ML20148K114

Forwards CRGR Staff Summaries of Proposed Bulletin Re Thinning of Pipe Walls in Nuclear Power Plants & Proposed Long Term Resolution to IGSCC Problem in BWR Piping.Meeting 114 Scheduled for 870507

ML20148K114
Person / Time
Issue date:	05/06/1987
From:	Conran J NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Bernero R, Jordan E, Sniezek J NRC, Office of Nuclear Reactor Regulation
Shared Package
ML20148K054	List: ML20148K050 ML20148K058 ML20148K074 ML20148K080 ML20148K087 ML20148K093 ML20148K114
References
FOIA-87-714 NUDOCS 8803310015
Download: ML20148K114 (9)

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1. %, UNITED STATES 8 o NUCLEAR REGULATORY COMMISSION r., a w AsmNGTON. D. C. 20666

, g, ,/ May 6, 1987 MEMORANDUM FOR: Edward L. Jordan, Chairman, CRGR Robert M. Bernero, MNSS James H. Sniezek, NRR Denwood F. Ross, RES T. T. Martin, RI ,

Joseph Scinto, OCG l

THRU: John E. Zerbe Assistant for CRGR Operations, AE00 1

FROM: James H. Conran l Senior Program Manager, AEOD -

SUBJECT:

SUMARY AND ISSUE IDENTIFICATION CRGR AGENDA ITEMS, MEETING NO. 114

) Enclosed for your information and use are CRGR staff susunaries for the following CRGR review items:

(a) Proposed Bulletin, "Thinning of Pipe Walls in Nuclear Power Plants" 1

(b) Proposed Long-Term Resolution to the IGSCC Probles in BWR Piping I These matters are scheduled for CRGR review at Meeting No.114 on Thursday, May 7, 1987 in Roos 6507 MNBB at 1:00-4:00 p.m.

J Conran CRGR Staff

Enclosures:

As stated 8803310015 880324 PDR FOIA WEISS87-714 PDR E/A?

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Summary and Issue Identification i

I CRGR Agenda Item - Meeting No. 114 May 7, 1987 IDENTIFICATION Proposed IE Bulletin 87-xx, "Thinning of Pipe Walls in Nuclear Power Plants" OBJECTIVE The staff has requested that CRGR review and recommend to the EDO approval for issuance of a bulletin requesting all holders of operating licenses or construction permits to provide information concerning their programs for monitoring the thickness of pipe walls in condensate, feedwater, steam, and connected high energy systems and in safety-related systems fabricated of carbon steel.

BACKGROUND The package submitted for review by CRGR was transmitted by memorandum dated April 10, 1987 J.M. Taylor to J.E. Zarbe; that package included the following documents:

1. Proposed IE Bulletin 87-xx, "Thinning of Pipe Walls in Nuclear Power Plants"

2. Response to Section IV.B of the CRGR Charter

3. Cost-Benefit Analysis for Proposed Bulletin

4. Memorandum, dated April 2,1987, E.L. Jordan to Distribution, "Licensee Secondary Pipe Wall Thinning Monitoring Programs" DISCUSSION / ISSUES The proposed bulletin is an NRC response to the Surry pipe rupture event.

It's purpose is to provide the staff with better information on which to base a decision regarding whether it is necessary to impose additional requirements for in-service inspection / monitoring of pipe wall erosion. As noted in Background Item 4. above, industry attention to this issue subsequent to the Surry incident in general has been quite substantial, but there remain questions and concerns regarding the efforts of specific licensees. In this regard:

1. The Committee may wish to discuss with the staff what is known currently about ongoing licensee actions resulting from industry initiatives (e.g.,

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INPO, NUMARC, EPRI,etc.) in order to determine whether generic or plant

[ specific action by NRC is more appropriate in the current circumstances.

Generic action, as proposed by the staff here may interfere with and/or duplicate licensee actions already underway, and could be interpreted as implicit criticism that industry initiatives (that should be supported where possible) are inadequate. If only a few licensees are recalcitrant or deficient in their voluntary response to the problem indicated by the Surry incident, and they are already known, perhaps plant specific actions by NRC would be seen more clearly as supportive of the technical adequacy (as contrasted to the enforceability)of industry initiatives.

