A!
The Task Force recomnended, among other things, that safety-grade indication of emergency feedwater flow be provided for each steam generator and that such instrumentation be installed by January 1,1980. ! This requirement was later clarified to require, for mI-l and other Babcock and Wilcox plants, two energency feedwater flowrate indicators for each steam generator.
The implementation schedule was extended such that final design information was to be subnitted to NRC by January 1, 1981, and installation completed by July 1, 1981. !
During the restart hearing, the. NRC Staff testified that: 1) each instrunent should have "an accuracy on the order of 110%," 2) the licensee had comnitted to installing two safety grade sonic flow devices on each of the two emergency feedwater pipes, and 3) the licensee indicated that these new flow devices would have "an accuracy of better than 15%."A/ The Staff concluded, on that basis, that MI-l was in canpliance with all the short-term requirements applicable to the energency feedwater flow indicators, subject only to the l
subnittal of environmental qualification certification.5/
l' In a letter dated May 24, 1983, TU advised the NRC Staff that two of the four installed energency feedwater sonic flow devices would be replaced with l_/
NUREG-0578, "mI-2 Iassons Learned Task Force Status Report and Short-Term Recomnendations," July 1979, p.10.
2/
Id., pp. 11, A-32, and B-2.
3_/
NUREG-0737, " Clarification of WI Action Plan Requirements," Novenber 1980, pp. II.E.1.2-4,
-5.
4/
Staff Ex. 1, NUREG-0680, " mI-l Restart," June 1980, p. C8-39.
l 5/
Id., p. C3-40.
See also NUREG-0680, Supp. No. 3, April 1981, pp. 38-39.
L
, differential pressure transmitters.
On August 25, 1983, GPU notified the NRC Staff that further testirg had shown the remaining sonic flow devices to be unsatisfactory and that, by restart, all of the sonic flow devices would be replaced with differential pressure transmitters.
In a letter dated September 22, 1983 (copy attached), the NRC Staff informed GPU that the change to differential presnure transmitters was acceptable to neet the short-term lessons learned requirements pertaining to emergency feedwater flow indication.6/
Discussion In its November 23, 1983 letter, GPU discloses that its August 25, 1983, assurance that the differential pressure instr m ents for measuring emergency feedwater flow."are reliable and accurate and are designed to monitor the full range of systs flow requirements," is incorrect.
Tests have disclosed that with mergency feedwater flow less than 100 gpm, oscillations cause the indicated flow to be inaccurate by more than 10%.
(GPU does not say how far outside the +10% accuracy requirement the flow indication lies.)
Nevertheless, GPU concludes that the emergency feedwater flow systs as currently installed and tested at IMI-l "is acceptable and meets the requirements of NUREG 0737 and our conmitment as reflected in the Partial Initial Decision of December 14, 1981."
6/
We note the sharp contrast between the Staff's letter approving the differential pressure instr ments and its earlier approval of the sonic fl3w devices in NUREG-0680, p. C8-39, 40.
'Ibe earlier approval describes the sonic flow devices in great detail, which creates the impression that the Staff reviewed the design. The recent approval of the differential pressure transmitters provides neither a description of the design nor a basis for the Staff's approval. However, this contrast may not be significant because tle earlier Staff testimony in NUREG-0680 is little more than a rewording of the material supplied by GPU!_ SdeJ.a.c. Ex.1, Report in Response to NIC Staff Reconmended Requirments for Restart of Three Mile Island Nuclear Station Unit 1, p. 2.1-23.
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. Paragraph 1029 of the Licensing Board's December 14, 1981 Partial Initial Decision is as follows:
The original EEW system design did not have any provision for indication in the control rom of mergency feedwater flow.
Safety-grade, redun-dant indication of EEW flow to each steam generator will be provided in the control rom prior to restart.
Licensee has comnitted to perform a functional test of the new EEW flow instrumentation prior to restart.
Basal upon the Staff's review of the Licensee's design for providing safety-grade EEW flow indication in the control room and on the infor-mation that the flow transducers are qualified for operation in the assumed environment from a postulated main steam line break in the Intermediate Building, the Staff has concluded that Licensee is in compliance with the NUREG-0578 recomnendation, in item 2.1.7.b, for emergency feedwater flow indication to the steam generators. The Staff will verify that the flow devices are installed and suitably qualified prior to restart.
(Citations mitted.]
Based on the information provided in GPU's Novmber 23 letter, UCS concludes that the short-term lessons learned requirements for emergency feedwater flow indication have not been met at M I-1.
The basis for this conclusion follows.
GPU claims that its admittedly inaccurate emergency feedwater flow-instrunentation does "not affect the functional capability of the EEW system or the ability of the operator to take proper action."