2. The Committee may wish to pursue the following specific questions regard ing the alternative cost-benefit analysis provided in connection with this proposal:

a. In view of the significant industry efforts initiated following the Surry event to study further the problem of pipe wall thinning in the systems / configurations of concern to NRC in proposing this action, is it reasonable to assume that the additional monitoring requirements anticipated in the staff's analysis will actually contribute to an 8 % reduction in thinned wall pipe rupture frequencies in the future? (See Background Item 3. at p.4.) That assumption drives the staff's cost-benefit calculation strongly toward the highly favorable conclusions presented in the review l package. Use of a more realistic contribution (e.g., say 10%-20%)  !

would make the proposed action much more of a toss-up from the viewpoint of cost-benefit justification.

b. In their analysis of onsite benefits, the staff assumes that every single phase rupture results in a single fatal injury. (See Back-ground Item 3 at p.5.) Even granting that this estimate is reason- i able, the Committee may wish to discuss with the staff the appro-priateness of including this consideration in their cost-benefit l analysis, in a manner that suggests strongly that, as a matter of policy, it has been decided finally that NRC is responsible for regulating such non radiological occupational safety hazards.

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'.' Summary and Issue Identification

, y CRGR Agenda Item - Meeting No.116 June 10, 1987 IDENTIFICATION Proposed 50.54(f) Information Request Regarding Loss of Decay Heat Removal Function at PWR's with Partially Orained Reactor Coolant Systems (Mid-Loop Operation)

OBJECTIVE l l

The staff has requested that the CRGR review, on an accelerated basis, a proposed 50.54(f) information request in order to more fully evaluate the "loss  !

of RHR during mid-loop operation" syndrome which has occurred (and in some cases, reoccurred repeatedly) 37 times now at 15 operating nuclear power  !

stations. Following the latest mid-loop event at the Diablo Canyon facility on April 10, 1987, in which boiling occurred in the core 85 minutes after loss of l decay heat removal function in a partially drained and depressurized reactor coolant system and with containment integrity broken, the staff has come to regard the mid-loop syndrome as a safety-significant unanalyzed event that requires increased attention on an accelerated schedule. Accelerated treat-ment by CRGR, and appropriate response by licensees in 60 days, will allow the staf f to complete the accelerated review process currently envisioned by April 30, 1988, i

BACKGROUND

1. The document package submitted for review by CRGR in this matter was transmitted by memorandum dated June 2,1987, T.E. Murley to E. Jordan; i

.it included the following documents as enclosures: l

a. Attachment 1 "Response to Requirements for Content of Package Submitted for CRGR Review" i

b. Attachment 2 Proposed 50.54(f) Generic Information Request Letter, and enclosures as follows:

1. Enclosure 1 "Information Pertinent to Loss of RHR Systems While in Mid-loop Operation"

c. Attachment 3 NRC Information Notice 87-37, "Loss of Decay Heat Removal During Low Reactor Coolant Level Operation"

d. Attachment 4 Table 1 "Chronology of 37 Loss of DHR Events Attributed to Inadequate RCS Level"

,,- 2. Related documents, not transmitted to CRGR with the review package by the sponsoring office, but considered by the CRGR staff in connection with the preparation of this issue sheet, included:

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a. Memorandum, dated May 18, 1987, E. Jordan to T.E. Murley and E.S. Beckjord, "Loss of Decay Heat Removal Function at Pressurized Water Reactors with Partially Drained Reactor Coolant Systems"

b. AEOD Case Study Report, AE00/C503, dated December 1985, "Decay Heat Removal Problems at U.S. Pressurized Water Reactors" OISCUSSION/ ISSUES

1. The proposed 50.54(f) letter appears to go well beyond a mere information request. In effect, in its current form, it constitutes imposition of an unacknowledged backfit of a new staff position, resulting from a new inter-pretation of an existing regulation (i.e. , GOC-34). More specifically, the proposed information request requires of licensees assessments, analyses, operational procedures information, etc. , not heretofore required, in order for the staff to be able to conclude that there is reasonable assurance that the licensees will operate their facilities within approved design /

licensing bases. ,

The staff asks (in Background Item 1.b.1, at pp. 2-3) for extensive "descriptions" of: 1) circumstances and plant conditions involved in mid-loop operations, 2) instrumentation and alarms and other plant equip-ment used in mid-loop operations, 3) containment closure conditions observed by licensees during mid-loop operations, 4) procedural guidance pertinent to control of normal and off-normal plant conditions and the activities of operations personnel during during normal and recovery type mid-loop operations, and 5) the analysis bases for 3 & 4 preceding. In scope and content the "descriptions" requested do not differ much from the analyses of design basis events, and the procedures for dealing with them, that are currently required explicitly for licensing. The staff goes on to state (in Background Item 1.a, last sentence of paragraph 1) that such "descriptions" are now necessary to assure safe operation in this mode.