We agree that lack of reliable flow indication does not directly affect the functional capability of the mergency feedwater system, but it can (and during the 'IMI-2 accident did) affect proper operator action.
Durirg the WI-2 accident, the lack of EEW flow indication did not, in fact, affect the functional capability of the EEW system.
However, there was no EEW flow initially because two valves were closed, and the lack of EEW flow instrumentation delayed proper operator action for about 12 minutes.
GPU also claims that, if the EEW system is automatically initiated,
" accuracy of flow rate is not necessary at low flows." GPU apparently overlooks the fact that the EEW pumps are cooled by that flow.
If the FEW flow control'
. valves are closed, a failure of the pump recirculation flow paths could require prompt operator action to prevent failure of the EEW pumps.
During manual control of EEW flow, GU claims that the operator's attention would be focused on the indication of steam generator -level and pressure, not on EEW flow indication.
Again GPU's memory is short.
During the mI-2 accident, the operators focussed their attention on a few instrtnents and ignored others, to the detriment of core integrity.
Does GPU now propose to stand on its head the lesson learned that operators should not focus their attention on only a few instruments?
GPU's claim that the operators do not need to use EEW flow indication to control steam generator level also directly contradicts the lessons learned requirements. 'Ihe requirement to install two EEW flow indicators for each steam generator in B&W plants like mI-l stenmed fran the need "to provide the capability in the control room to ascertain the-actual performance" of the emergency feedwater system.E This requirenant was relaxed, for Westinghouse and Combustion Engineering plants, to the extent that only one EFW flow indicator for each steam generator was required "for PWRs with U-tube steam generators becaure flow indication is of secondary importance in assuring steam generator coolirg. capability for steam generators of this design."W Because TMI-l uses a once-through steam generator design, EEW flow is of primary importance.
GPU's proposal also ignores the experience of the mI-2 accident in another respect.
Durirg the MI-2 accident, the operators ignored indications of extremely high temperatures in the core because they knew the instrtments were not safety grade and thus potentially unreliable.
Now GPU proposes to operate y
NUREG-0737, p. II.E.1.2-4.
. _8/. g L
. TMI-l with unreliable EFW flow indication and " assist the operators in understandirg how the EEW flow devices are expected to perform under various EPd flow conditions," i.e., inaccurately.
Conclusion The short-term lessons learned of NUREG-0737 specifically require for B&W reactors precisely what TMI-l does not have: emergency feedwater flow instrumentation meeting strict, detailed performance criteria to ensure that operators can rely on them.
These requirements can not be met by installing faulty instruments and telling the operators to ignore them.
To even suggest such a response is disingenuous in the extreme.
Because GPU has failed in two attempts over a period of several years to design an accurate, reliable EEW flow indication system, it is reasonable to conclude that this further demonstrates the licensee's technical incompetence.
Since the industry-wide deadline for installing this instrumentation was July 1, 1983, we assume that all other operating plants have met the pertinent requirements. Were is no reason to exempt 'IMI-1.
Werefore, 'IMI-l should not be permitted to restart until it also complies with this "short-term" requirement.
Respectfully subnitted, L
b h j)pf EllyffR. Weiss
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General Counsel h
e Robert D. Pollard Nuclear Safety Engineer Dated: December 9, 1983
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WASHINGTON, D. C. 20555 Q'~off September 22, 1983 Docket No. 50-289 Mr. Henry D. Hukill Vice President GPU Nuclear Corporation P. O. Box 480 Middletown, Pennsylvania 17057
Dear Mr. Hukill:
By order dated August 9,1979, the Commission required, in part, that GPUN provide indication in the THI-l Control Room of emergency feedwater system (EFW) flow to each steam generator prior to any subsequent restart.
To satisfy this requirement, GPUN committed to install two safety-grade sonic flow devices on the flow path to each steam generator to provide Control Room indication of EFW flow. This commitment was reviewed and found acceptable by the NRC staff as documented in the TMI-l Restart Safety Evaluation (NUREG-0680) pages Cl-5 and C8-39, 40 and NUREG-0680, Supplement 3 pages 38-39.
Recently by letters dated May 24, 1983 and August 25, 1983, you advised us that, due to signal interference problems between the sonic flow devices and other unsuccessful test results, you have decided to remove the sonic flow devices and replace them with differential pressure transmitters. We have received the information provided in your submittals and, based upon that review, we conclude the changes you propose satisfy the requirements of Part 2 to NUREG-0737 Action Item II.E.1.2 " Auxiliary Feeawater System Automatic Initiation and Flow Indication" and are therefore acceptable.
- incerely,
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Z Job F. Stolz, Chief Opdrating Reactors Branch #4 1 vision of Licensing cc:
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