That is a regulatory posture / position that has never been taken before by the staff; the staff has not until now required review of such analyses and procedures "...to assure safe operation in this mode."

Clearly then, even though the proposed action does not involve any new requirements in the regulations, the staf f's interpretation of what licensees must do to demonstrate compliance with the existing regulations (e.g., GDC-34) has changed; and the staff has spelled out in the proposed infomation request package their new position on what is required minimally now to reasonably assure safe operation...(to be specific, extensive new analyses of this heretofore unanalyzed event / syndrome, and a new level of awareness among licensees of the safety significance of mid-loop operation as reflected in detailed, procedural guidance for operations personnel. Imposition of such a new position is a backfit under 10CFR50.109; and the burden is on the staf f to fully justify the backfit.

2. The staff states in Background Item 1.a (see paragraph 2) that licensees would be expected to supply detailed descriptions of plant conditions dur-ing mid-loop operation, procedures required for this mode of operation (including restrictions and analytical bases that apply), information on training for this type of plant evolution, etc.. . .all at a "minimal" cost.

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The Connittee should discuss with the staf f the basis for that estimate in view of the following statement in an AE0D evaluation of this same preblem (see Background Item 2.a. , at p. 2, paragraph 4):

"Generally, procedures for operation during modes 3, 4, and 5 are of an ad hoc nature, scant or even nonexistent. Similarly, procedures for recovery from a loss of DHR are not necessarily well thought out.

In addition, operators may not be trained in recovery from a loss of DHR. . . etc. , etc. , etc. "

Are the sponsoring office staff unaware of these AE00 assessments? Do they disagree with them? If not, what is the basis for estimating "minimal" costs for licensees who will obviously have to develop ti4 extensive analyses and procedures they are "expected" to provide in response to the proposed "request"? Did the staff coordinate with utility or other industry groups in developing the cost estimates provided to CRGR? If not, why not in an instance such as this in which those must directly impacted by the proposed action will not have the opportunity to ,

comment during a public comment period? In this same veir6 the Comm Stee may wish to discuss with the staff other detailed in-house %st enimat:s also made by AE00 in Background Item 2a. relating to this isrue, fpeci-fically, a) why were these cost estimates not provided to CNR in coraec tion with this review? On the basis of AEOD's look at this (ssee, what would be the cost involved for licensees to develop from scratch the extensive information requested in the proposed letter? What wou1c' bc +.he benefits, in general terms, with regard to reduction in ,: ore damase frequency and risk?

3. The Committee may wish to discuss with staff the relationshi3 of (his pro-posed action to USI A-45. In Background Item 2.a. , AE00 see01 to 'dMnt that it would be reasonable and feasible to integrate the 4alts w t2 air AE00 Case Study on loss of CHR in the mid-loop opvati6n mode (i.a. , Back-ground Ites 2.b.) with USI A-45. Has the sponsoring office st3ff c6asi-dered integrating the immediate proposed action, and any anticipated follow-on actions, with that USI? If not, why not?

4. The only real supporting infomation provided to CRGR in connectbn with this proposed action is the data in Table 1 (i.e. , Background Item 1.d.).

With obvious reference to the Table 1 data, the staff states in Background Item 1.b. (see p. 2, second sentence of last paragraph) the following:

"This topic has been addressed in numerous communications with the licensees. Yet, events continue to occur at a rate of several per year."

The implication is that there has been no improvement in the rate of occur-rence of mi& loop events as a result of previous regulatory actions of lesser impact (e.g. issuance of IN's, issuance of AE00 case studies, etc.);

so more drastic action is called for now in order to get proper licensee attention to a serious continuing problem. The data provided in Table 1, however, can be interpreted as indicating a general trend of improvement in some important aspects of licensee performance with regard to this probles, even among licensees who were serious repeat offenders in earlier years. For example, summarizing the data in Table 1 in terms of total events per year yields the following:

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Year Events /Yr 1977 1 1978 4 1979 2 1980 3 1981 2 1982 7 1983 5 1984 6 1985 3 1986 2 1987 2 (to date) 37 Total for PWR's, 1977-1987 Clearly, the peak rate of occurrence for mid-loop events of concern to the staff occurred in the 1982-1984 timeframe. The rate of occurrence has drop-ped off sharply since then; and it could certainly be argued that that decrease occurred in response to previous staff communications to the licensees. Further indication of responsiveness on the part of the licensees with regard to the staff's concern in these areas is the observation in the transmittal letter for this package that several licensees have already taken additional actions voluntarily in response to recent informal communications from the stoff on this topic.

Similarly, summarizing the Table 1 data in terms of events per station, with attention given also to year of occurrence, yields the following:

Facility No. of Events Year (s) of Occurrence North Anna 8 1982, 1983, 1984 Trojan 6 1977, 1978, 1981, 1984 Beaver Valley 5 1978, 1980 McGuire 4 1982, 1983 Sequoyah 3 1983, 1985, 1987 (115*F)

Zion 2 1984, 1985 (15?'F)

Sub-total 28 Millstone 1 1979 Sales 1 1979 Surry 1 1983 DC Cook 1 1984 ANO-2 1 1984 Catawba 1 1985 (175'F)

San Onofre 1 1986 (212'F)

Waterford 1 1986 (17L*F)

Stablo 1 1987 (220*F)

S@ ten 1 ~P Total PWR Evehis 37 i

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. .' From this presentation of the data, it is apparent that the great prepond-erance of events of concern to the staff in this matter (i.e. 76%) are accounted for by a relatively small number of licensees (i.e. six), who have experienced repetitions of mid-loop operation problems. This could reasonably be taken as indication of an attitude of sloppiness on the part of the operating staf f, or possibly indication of management problems, affecting only a few individual licensees. If so, these are the kinds of problems that more appropriately should be dealt with on an individual licensee or plant specific basis (to focus recognition of responsibility and accountability), rather than by penalizing all PWR licensees with a generic backfit action (that tends to distribute or dilute accountability).

With regard to the six licensees who have experienced repeat events, there is clear indication in the Table 1 data of significant improvement in per-formance. The most serious offenders from the viewpoint of repetitions of such events (e.g. those who experienced 4 or more events) have not experienced a problem during the last three calendar years. And even at the two stations in the repeat category where such events have recurred during the last three years, the data seems to indicate proper operating staff performance during the most critical period of mid-loop operation (i.e. , when decay heat levels were high enough to result in very high core core coolant temperatures, near or exceeding boiling).

As a general statement, it seems equally valid to conclude from the data presented in Table 1, that there may be a residual mid-loop operations concern at a few facilities, to be dealt with on a licensee specific basis, as it is to conclude (as the staff apparently has) that there is a broader generic problem that is continuing-or-escalating, and that must be dealt with by imposing a significant backfit.

5. The Committee may wish to discuss with the staff why BWRs are not included in the scope of this proposed action. Have there been no such events at BWR facilities? Are BWR decay heat removal systems inherently much more reliable, or are BWR operating staff training and performance much superior in this area? If the reason for excluding BWRs is that no such events have occurred in BWR facilities, why are B&W plants included? (There are no B&W plants included in the Table 1 data.)

6. The Committee may wish to discuss with the staff the minimum changes to the wording of the package submitted for CRGR review in this matter that would qualify the proposed "information request" as an information request _on_iy (rather than a de facto backfit, as indicated above). It appears that the minimum changes would be along the lines of the following in the areas indicated: ,

a. The wording of Background Item 1.a should be changed in Section 1 to l make clear that a new staff position is not being imposed, as  !

indicated in the Issue 1 discussion above.

b. The wording of Background Item 1 should be changed in Section 2. to make clear what the staff intends by the ters "minimal" cost for licensees in developing an acceptable response to this request, e.g. ,

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Can a licensee's response provide only a description of information already available at the sites (e.g. , existing analyses, procedures, etc.), or does the staff expect licensees )

to develop such analyses / procedures if none now exist? i Would a response simply to the ef fect that ". .we have no such information..." be considered an acceptable response to the proposed 50.54 request letter? Would any action be taken to shutdown the facilities of licensees responding thus? i 1

c. The wording of the proposed Generic Information Request Letter should be revised to reflect the changes indicated in a) and b) above. For example, the wording after the first sentence in the last para-  !

graph of page one of that letter could be changed to read as i follows:

"The staff believes that prudently this condition should be more fully considered to determina if additional requirements are warranted in this area. Accordingly, we request that you provide any existing safety assessments of operation during... including any l existing procedural guidance...(or any other information relevant to  !

these concerns that you wish to develop and submit voluntarily).

Information most useful to the staff in deciding whether any addi-tional new requirements should be imposed is in the following areas: 1

...(continue at the top of page 2. with no change).  ;

1 If the staff's assessment of the situation is such that they do not l believe that such a revised information request is adequate for l safety, then the proper course of action would appear to be to proceed immediately to impose explicitly any aroperly justified backfit deemed necessary for protection of pualic health and J safety.

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